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Question 1
Incorrect
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A 45 year old male patient is brought into the emergency department with a suspected massive pulmonary embolism. It is decided to intubate him pending transfer to ITU. Your consultant requests you prepare the patient for rapid sequence intubation. You start pre-oxygenating the patient. What is the gold standard evaluation for ensuring sufficient pre-oxygenation?
Your Answer: Blood gas pO2 ≥ 18 kPa
Correct Answer: End tidal O2 > 85%
Explanation:The blood gas measurement of pO2 should be equal to or greater than 18 kilopascals (kPa) at a level of 10.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 2
Incorrect
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You have been requested to arrange a teaching session on regional anesthesia for the recently inducted foundation doctors. Your task is to educate them about the application of Bier's block. What is the shortest duration for tourniquet placement during a Bier's block procedure?
Your Answer: 2 hours
Correct Answer: 20 minutes
Explanation:The minimum cuff inflation time for Bier’s block is set at 20 minutes, while the maximum time is 45 minutes. Similarly, the minimum tourniquet time is also 20 minutes, with a maximum of 45 minutes. The purpose of the minimum tourniquet time is to allow enough time for the local anaesthetic to bind to the local tissue and prevent it from being absorbed into the bloodstream. This helps reduce the risk of systemic toxicity from the anaesthetic. After 20 minutes, the chances of experiencing this toxicity should be significantly reduced. On the other hand, the maximum tourniquet time is set at 45 minutes to minimize the risk of complications such as distal ischaemia, nerve compression, and compartment syndrome.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 3
Correct
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A 30-year-old woman is brought in by ambulance following a car accident where her car was struck by a truck. She has suffered severe facial injuries and shows signs of airway obstruction. Her C-spine is triple immobilized. You perform a LEMON assessment for difficult intubation.
Which of the following factors indicates a difficult intubation?Your Answer: Mallampati score of 4
Explanation:Trauma patients who require a definitively secured airway include those who are apnoeic, have a Glasgow Coma Scale score of less than 9, experience sustained seizure activity, have unstable midface trauma or airway injuries, have a large flail segment or respiratory failure, have a high risk of aspiration, or are unable to maintain an airway or oxygenation through other means.
To predict difficult intubations, the LEMON assessment can be utilized. The LEMON mnemonic provides a systematic approach to assess potential challenges in intubation. It stands for the following:
– Look externally: Examine for any characteristics that are known to cause difficult intubation or ventilation.
– Evaluate the 3-3-2 rule: Measure the incisor distance, hyoid/mental distance, and thyroid-to-mouth distance. If any of these measurements are less than the specified number of fingerbreadths, it may indicate a difficult intubation.
– Mallampati: Assess the Mallampati score, which is a classification system based on the visibility of certain structures in the mouth and throat. A score of 3 or higher suggests a difficult intubation.
– Obstruction: Check for the presence of any conditions that could potentially obstruct the airway.
– Neck mobility: Evaluate the mobility of the patient’s neck, as limited mobility may make intubation more challenging.By utilizing the LEMON assessment, healthcare providers can identify potential difficulties in securing the airway and make appropriate interventions to ensure patient safety.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 4
Incorrect
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A 28 year old female presents at the emergency department with a circular saw laceration. You opt to examine the wound using local anesthesia. What is the maximum dosage of Prilocaine that can be administered?
Your Answer: 3 mg/Kg
Correct Answer: 6 mg/Kg
Explanation:The highest amount of Prilocaine that can be administered without adrenaline is 6 mg per kilogram of body weight. However, if Prilocaine is used in combination with adrenaline, the maximum dose increases to 8mg per kilogram.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 5
Correct
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A 42 year old male patient is brought into the emergency department due to a recent onset of high fever and feeling unwell that has worsened over the past day, with the patient becoming increasingly drowsy. Despite initial resuscitation efforts, there is minimal response and it is decided to intubate the patient before transferring to the intensive care unit for ventilatory and inotropic support. Your consultant requests that you apply pressure over the cricoid during the procedure. What is the reason for this?
Your Answer: Prevent aspiration of gastric contents
Explanation:Cricoid pressure is applied during intubation to compress the oesophagus and prevent the backflow of stomach contents, reducing the risk of aspiration.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 6
Correct
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A 28-year-old with a past of opioid misuse is brought into the ER after being discovered in a collapsed state with decreased level of consciousness. You are worried about the patient's airway. Your consultant recommends using a nasopharyngeal airway adjunct instead of an oropharyngeal airway adjunct. Why is a nasopharyngeal airway preferred in this scenario?
Your Answer: Less likely to provoke the gag reflex
Explanation:When a patient is semi-conscious, it is less likely for the nasopharyngeal airway adjuncts (NPA’s) to trigger the gag reflex compared to oropharyngeal airways. Therefore, NPA’s are typically the preferred option in these cases.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 7
Incorrect
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A 42 year old female is brought to the emergency department with a 15cm long laceration to her arm which occurred when she tripped and fell onto a sharp object. You are suturing the laceration under local anesthesia when the patient mentions experiencing numbness in her lips and feeling lightheaded. What is the probable diagnosis?
Your Answer: Torsades de pointes
Correct Answer: Local anaesthetic toxicity
Explanation:Early signs of local anaesthetic systemic toxicity (LAST) can include numbness around the mouth and tongue, a metallic taste in the mouth, feeling lightheaded or dizzy, and experiencing visual and auditory disturbances. LAST is a rare but serious complication that can occur when administering anesthesia. It is important for healthcare providers to be aware of the signs and symptoms of LAST, as early recognition can lead to better outcomes. Additionally, hyperventilation can temporarily lower calcium levels, which can cause numbness around the mouth.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 8
Incorrect
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You have just performed rapid sequence induction using ketamine and rocuronium and placed an endotracheal tube under consultant supervision. What is the time interval from administration of rocuronium to the onset of paralysis?
Your Answer: 5-10 minutes
Correct Answer: 45-60 seconds
Explanation:Both suxamethonium and rocuronium take approximately 45-60 seconds to induce paralysis. The time it takes for rocuronium to cause paralysis is similar to that of suxamethonium, which is also around 45-60 seconds.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 9
Correct
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A 45 year old female patient has been brought to the emergency department with multiple injuries following a fall while hiking in the mountains. You observe significant injuries to the face. There is also bruising to the chest wall and a fracture dislocation to the ankle. The patient has undergone rapid sequence induction with Propofol and Suxamethonium. A chest X-ray shows multiple rib fractures but no pneumothorax or visible pulmonary contusion. You notice that the patient's end tidal CO2 has steadily increased since being intubated from 4.5 KPa to 7.4 KPa. You observe esophageal temperature is 39.3ºC. What is the likely cause of these readings?
Your Answer: Malignant hyperthermia
Explanation:The earliest and most frequent clinical indication of malignant hyperthermia is typically an increase in end tidal CO2. An unexplained elevation in end tidal CO2 is often the initial and most reliable sign of this condition.
Further Reading:
Malignant hyperthermia is a rare and life-threatening syndrome that can be triggered by certain medications in individuals who are genetically susceptible. The most common triggers are suxamethonium and inhalational anaesthetic agents. The syndrome is caused by the release of stored calcium ions from skeletal muscle cells, leading to uncontrolled muscle contraction and excessive heat production. This results in symptoms such as high fever, sweating, flushed skin, rapid heartbeat, and muscle rigidity. It can also lead to complications such as acute kidney injury, rhabdomyolysis, and metabolic acidosis. Treatment involves discontinuing the trigger medication, administering dantrolene to inhibit calcium release and promote muscle relaxation, and managing any associated complications such as hyperkalemia and acidosis. Referral to a malignant hyperthermia center for further investigation is also recommended.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 10
Incorrect
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You are summoned to aid a 67-year-old patient who is in resus and has experienced two defibrillation attempts for cardiac arrest. Unfortunately, there is no supply of amiodarone available, so your consultant requests you to prepare lidocaine for administration following the next shock. What is the mechanism of action of lidocaine in the context of cardiac arrest?
Your Answer: Blockade of potassium channels
Correct Answer: Blockade of sodium channels
Explanation:Lidocaine functions by inhibiting the activity of voltage-gated sodium channels, preventing the flow of sodium ions through these channels.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 11
Incorrect
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A 68 year old has been brought to the emergency department by ambulance with a history of collapsing shortly after complaining of severe chest pain and difficulty breathing. It has been determined that the patient needs rapid sequence induction after pre-oxygenation. What is the best position for the patient to be in during pre-oxygenation?
Your Answer:
Correct Answer: 20-30 degrees head up tilt
Explanation:Several studies have shown that elevating the head by 20-30 degrees is beneficial for increasing oxygen levels compared to lying flat on the back.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 12
Incorrect
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You are managing a pediatric patient in the emergency department who needs sedation for suturing. You are considering using ketamine. What is an absolute contraindication to using ketamine in this case?
Your Answer:
Correct Answer: Aged less than 12 months
Explanation:Ketamine should not be used in children under 12 months old due to the increased risk of laryngospasm and airway complications. The Royal College of Emergency Medicine advises against using ketamine in children under 1 year old in the emergency department, and it should only be administered by experienced clinicians in children aged 5 and under. Ketamine may cause a slight increase in blood pressure and heart rate, making it a suitable option for those with low blood pressure. However, it is contraindicated in individuals with malignant hypertension (blood pressure above 180 mmHg). Please refer to the notes below for additional contraindications.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 13
Incorrect
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You are summoned to the resuscitation bay to provide assistance with a patient who has experienced cardiac arrest. The team is getting ready to administer amiodarone. What is the mechanism of action of amiodarone in the context of cardiac arrest?
Your Answer:
Correct Answer: Blockade of potassium channels
Explanation:Amiodarone functions by inhibiting voltage-gated potassium channels, leading to an extended repolarization period and decreased excitability of the heart muscle.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 14
Incorrect
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A 42 year old woman comes to the emergency department with a dislocated finger. You intend to perform a reduction under local anesthesia. The patient mentions that she used Entonox® during childbirth a decade ago and found it to be extremely effective. She inquires if she can use Entonox® for this procedure. What exactly is Entonox®?
Your Answer:
Correct Answer: 50% nitrous oxide and 50% oxygen
Explanation:Entonox®, also known as ‘gas and air’ or ‘laughing gas’, is a combination of nitrous oxide and oxygen in equal proportions. It offers a mild sedative effect and helps reduce anxiety.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 15
Incorrect
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You have a debrief session with your mentor after a case involving a patient who experienced systemic toxicity from local anesthesia. Towards the end of the conversation, your mentor emphasizes the importance of reporting such episodes. In the UK, which of the following organizations should be notified about incidents of local anesthetic systemic toxicity?
Your Answer:
Correct Answer: National Patient Safety Agency
Explanation:Instances of local anaesthetic systemic toxicity (LAST) should be promptly reported to the National Patient Safety Agency (NPSA). Additionally, it is advisable to report any adverse drug reactions to the Medicines and Healthcare products Regulatory Agency (MHRA) through their yellow card scheme. Please refer to the follow-up section in the notes for further details.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 16
Incorrect
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You examine the X-ray of a 65 year old male who has tripped and landed on his extended right hand. The X-ray confirms a fracture of the distal radius with dorsal displacement. You intend to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). How many healthcare professionals should be present during the entire procedure?
Your Answer:
Correct Answer: 2
Explanation:Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 17
Incorrect
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You are a member of the team assisting with the intubation of a pediatric patient. The initial intubation attempt is unsuccessful. Your attending physician instructs you to apply pressure on the larynx during the second attempt. With the patient positioned in a semi-recumbent position, which direction should pressure be applied to aid in intubation?
Your Answer:
Correct Answer: Backwards, upwards and rightwards
Explanation:The BURP maneuver is a technique used to assist with intubation. It involves applying pressure in a specific direction on the larynx. The acronym BURP stands for backwards (B), upwards (U), rightwards (R), and pressure (P). To perform the maneuver correctly, the thyroid cartilage is moved backwards, 2 cm upwards, and 0.5cm – 2 cm to the right in relation to the anatomical position.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 18
Incorrect
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A 15 year old male is brought to the emergency department by his parents after he fell while climbing over a fence and sustained a deep cut to the arm where the metal spike pierced the skin. An X-ray reveals no bone damage. You opt to examine and cleanse the wound under sedation as the patient is extremely upset. You choose to sedate the patient with Ketamine. What is the main way in which Ketamine works?
Your Answer:
Correct Answer: NMDA receptor antagonist
Explanation:Ketamine primarily works by blocking NMDA receptors, although its complete mechanism of action is not yet fully comprehended. Ongoing research is exploring its impact on various other receptors.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 19
Incorrect
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You are summoned to assist with a 72-year-old patient who is in the resuscitation bay and has experienced two defibrillation attempts following cardiac arrest. Unfortunately, there is no supply of amiodarone available, so your consultant instructs you to prepare lidocaine for administration after the next shock. What is the initial dosage of lidocaine to be given during cardiac arrest?
Your Answer:
Correct Answer: 1 mg/kg
Explanation:During cardiac arrest, Lidocaine is administered through a slow IV injection at an initial dose of 1 mg/kg when deemed suitable.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 20
Incorrect
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You are part of the team managing a conscious patient in the emergency room. You decide to insert a nasopharyngeal airway adjunct. How should you determine the appropriate size of the nasopharyngeal airway?
Your Answer:
Correct Answer: Sized according to the distance between the nostril and the tragus of the ear
Explanation:Nasopharyngeal airway adjuncts (NPAs) are selected based on their length, which should match the distance between the nostril and the tragus of the ear.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 21
Incorrect
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You assess a 16 year old with an open fracture dislocation of the ankle after a motorcycle accident. The patient has been given nitrous oxide during transportation in the ambulance. The orthopedic surgeon on call is currently in the emergency department and recommends that the injury be promptly treated in the operating room. Which of the following statements about nitrous oxide is correct?
Your Answer:
Correct Answer: Nitrous oxide administration increases the fractional content of inhaled anaesthetic gases
Explanation:The administration of nitrous oxide increases the amount of inhaled anaesthetic gases in the body through a phenomenon called the ‘second gas effect’. Nitrous oxide is much more soluble than nitrogen, with a solubility that is 20 to 30 times higher. When nitrous oxide is given, it causes a decrease in the volume of air in the alveoli. Additionally, nitrous oxide can enhance the absorption of other inhaled anaesthetic agents through the second gas effect. However, it is important to note that nitrous oxide alone cannot be used as the sole maintenance agent in anaesthesia.
Further Reading:
Entonox® is a mixture of 50% nitrous oxide and 50% oxygen that can be used for self-administration to reduce anxiety. It can also be used alongside other anesthesia agents. However, its mechanism of action for anxiety reduction is not fully understood. The Entonox bottles are typically identified by blue and white color-coded collars, but a new standard will replace these with dark blue shoulders in the future. It is important to note that Entonox alone cannot be used as the sole maintenance agent in anesthesia.
One of the effects of nitrous oxide is the second-gas effect, where it speeds up the absorption of other inhaled anesthesia agents. Nitrous oxide enters the alveoli and diffuses into the blood, displacing nitrogen. This displacement causes the remaining alveolar gases to become more concentrated, increasing the fractional content of inhaled anesthesia gases and accelerating the uptake of volatile agents into the blood.
However, when nitrous oxide administration is stopped, it can cause diffusion hypoxia. Nitrous oxide exits the blood and diffuses back into the alveoli, while nitrogen diffuses in the opposite direction. Nitrous oxide enters the alveoli much faster than nitrogen leaves, resulting in the dilution of oxygen within the alveoli. This can lead to diffusion hypoxia, where the oxygen concentration in the alveoli is diluted, potentially causing oxygen deprivation in patients breathing air.
There are certain contraindications for using nitrous oxide, as it can expand in air-filled spaces. It should be avoided in conditions such as head injuries with intracranial air, pneumothorax, recent intraocular gas injection, and entrapped air following a recent underwater dive.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 22
Incorrect
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A 45 year old male patient is brought into the emergency department with a suspected severe pulmonary embolism. It is decided to intubate him pending transfer to the intensive care unit. Your consultant requests you prepare the patient for rapid sequence intubation. You start pre-oxygenating the patient. What is the recommended minimum duration for sufficient pre-oxygenation?
Your Answer:
Correct Answer: 3 minutes
Explanation:Inspired oxygen primarily works by removing nitrogen from the lungs, which would otherwise take up a significant portion of the lung capacity. This nitrogen is replaced with oxygen, leading to improved oxygenation of the tissues and an increased oxygen reserve. As a result, the patient can safely hold their breath for a longer period of time. It is recommended to preoxygenate the patient for at least 3 minutes.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 23
Incorrect
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A 35 year old male is brought to the emergency department with severe head and chest injuries. As his GCS continues to decline, it is determined that intubation is necessary. You begin preparing for rapid sequence induction (RSI). What is the appropriate dosage of sodium thiopentone for an adult undergoing RSI?
Your Answer:
Correct Answer: 3-5 mg/kg
Explanation:To perform rapid sequence induction in adults, it is recommended to administer a dose of sodium thiopentone ranging from 3 to 5 mg per kilogram of body weight.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 24
Incorrect
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A 35-year-old woman is brought in by ambulance following a car accident where her car was hit by a truck. She has sustained severe facial injuries and shows signs of airway obstruction. Her cervical spine is immobilized. She has suffered significant midface trauma, and the anesthesiologist decides to secure a definitive airway by intubating the patient.
Which of the following does NOT indicate proper placement of the endotracheal tube?Your Answer:
Correct Answer: Presence of borborygmi in the epigastrium
Explanation:The presence of borborygmi in the epigastrium can indicate that the endotracheal tube (ETT) is incorrectly placed in the esophagus. There are several ways to verify the correct placement of the endotracheal tube (ETT).
One method is through direct visualization, where the ETT is observed passing through the vocal cords. Another method is by checking for fogging in the ETT, which can indicate proper placement. Auscultation of bilateral equal breath sounds is also a reliable way to confirm correct ETT placement.
Additionally, the absence of borborygmi in the epigastrium is a positive sign that the ETT is in the correct position. Capnography or using a CO2 detector can provide further confirmation of proper ETT placement. Finally, chest radiography can be used to visually assess the placement of the endotracheal tube.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 25
Incorrect
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You have just performed rapid sequence induction using ketamine and rocuronium and placed an endotracheal tube under the guidance of a consultant. What category of medication does rocuronium belong to?
Your Answer:
Correct Answer: Non-depolarizing neuromuscular blocker
Explanation:Rocuronium is a type of neuromuscular blocker that does not cause depolarization.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 26
Incorrect
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You are part of the team working on a child with severe burns. The child has a suspected inhalation injury and needs to be intubated before being transferred to the local burns unit. During direct laryngoscopy, which classification system is used to evaluate the glottic opening?
Your Answer:
Correct Answer: Cormack and Lehane classification
Explanation:The tracheal opening can be classified using the Cormack-Lehane grading system. This system categorizes the views obtained through direct laryngoscopy based on the structures that are visible. More information about this classification system can be found in the notes provided below.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 27
Incorrect
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A 32-year-old man with a history of severe asthma is brought to the Emergency Department by his girlfriend. He is experiencing extreme shortness of breath and wheezing, and his condition worsens rapidly. After receiving back-to-back nebulizer treatments, hydrocortisone, and IV magnesium sulfate, he is taken to resus, and the intensive care team is called for consultation. He is now severely hypoxic and has developed confusion. It is decided that the patient needs to be intubated.
Which of the following medications would be the most appropriate choice for inducing anesthesia in this patient?Your Answer:
Correct Answer: Ketamine
Explanation:Intubation is rarely necessary for asthmatic patients, with only about 2% of asthma attacks requiring it. Most severe cases can be managed using non-invasive ventilation techniques. However, intubation can be a life-saving measure for asthmatic patients in critical condition. The indications for intubation include severe hypoxia, altered mental state, failure to respond to medications or non-invasive ventilation, and respiratory or cardiac arrest.
Before intubation, it is important to preoxygenate the patient and administer intravenous fluids. Nasal oxygen during intubation can provide additional time. Intravenous fluids are crucial because patients with acute asthma exacerbations can experience significant fluid loss, which can lead to severe hypotension during intubation and positive pressure ventilation.
There is no perfect combination of drugs for rapid sequence induction (RSI), but ketamine is often the preferred choice. Ketamine has bronchodilatory properties and does not cause hypotension as a side effect. Propofol can also be used, but it carries a risk of hypotension. In some cases, a subdissociative dose of ketamine can be helpful to facilitate the use of non-invasive ventilation in a hypoxic or combative patient.
Rocuronium and suxamethonium are commonly used as paralytic agents. Rocuronium has the advantage of providing a longer period of paralysis, which helps avoid ventilator asynchrony in the early stages of management.
Proper mechanical ventilation is essential, and it involves allowing the patient enough time to fully exhale the delivered breath and prevent hyperinflation. Therefore, permissive hypercapnia is typically used, and the ventilator settings should be adjusted accordingly. The recommended settings are a respiratory rate of 6-8 breaths per minute and a tidal volume of 6 ml per kilogram of body weight.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 28
Incorrect
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A 32-year-old man that has been involved in a car crash develops symptoms of acute airway blockage. You conclude that he needs to be intubated using a rapid sequence induction. You intend to use thiopental sodium as your induction medication.
What type of receptor does thiopental sodium act on to produce its effects?Your Answer:
Correct Answer: Gamma-aminobutyric acid (GABA)
Explanation:Thiopental sodium is a barbiturate with a very short duration of action. It is primarily used to induce anesthesia. Barbiturates are believed to primarily affect synapses by reducing the sensitivity of postsynaptic receptors to neurotransmitters and by interfering with the release of neurotransmitters from presynaptic neurons.
Thiopental sodium specifically binds to a unique site associated with a chloride ionophore at the GABAA receptor, which is responsible for the opening of chloride ion channels. This binding increases the length of time that the chloride ionophore remains open. As a result, the inhibitory effect of GABA on postsynaptic neurons in the thalamus is prolonged.
In summary, thiopental sodium acts as a short-acting barbiturate that is commonly used to induce anesthesia. It affects synapses by reducing postsynaptic receptor sensitivity and interfering with neurotransmitter release. By binding to a specific site at the GABAA receptor, thiopental sodium prolongs the inhibitory effect of GABA in the thalamus.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 29
Incorrect
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A 32-year-old patient presents to the emergency department with a 6 cm leg laceration. After assessing the wound, it is determined that suturing under anesthesia is necessary. You intend to supervise one of the medical students in closing the wound. Before beginning the procedure, you have a discussion about the risks associated with local anesthesia. Methemoglobinemia is primarily associated with which type of anesthetic agent?
Your Answer:
Correct Answer: Prilocaine
Explanation:Methaemoglobinaemia is a condition that can occur when prilocaine is used, particularly when administered at doses higher than 16 mg/kg.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 30
Incorrect
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A 32-year-old man that has been involved in a car crash develops symptoms of acute airway blockage. You determine that he needs intubation through a rapid sequence induction. You intend to use etomidate as your induction medication.
Etomidate functions by acting on what type of receptor?Your Answer:
Correct Answer: Gamma-aminobutyric acid (GABA)
Explanation:Etomidate is a derivative of imidazole that is commonly used to induce anesthesia due to its short-acting nature. Its main mechanism of action is believed to involve the modulation of fast inhibitory synaptic transmission within the central nervous system by acting on GABA type A receptors.
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This question is part of the following fields:
- Basic Anaesthetics
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