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

Focus on one contradiction in the vignette. The woman is fully awake and aware, but her chest and upper body barely move and she cannot breathe well on her own. Her heart rate and blood pressure are fine.

If the problem were the opioid itself, fentanyl would have dulled her consciousness, yet she is alert, so deep opioid respiratory depression does not fit. Fentanyl chest wall rigidity is a real event, but it strikes during induction while the patient is anaesthetised, not in the recovery room after extubation. A pulmonary embolus would knock her vitals around with a fast heart and falling pressure, which is not described.

The one diagnosis that explains an awake brain sitting on top of weak muscles is leftover muscle relaxant. Pancuronium is long lasting and depends on the kidneys, and in an overweight patient its recovery is hard to predict. If reversal was incomplete, she stays conscious but cannot move her respiratory muscles properly.

That is residual neuromuscular blockade.

\[\boxed{\text{Incomplete reversal of pancuronium}}\]