A 72-year-old hospitalized man is evaluated for new-onset paresthesia in the right hand. The patient was admitted to the intensive care unit 4 days ago due to pneumonia complicated by respiratory failure and septic shock. He was mechanically ventilated and treated with broad-spectrum antibiotics, intravenous fluids, and vasopressor therapy. Hemodynamic monitoring was performed using a right internal jugular venous catheter and a right brachial arterial catheter. The patient's clinical condition gradually improved. Today, he was extubated, and the arterial and venous catheters were removed. Since extubation, the patient has reported right hand discomfort with tingling and numbness. On examination, both hands are warm with 2-second capillary refill. Bilateral grip strength is diminished but symmetric, and sensation to light touch and pain is diminished in the lateral palm, thumb, index finger, and long finger of the right hand. Which of the following is the most likely cause of this patient's hand symptoms?

Question

A 72-year-old hospitalized man is evaluated for new-onset paresthesia in the right hand.  The patient was admitted to the intensive care unit 4 days ago due to pneumonia complicated by respiratory failure and septic shock.  He was mechanically ventilated and treated with broad-spectrum antibiotics, intravenous fluids, and vasopressor therapy.  Hemodynamic monitoring was performed using a right internal jugular venous catheter and a right brachial arterial catheter.  The patient's clinical condition gradually improved.  Today, he was extubated, and the arterial and venous catheters were removed.  Since extubation, the patient has reported right hand discomfort with tingling and numbness.  On examination, both hands are warm with 2-second capillary refill.  Bilateral grip strength is diminished but symmetric, and sensation to light touch and pain is diminished in the lateral palm, thumb, index finger, and long finger of the right hand.  Which of the following is the most likely cause of this patient's hand symptoms?

Quizplus · Accepted Answer

11ec25c8_d574_7a51_bc81_770867e3ea9b_MD0003_00 This patient has new-onset paresthesia and diminished sensation in the distribution of the right median nerve. Given his recent history of right brachial artery cannulation and the adjacency of the brachial artery to the median nerve in the distal upper arm, the most likely cause of his hand symptoms is median nerve injury. median nerve In patients who are experiencing shock and/or receiving vasopressor therapy, central venous (eg, internal jugular) catheters are used for delivery of vasopressors (and other medications or intravenous fluids) whereas indwelling arterial catheters are used for continuous blood pressure monitoring and frequent arterial blood sampling. Most commonly, the radial artery is used due to its accessibility (ie, superficial location) and the typical presence of collateral circulation (ie, ulnar artery) to the hand. However, the brachial artery is sometimes used because of its increased reliability (ie, lower occlusion rates) and accuracy (ie, closer correlation with central aortic pressure) or if there are technical difficulties with radial artery cannulation. Brachial artery cannulation is typically performed just proximal to the elbow crease. At this level, the median nerve lies directly medial to the brachial artery and can be lacerated by the seeker needle used to insert the arterial catheter (rare) or compressed by a postprocedural hematoma or local swelling (common). This patient's symptoms are most likely due to compression because there are no motor deficits, which would typically be expected with laceration. Spontaneous symptom resolution is expected within days to weeks. (Choice A) Brachial artery cannulation can be complicated by thrombosis, but this usually results in acute limb ischemia distally due to minimal collateral circulation. This patient's hands are warm bilaterally with normal capillary refill. acute limb ischemia (Choice B) Brachial plexus injury (eg, compression from hematoma) can occur as a complication of internal jugular vein cannulation. However, this patient's sensory deficit is in a peripheral nerve (ie, median) distribution rather than a nerve root (ie, dermatomal), trunk, or cord distribution. (Choice C) Cerebral infarction can be caused by hypoperfusion during shock. However, it is unlikely to cause an isolated deficit in the distribution of a peripheral (eg, median) nerve. (Choice D) Critical illness neuropathy can occur after severe sepsis. However, it is typically a polyneuropathy that causes severe, diffuse, symmetric muscle weakness and difficulty weaning from the ventilator. Mild, generalized weakness (eg, bilateral decreased grip strength) from muscle disuse is common in bedbound, hospitalized patients such as this one. (Choice F) Vasopressor extravasation would be expected to cause local vasoconstrictive effects (eg, venous blanching, pallor of surrounding tissues) but would not explain isolated median nerve deficits; in addition, vasopressor therapy is typically infused via a central venous rather than an arterial catheter. Educational objective: Because the median nerve lies directly adjacent to the brachial artery in the distal upper arm, it can be injured (eg, laceration, compression) as a result of brachial artery cannulation. References: Relationship of the median and radial nerves at the elbow: application to avoiding injury during venipuncture or other invasive procedures of the cubital fossa. (http://www.ncbi.nlm.nih.gov/pubmed/28413740) Complications from brachial arterial pressure monitoring are rare in patients having cardiac surgery. (http://www.ncbi.nlm.nih.gov/pubmed/29608204)

A 72-Year-Old Hospitalized Man Is Evaluated for New-Onset Paresthesia in the Right