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.

Traumatic aortic rupture, also known as traumatic aortic disruption or transection, occurs when the aorta is torn or ruptured due to physical trauma. This condition often leads to sudden death because of severe bleeding. Motor vehicle accidents and falls from great heights are the most common causes of this injury.

The patients with the highest chances of survival are those who have an incomplete tear near the ligamentum arteriosum of the proximal descending aorta, close to where the left subclavian artery branches off. The presence of an intact adventitial layer or contained mediastinal hematoma helps maintain continuity and prevents immediate bleeding and death. If promptly identified and treated, survivors of these injuries can recover. In cases where traumatic aortic rupture leads to sudden death, approximately 50% of patients have damage at the aortic isthmus, while around 15% have damage in either the ascending aorta or the aortic arch.

Initial chest X-rays may show signs consistent with a traumatic aortic injury. However, false-positive and false-negative results can occur, and sometimes there may be no abnormalities visible on the X-ray. Some of the possible X-ray findings include a widened mediastinum, hazy left lung field, obliteration of the aortic knob, fractures of the 1st and 2nd ribs, deviation of the trachea to the right, presence of a pleural cap, elevation and rightward shift of the right mainstem bronchus, depression of the left mainstem bronchus, obliteration of the space between the pulmonary artery and aorta, and deviation of the esophagus or NG tube to the right.

A helical contrast-enhanced CT scan of the chest is the preferred initial investigation for suspected blunt aortic injury. It has proven to be highly accurate, with close to 100% sensitivity and specificity. CT scanning should be performed liberally, as chest X-ray findings can be unreliable. However, hemodynamically unstable patients should not be placed in a CT scanner. If the CT results are inconclusive, aortography or trans-oesophageal echo can be performed for further evaluation.

Immediate surgical intervention is necessary for these injuries. Endovascular repair is the most common method used and has excellent short-term outcomes. Open repair may also be performed depending on the circumstances. It is important to control heart rate and blood pressure during stabilization to reduce the risk of rupture. Pain should be managed with appropriate analgesic

When there is damage to the facial nerve in the LMN, the patient will experience paralysis in the forehead and will be unable to wrinkle their brow. However, in an upper motor neuron lesion, the frontalis muscle is not affected, so the patient can still furrow their brow normally and their ability to close their eyes and blink is not affected. Lower motor neuron lesions affect the final part of the nerve pathway to all branches of the facial nerve, resulting in paralysis of the forehead and the rest of the face on that side. It is important to note that the speed of onset may provide some clues about the cause of the lesion, but it does not help determine the specific location of the damage.

Further Reading:

Bell’s palsy is a condition characterized by sudden weakness or paralysis of the facial nerve, resulting in facial muscle weakness or drooping. The exact cause is unknown, but it is believed to be related to viral infections such as herpes simplex or varicella zoster. It is more common in individuals aged 15-45 years and those with diabetes, obesity, hypertension, or upper respiratory conditions. Pregnancy is also a risk factor.

Diagnosis of Bell’s palsy is typically based on clinical symptoms and ruling out other possible causes of facial weakness. Symptoms include rapid onset of unilateral facial muscle weakness, drooping of the eyebrow and corner of the mouth, loss of the nasolabial fold, otalgia, difficulty chewing or dry mouth, taste disturbance, eye symptoms such as inability to close the eye completely, dry eye, eye pain, and excessive tearing, numbness or tingling of the cheek and mouth, speech articulation problems, and hyperacusis.

When assessing a patient with facial weakness, it is important to consider other possible differentials such as stroke, facial nerve tumors, Lyme disease, granulomatous diseases, Ramsay Hunt syndrome, mastoiditis, and chronic otitis media. Red flags for these conditions include insidious and painful onset, duration of symptoms longer than 3 months with frequent relapses, pre-existing risk factors, systemic illness or fever, vestibular or hearing abnormalities, and other cranial nerve involvement.

Management of Bell’s palsy involves the use of steroids, eye care advice, and reassurance. Steroids, such as prednisolone, are recommended for individuals presenting within 72 hours of symptom onset. Eye care includes the use of lubricating eye drops, eye ointment at night, eye taping if unable to close the eye at night, wearing sunglasses, and avoiding dusty environments. Reassurance is important as the majority of patients make a complete recovery within 3-4 months. However, some individuals may experience sequelae such as facial asymmetry, gustatory lacrimation, inadequate lid closure, brow ptosis, drooling, and hemifacial spasms.

Antiviral treatments are not currently recommended as a standalone treatment for Bell’s palsy, but they may be given in combination with corticosteroids on specialist advice. Referral to an ophthalmologist is necessary if the patient has eye symptoms such as pain, irritation, or itch.

The lingual nerve, a branch of the mandibular division of the trigeminal nerve, provides sensory innervation to the front two-thirds of the tongue and the floor of the mouth. It also carries fibers of the chorda tympani, a branch of the facial nerve, which returns taste information from the front two-thirds of the tongue. The diagram below illustrates the relationships of the lingual nerve in the oral cavity.

The most common cause of lingual nerve injuries is wisdom tooth surgery. Approximately 2% of wisdom tooth extractions result in temporary injury, while permanent damage occurs in 0.2% of cases. Additionally, the nerve can be harmed during dental injections for local anesthesia.

The anterior superior alveolar nerve, a branch of the maxillary division of the trigeminal nerve, provides sensation to the incisor and canine teeth.

The inferior alveolar nerve, another branch of the mandibular division of the trigeminal nerve, supplies sensation to the lower teeth.

The zygomatic nerve, a branch of the maxillary division of the trigeminal nerve, offers sensation to the skin over the zygomatic and temporal bones.

Lastly, the mylohyoid nerve is a motor nerve that supplies the mylohyoid and the anterior belly of the digastric.

This patient is exhibiting the psoas sign, which is a medical indication of irritation in the iliopsoas group of hip flexors located in the abdomen. In this particular case, it is highly likely that the patient has acute appendicitis.

The psoas sign can be observed by extending the patient’s thigh while they are lying on their side with their knees extended, or by asking the patient to actively flex their thigh at the hip. If these movements result in abdominal pain or if the patient resists due to pain, then the psoas sign is considered positive.

The pain occurs because the psoas muscle is adjacent to the peritoneal cavity. When the muscles are stretched or contracted, they rub against the inflamed tissues nearby, causing discomfort. This strongly suggests that the appendix is positioned retrocaecal.

The recommended dose of adrenaline is 7 mg per kilogram of body weight, with a maximum limit of 500 mg.

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.

Central retinal vein occlusion (CRVO) is a condition that usually leads to painless, one-sided vision loss. When examining the retina, it may appear similar to a ‘pizza thrown against a wall’, with swollen retinal veins, swelling of the optic disc, numerous flame-shaped hemorrhages, and cotton wool spots. Hypertension is present in about 65% of CRVO cases and is more common in individuals aged 65 and above.

On the other hand, branch retinal vein occlusion (BRVO) typically affects only one section of the retina, resulting in visual field deficits in that specific quadrant rather than complete vision loss.

Korsakoff syndrome is a form of dementia that occurs due to a lack of thiamine (vitamin B1) in the body. This condition is most commonly observed in individuals who have a long history of alcoholism. The main features of Korsakoff syndrome include anterograde amnesia, patchy retrograde amnesia, and confabulation. Additionally, many patients also experience difficulties with language (aphasia), movement (apraxia), recognition (agnosia), or executive functioning. It is important to note that Korsakoff syndrome often coexists with Wernicke’s encephalopathy, which is characterized by a triad of symptoms including ophthalmoplegia, altered mental state, and gait disturbance (ataxia). When both conditions are present, it is referred to as Wernicke-Korsakoff syndrome (WKS).

The intravascular volume of an infant is approximately 80 ml/kg. In older children, the intravascular volume is around 70 ml/kg.

Dehydration itself does not lead to death, but shock can. Shock can occur when there is a loss of 20 ml/kg from the intravascular space, while clinical dehydration is only noticeable after total losses of more than 25 ml/kg.

The maintenance fluid requirements for healthy, typical children are summarized in the table below:

Bodyweight:
– First 10 kg: Daily fluid requirement of 100 ml/kg, hourly fluid requirement of 4 ml/kg
– Second 10 kg: Daily fluid requirement of 50 ml/kg, hourly fluid requirement of 2 ml/kg
– Subsequent kg: Daily fluid requirement of 20 ml/kg, hourly fluid requirement of 1 ml/kg

Therefore, this child’s daily maintenance fluid requirement can be calculated as follows:

– First 10 kg: 100 ml/kg = 1000 ml
– Second 10 kg: 50 ml/kg = 500 ml
– Subsequent kg: 20 ml/kg = 40 ml

Total daily maintenance fluid requirement: 1540 ml

Atropine acts as a blocker for muscarinic acetylcholine receptors, making it an antagonist. It is commonly administered during peri-arrest bradycardia. In adults, a dose of 500 mcg is given every 3-5 minutes, with a maximum total dose of 3mg. On the other hand, the initial intravenous dose of amiodarone is 300 mg. Amiodarone works by prolonging repolarization and decreasing myocardial excitability. Additionally, lidocaine functions by blocking sodium 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.