The risk of infection is highest with femoral central lines.

A central venous catheter (CVC) is a type of catheter that is inserted into a large vein in the body, typically in the neck, chest, or groin. It has several important uses, including CVP monitoring, pulmonary artery pressure monitoring, repeated blood sampling, IV access for large volumes of fluids or drugs, TPN administration, dialysis, pacing, and other procedures such as placement of IVC filters or venous stents.

When inserting a central line, it is ideal to use ultrasound guidance to ensure accurate placement. However, there are certain contraindications to central line insertion, including infection or injury to the planned access site, coagulopathy, thrombosis or stenosis of the intended vein, a combative patient, or raised intracranial pressure for jugular venous lines.

The most common approaches for central line insertion are the internal jugular, subclavian, femoral, and PICC (peripherally inserted central catheter) veins. The internal jugular vein is often chosen due to its proximity to the carotid artery, but variations in anatomy can occur. Ultrasound can be used to identify the vessels and guide catheter placement, with the IJV typically lying superficial and lateral to the carotid artery. Compression and Valsalva maneuvers can help distinguish between arterial and venous structures, and doppler color flow can highlight the direction of flow.

In terms of choosing a side for central line insertion, the right side is usually preferred to avoid the risk of injury to the thoracic duct and potential chylothorax. However, the left side can also be used depending on the clinical situation.

Femoral central lines are another option for central venous access, with the catheter being inserted into the femoral vein in the groin. Local anesthesia is typically used to establish a field block, with lidocaine being the most commonly used agent. Lidocaine works by blocking sodium channels and preventing the propagation of action potentials.

In summary, central venous catheters have various important uses and should ideally be inserted using ultrasound guidance. There are contraindications to their insertion, and different approaches can be used depending on the clinical situation. Local anesthesia is commonly used for central line insertion, with lidocaine being the preferred agent.

The primary cause for the majority of out-of-hospital cardiac arrests is cardiovascular disease. This refers to conditions that affect the heart and blood vessels, such as coronary artery disease, heart attacks, and arrhythmias. These conditions can lead to sudden cardiac arrest.

Further Reading:

Cardiopulmonary arrest is a serious event with low survival rates. In non-traumatic cardiac arrest, only about 20% of patients who arrest as an in-patient survive to hospital discharge, while the survival rate for out-of-hospital cardiac arrest is approximately 8%. The Resus Council BLS/AED Algorithm for 2015 recommends chest compressions at a rate of 100-120 per minute with a compression depth of 5-6 cm. The ratio of chest compressions to rescue breaths is 30:2.

After a cardiac arrest, the goal of patient care is to minimize the impact of post cardiac arrest syndrome, which includes brain injury, myocardial dysfunction, the ischaemic/reperfusion response, and the underlying pathology that caused the arrest. The ABCDE approach is used for clinical assessment and general management. Intubation may be necessary if the airway cannot be maintained by simple measures or if it is immediately threatened. Controlled ventilation is aimed at maintaining oxygen saturation levels between 94-98% and normocarbia. Fluid status may be difficult to judge, but a target mean arterial pressure (MAP) between 65 and 100 mmHg is recommended. Inotropes may be administered to maintain blood pressure. Sedation should be adequate to gain control of ventilation, and short-acting sedating agents like propofol are preferred. Blood glucose levels should be maintained below 8 mmol/l. Pyrexia should be avoided, and there is some evidence for controlled mild hypothermia but no consensus on this.

Post ROSC investigations may include a chest X-ray, ECG monitoring, serial potassium and lactate measurements, and other imaging modalities like ultrasonography, echocardiography, CTPA, and CT head, depending on availability and skills in the local department. Treatment should be directed towards the underlying cause, and PCI or thrombolysis may be considered for acute coronary syndrome or suspected pulmonary embolism, respectively.

Patients who are comatose after ROSC without significant pre-arrest comorbidities should be transferred to the ICU for supportive care. Neurological outcome at 72 hours is the best prognostic indicator of outcome.

The subclavian approach for central lines carries the highest risk of pneumothorax. However, it does have advantages such as being accessible during airway control and having easily identifiable landmarks for insertion, even in obese patients. It is important to note that the carotid is not used for CVC’s.

Further Reading:

A central venous catheter (CVC) is a type of catheter that is inserted into a large vein in the body, typically in the neck, chest, or groin. It has several important uses, including CVP monitoring, pulmonary artery pressure monitoring, repeated blood sampling, IV access for large volumes of fluids or drugs, TPN administration, dialysis, pacing, and other procedures such as placement of IVC filters or venous stents.

When inserting a central line, it is ideal to use ultrasound guidance to ensure accurate placement. However, there are certain contraindications to central line insertion, including infection or injury to the planned access site, coagulopathy, thrombosis or stenosis of the intended vein, a combative patient, or raised intracranial pressure for jugular venous lines.

The most common approaches for central line insertion are the internal jugular, subclavian, femoral, and PICC (peripherally inserted central catheter) veins. The internal jugular vein is often chosen due to its proximity to the carotid artery, but variations in anatomy can occur. Ultrasound can be used to identify the vessels and guide catheter placement, with the IJV typically lying superficial and lateral to the carotid artery. Compression and Valsalva maneuvers can help distinguish between arterial and venous structures, and doppler color flow can highlight the direction of flow.

In terms of choosing a side for central line insertion, the right side is usually preferred to avoid the risk of injury to the thoracic duct and potential chylothorax. However, the left side can also be used depending on the clinical situation.

Femoral central lines are another option for central venous access, with the catheter being inserted into the femoral vein in the groin. Local anesthesia is typically used to establish a field block, with lidocaine being the most commonly used agent. Lidocaine works by blocking sodium channels and preventing the propagation of action potentials.

In summary, central venous catheters have various important uses and should ideally be inserted using ultrasound guidance. There are contraindications to their insertion, and different approaches can be used depending on the clinical situation. Local anesthesia is commonly used for central line insertion, with lidocaine being the preferred agent.

The size of the cannula used for IV fluid infusion determines the maximum flow rate. For a 20g cannula, the maximum flow rate is around 60 ml per minute. As a result, the fastest infusion time through a 20g cannula is approximately 15 minutes for a maximum volume of 1000 ml.

Further Reading:

Peripheral venous cannulation is a procedure that should be performed following established guidelines to minimize the risk of infection, injury, extravasation, and early failure of the cannula. It is important to maintain good hand hygiene, use personal protective equipment, ensure sharps safety, and employ an aseptic non-touch technique during the procedure.

According to the National Institute for Health and Care Excellence (NICE), the skin should be disinfected with a solution of 2% chlorhexidine gluconate and 70% alcohol before inserting the catheter. It is crucial to allow the disinfectant to completely dry before inserting the cannula.

The flow rates of IV cannulas can vary depending on factors such as the gauge, color, type of fluid used, presence of a bio-connector, length of the cannula, and whether the fluid is drained under gravity or pumped under pressure. However, the following are typical flow rates for different gauge sizes: 14 gauge (orange) has a flow rate of 270 ml/minute, 16 gauge (grey) has a flow rate of 180 ml/minute, 18 gauge (green) has a flow rate of 90 ml/minute, 20 gauge (pink) has a flow rate of 60 ml/minute, and 22 gauge (blue) has a flow rate of 36 ml/minute. These flow rates are based on infusing 1000 ml of normal saline under ideal circumstances, but they may vary in practice.

A tension pneumothorax occurs when there is an air leak from the lung or chest wall that acts like a one-way valve. This causes air to build up in the pleural space without any way to escape. As a result, pressure in the pleural space increases and pushes the mediastinum into the opposite hemithorax. If left untreated, this can lead to cardiovascular instability, shock, and cardiac arrest.

The clinical features of tension pneumothorax include respiratory distress and cardiovascular instability. Tracheal deviation away from the side of the injury, unilateral absence of breath sounds on the affected side, and a hyper-resonant percussion note are also characteristic. Other signs include distended neck veins and cyanosis, which is a late sign. It’s important to note that both tension pneumothorax and massive haemothorax can cause decreased breath sounds on auscultation. However, percussion can help differentiate between the two conditions. Hyper-resonance suggests tension pneumothorax, while dullness suggests a massive haemothorax.

Tension pneumothorax is a clinical diagnosis and should not be delayed for radiological confirmation. Requesting a chest X-ray in this situation can delay treatment and put the patient at risk. Immediate decompression through needle thoracocentesis is the recommended treatment. Traditionally, a large-bore needle or cannula is inserted into the 2nd intercostal space in the midclavicular line of the affected hemithorax. However, studies on cadavers have shown better success in reaching the thoracic cavity when the 4th or 5th intercostal space in the midaxillary line is used in adult patients. ATLS now recommends this location for needle decompression in adults. The site for needle thoracocentesis in children remains the same, using the 2nd intercostal space in the midclavicular line. It’s important to remember that needle thoracocentesis is a temporary measure, and the insertion of a chest drain is the definitive treatment.

After the third shock is administered to patients with a shockable rhythm, it is recommended to administer two drugs: adrenaline and amiodarone. Adrenaline should be given at a dose of 1 mg intravenously (or intraosseously) for adult patients in cardiac arrest with a shockable rhythm. For adult patients in cardiac arrest who are in ventricular fibrillation or pulseless ventricular tachycardia, amiodarone should be given at a dose of 300 mg intravenously (or intraosseously) after three shocks have been administered. In cases where amiodarone is unavailable, lidocaine may be used as an alternative.

Further Reading:

Cardiopulmonary arrest is a serious event with low survival rates. In non-traumatic cardiac arrest, only about 20% of patients who arrest as an in-patient survive to hospital discharge, while the survival rate for out-of-hospital cardiac arrest is approximately 8%. The Resus Council BLS/AED Algorithm for 2015 recommends chest compressions at a rate of 100-120 per minute with a compression depth of 5-6 cm. The ratio of chest compressions to rescue breaths is 30:2.

After a cardiac arrest, the goal of patient care is to minimize the impact of post cardiac arrest syndrome, which includes brain injury, myocardial dysfunction, the ischaemic/reperfusion response, and the underlying pathology that caused the arrest. The ABCDE approach is used for clinical assessment and general management. Intubation may be necessary if the airway cannot be maintained by simple measures or if it is immediately threatened. Controlled ventilation is aimed at maintaining oxygen saturation levels between 94-98% and normocarbia. Fluid status may be difficult to judge, but a target mean arterial pressure (MAP) between 65 and 100 mmHg is recommended. Inotropes may be administered to maintain blood pressure. Sedation should be adequate to gain control of ventilation, and short-acting sedating agents like propofol are preferred. Blood glucose levels should be maintained below 8 mmol/l. Pyrexia should be avoided, and there is some evidence for controlled mild hypothermia but no consensus on this.

Post ROSC investigations may include a chest X-ray, ECG monitoring, serial potassium and lactate measurements, and other imaging modalities like ultrasonography, echocardiography, CTPA, and CT head, depending on availability and skills in the local department. Treatment should be directed towards the underlying cause, and PCI or thrombolysis may be considered for acute coronary syndrome or suspected pulmonary embolism, respectively.

Patients who are comatose after ROSC without significant pre-arrest comorbidities should be transferred to the ICU for supportive care. Neurological outcome at 72 hours is the best prognostic indicator of outcome.

In patients with hypothermia, the pulse check during CPR should be extended to 1 minute. Additionally, several adjustments need to be made to the CPR protocol. Firstly, mechanical ventilation should be used due to the stiffness of the chest wall. Secondly, the dosing or omission of cardiac arrest drugs should be adjusted based on the patient’s temperature. The defibrillation pattern should also be modified, with 3 shocks attempted before re-attempting defibrillation only when the body temperature is above 30ºC. Certain electrolyte disturbances, such as mild hypokalemia, should not be treated as potassium levels typically rise with Rewarming. It is important to plan for prolonged resuscitation in these cases. Lastly, uncorrected ABG results should be used, without adjusting for temperature.

Further Reading:

Hypothermic cardiac arrest is a rare situation that requires a tailored approach. Resuscitation is typically prolonged, but the prognosis for young, previously healthy individuals can be good. Hypothermic cardiac arrest may be associated with drowning. Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, basal metabolic rate falls and cell signaling between neurons decreases, leading to reduced tissue perfusion. Signs and symptoms of hypothermia progress as the core temperature drops, initially presenting as compensatory increases in heart rate and shivering, but eventually ceasing as the temperature drops into moderate hypothermia territory.

ECG changes associated with hypothermia include bradyarrhythmias, Osborn waves, prolonged PR, QRS, and QT intervals, shivering artifact, ventricular ectopics, and cardiac arrest. When managing hypothermic cardiac arrest, ALS should be initiated as per the standard ALS algorithm, but with modifications. It is important to check for signs of life, re-warm the patient, consider mechanical ventilation due to chest wall stiffness, adjust dosing or withhold drugs due to slowed drug metabolism, and correct electrolyte disturbances. The resuscitation of hypothermic patients is often prolonged and may continue for a number of hours.

Pulse checks during CPR may be difficult due to low blood pressure, and the pulse check is prolonged to 1 minute for this reason. Drug metabolism is slowed in hypothermic patients, leading to a build-up of potentially toxic plasma concentrations of administered drugs. Current guidance advises withholding drugs if the core temperature is below 30ºC and doubling the drug interval at core temperatures between 30 and 35ºC. Electrolyte disturbances are common in hypothermic patients, and it is important to interpret results keeping the setting in mind. Hypoglycemia should be treated, hypokalemia will often correct as the patient re-warms, ABG analyzers may not reflect the reality of the hypothermic patient, and severe hyperkalemia is a poor prognostic indicator.

Different warming measures can be used to increase the core body temperature, including external passive measures such as removal of wet clothes and insulation with blankets, external active measures such as forced heated air or hot-water immersion, and internal active measures such as inhalation of warm air, warmed intravenous fluids, gastric, bladder, peritoneal and/or pleural lavage and high volume renal haemofilter.

The arterial line needle is inserted into the skin at an angle between 30 and 45 degrees. For a more detailed demonstration, please refer to the video provided in the media links section.

Further Reading:

Arterial line insertion is a procedure used to monitor arterial blood pressure continuously and obtain frequent blood gas samples. It is typically done when non-invasive blood pressure monitoring is not possible or when there is an anticipation of hemodynamic instability. The most common site for arterial line insertion is the radial artery, although other sites such as the ulnar, brachial, axillary, posterior tibial, femoral, and dorsalis pedis arteries can also be used.

The radial artery is preferred for arterial line insertion due to its superficial location, ease of identification and access, and lower complication rate compared to other sites. Before inserting the arterial line, it is important to perform Allen’s test to check for collateral circulation to the hand.

The procedure begins by identifying the artery by palpating the pulse at the wrist and confirming its position with doppler ultrasound if necessary. The wrist is then positioned dorsiflexed, and the skin is prepared and aseptic technique is maintained throughout the procedure. Local anesthesia is infiltrated at the insertion site, and the catheter needle is inserted at an angle of 30-45 degrees to the skin. Once flashback of pulsatile blood is seen, the catheter angle is flattened and advanced a few millimeters into the artery. Alternatively, a guide wire can be used with an over the wire technique.

After the catheter is advanced, the needle is withdrawn, and the catheter is connected to the transducer system and secured in place with sutures. It is important to be aware of absolute and relative contraindications to arterial line placement, as well as potential complications such as infection, thrombosis, hemorrhage, emboli, pseudo-aneurysm formation, AV fistula formation, arterial dissection, and nerve injury/compression.

Overall, arterial line insertion is a valuable procedure for continuous arterial blood pressure monitoring and frequent blood gas sampling, and the radial artery is the most commonly used site due to its accessibility and lower complication rate.

Defibrillation is a procedure used to treat two specific cardiac rhythms, ventricular fibrillation and pulseless ventricular tachycardia. It involves delivering an electrical shock randomly during the cardiac cycle to restore a normal heart rhythm. It is important to note that defibrillation is different from cardioversion, which involves delivering energy synchronized to the QRS complex.

Further Reading:

In the event of an adult experiencing cardiorespiratory arrest, it is crucial for doctors to be familiar with the Advanced Life Support (ALS) algorithm. They should also be knowledgeable about the proper technique for chest compressions, the appropriate rhythms for defibrillation, the reversible causes of arrest, and the drugs used in advanced life support.

During chest compressions, the rate should be between 100-120 compressions per minute, with a depth of compression of 5-6 cm. The ratio of chest compressions to rescue breaths should be 30:2. It is important to change the person giving compressions regularly to prevent fatigue.

There are two shockable ECG rhythms that doctors should be aware of: ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). These rhythms require defibrillation.

There are four reversible causes of cardiorespiratory arrest, known as the 4 H’s and 4 T’s. The 4 H’s include hypoxia, hypovolemia, hypo or hyperkalemia or metabolic abnormalities, and hypothermia. The 4 T’s include thrombosis (coronary or pulmonary), tension pneumothorax, tamponade, and toxins. Identifying and treating these reversible causes is crucial for successful resuscitation.

When it comes to resus drugs, they are considered of secondary importance during CPR due to the lack of high-quality evidence for their efficacy. However, adrenaline (epinephrine) and amiodarone are the two drugs included in the ALS algorithm. Doctors should be familiar with the dosing, route, and timing of administration for both drugs.

Adrenaline should be administered intravenously at a concentration of 1 in 10,000 (100 micrograms/mL). It should be repeated every 3-5 minutes. Amiodarone is initially given at a dose of 300 mg, either from a pre-filled syringe or diluted in 20 mL of Glucose 5%. If required, an additional dose of 150 mg can be given by intravenous injection. This is followed by an intravenous infusion of 900 mg over 24 hours. The first dose of amiodarone is given after 3 shocks.

Before performing arterial blood gas sampling, it is necessary to disinfect the skin. This is typically done using alcohol, which should be applied and given enough time to dry completely before proceeding with the skin puncture. In the UK, it is common to use solutions that combine alcohol with Chlorhexidine, such as Chloraprep® (2).

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.