Hypoxic ventilatory response after rocuronium-induced partial neuromuscular blockade in men with obstructive sleep apnoea

Obstructive sleep apnoea and residual neuromuscular blockade are, independently, known to be risk factors for respiratory complications after major surgery. Residual effects of neuromuscular blocking agents are known to reduce the hypoxic ventilatory response in healthy volunteers. Patients with obstructive sleep apnoea have impaired control of breathing, but it is not known to what extent neuromuscular blocking agents interfere with the regulation of breathing in such patients. In a physiological study in 10 unsedated men with untreated obstructive sleep apnoea, we wished to examine if partial neuromuscular blockade had an effect on hypoxic ventilatory response (isocapnic hypoxia to oxygen saturation of 80%) and hypercapnic ventilatory response (normoxic inspired carbon dioxide 5%). The hypoxic ventilatory response was reduced by 32% (p = 0.016) during residual neuromuscular block (rocuronium to train-of-four ratio 0.7), but the hypercapnic ventilatory response was unaffected. We conclude that neuromuscular blockade specifically depresses peripheral chemosensitivity, and not respiratory muscle function since the hypercapnic ventilatory response was unaffected.