Question

A 25 year old overweight female was given fentanyl-pancuronium anaesthesia for surgery. After surgery and extubation she was observed to have limited movement of the upper body and chest wall in the recovery room. She was conscious and alert but voluntary respiratory effort was limited. Her blood pressure and heart rate were normal. The likely diagnosis is:

• A. Incomplete reversal of pancuronium
• B. Pulmonary embolism
• C. Fentanyl induced chest wall rigidity
• D. Respiratory depression

Hint:

Awake and alert but weak breathing points to leftover muscle relaxant, not the opioid.

Answer 1

The Correct Option is A

Step 1: Identify the key findings. The patient is conscious and alert, so the brain is awake, yet she cannot move her upper body and chest wall and her voluntary respiratory effort is weak. Vital signs are normal.

Step 2: Awake but weak muscles is the signature of residual neuromuscular block. A patient with leftover pancuronium can be fully conscious but unable to generate adequate muscle power, including for breathing.

Step 3: Pancuronium is long acting and largely renally cleared. In an overweight patient, dosing and recovery can be unpredictable, making incomplete reversal common, especially if reversal was inadequate.

Step 4: Exclude the distractors. Fentanyl induced chest wall rigidity occurs during induction when the patient is anaesthetised, not after extubation in an awake patient. Pulmonary embolism would cause tachycardia, hypotension and hypoxia, but her vitals are normal. Pure opioid respiratory depression would reduce alertness, yet she is conscious and alert.

Step 5: The combination of full consciousness with weak respiratory muscles fits residual paralysis.

The answer is A. Incomplete reversal of pancuronium.