Reduced hypoxic chemosensitivity in partially paralysed man. A new property of muscle relaxants?

BACKGROUND: It was hypothesized that non-depolarizing neuromuscular blocking agents impair hypoxic chemosensitivity in man. METHODS: In thirty randomly allocated male volunteers the hypoxic and hypercarbic ventilatory responses were measured during partial paralysis (TOF ratio 0.70) due to either atracurium (n = 10), pancuronium (n = 10) or vecuronium (n = 10). RESULTS: Hypoxic ventilatory responses were depressed by 306, 287 and 296% (mean SD) at steady-state infusion of atracurium, pancuronium and vecuronium, respectively. At a TOF ratio of > 0.90, the HVR was not different from control measurements. CONCLUSION: It is concluded that non-depolarizing neuromuscular blocking agents impair hypoxic ventilatory regulation. Further experimental studies are warranted to fully describe the mechanism(s) responsible for this interaction.