Neuromuscular blockade resistance during therapeutic hypothermia.

ABSTRACT

OBJECTIVE: To report a case of neuromuscular blockade resistance to multiple agents during therapeutic hypothermia and discuss possible mechanisms of this resistance. CASE SUMMARY: A 64-year-old man with stage IV non-small-cell lung cancer and respiratory distress developed cardiac arrest in the emergency department. The man was quickly resuscitated and treated with therapeutic hypothermia. A chest tube was inserted for pleural drainage of a large right-sided effusion that collapsed the right lung; this was unsuccessful in reinflating the lung. A bronchopleural fistula developed and independent lung ventilation was initiated due to persistent hypoxemia. Neuromuscular blockade was initiated after sedation and analgesia did not control shivering and was continued due to patient-ventilator dyssynchrony and persistent hypoxemia. Despite large doses of 3 different neuromuscular blocking agents and negligible response to train-of-four tests, clinical neuromuscular blockade, represented by ventilator synchrony, was not achieved until the patient was warmed. DISCUSSION: Resistance to neuromuscular blocking agents has been reported in critically ill patients. Our case of neuromuscular blockade resistance occurred in a patient treated with therapeutic hypothermia, which generally requires a dose reduction of neuromuscular blocking agents. Resistance to neuromuscular blockade was quickly reversed upon warming of the patient as patient-ventilator synchrony was achieved at lower neuromuscular blocking agent doses. CONCLUSIONS: Clinicians should be aware of a potential blunted response to neuromuscular blocking agents during therapeutic hypothermia and difficulty with paralysis monitoring since train-of-four response may correlate poorly with clinical neuromuscular blockade during hypothermia. Further research is needed to elucidate the mechanism of this interaction, identify patients at risk, and evaluate alternative strategies to neuromuscular blockade for controlling shivering in patients undergoing therapeutic hypothermia.