Background: The ventilatory response to hypoxia is a life-saving chemoreflex
originating at the carotid bodies that is impaired by nondepolarizing
neuromuscular blocking agents. This study evaluated the effect of three strategies
for reversal of a partial neuromuscular block on ventilatory control in
34 healthy male volunteers on the chemoreflex. The hypothesis was that the
hypoxic ventilatory response is fully restored following the return to a trainof-
four ratio of 1.
Methods: In this single-center, experimental, randomized, controlled trial,
ventilatory responses to 5-min hypoxia (oxygen saturation, 80 ± 2%) and ventilation
at hyperoxic isohypercapnia (end-tidal carbon dioxide concentration,
55 mmHg) were obtained at baseline, during rocuronium-induced partial neuromuscular
block (train-of...
Show moreBackground: The ventilatory response to hypoxia is a life-saving chemoreflex
originating at the carotid bodies that is impaired by nondepolarizing
neuromuscular blocking agents. This study evaluated the effect of three strategies
for reversal of a partial neuromuscular block on ventilatory control in
34 healthy male volunteers on the chemoreflex. The hypothesis was that the
hypoxic ventilatory response is fully restored following the return to a trainof-
four ratio of 1.
Methods: In this single-center, experimental, randomized, controlled trial,
ventilatory responses to 5-min hypoxia (oxygen saturation, 80 ± 2%) and ventilation
at hyperoxic isohypercapnia (end-tidal carbon dioxide concentration,
55 mmHg) were obtained at baseline, during rocuronium-induced partial neuromuscular
block (train-of-four ratio of 0.7 measured at the adductor pollicis
muscle by electromyography), and following reversal until the train-of-four
ratio reached unity with placebo (n = 12), 1 mg neostigmine/0.5 mg atropine
(n = 11), or 2 mg/kg sugammadex (n = 11).
Results: This study confirmed that low-dose rocuronium reduced the ventilatory
response to hypoxia from 0.55 ± 0.22 (baseline) to 0.31 ± 0.21 l ·
min−1 · %−1 (train-of-four ratio, 0.7; P < 0.001). Following full reversal as
measured at the thumb, there was persistent residual blunting of the hypoxic
ventilatory response (0.45 ± 0.16 l · min−1 · %−1; train-of-four ratio, 1.0;
P < 0.001). Treatment effect was not significant (analysis of covariance,
P = 0.299) with chemoreflex impairment in 5 (45%) subjects following sugammadex
reversal, in 7 subjects (64%) following neostigmine reversal, and in 10
subjects (83%) after spontaneous reversal to a train-of-four ratio of 1.
Conclusions: Despite full reversal of partial neuromuscular block at the
thumb, impairment of the peripheral chemoreflex may persist at train-of-four
ratios greater than 0.9 following reversal with neostigmine and sugammadex
or spontaneous recovery of the neuromuscular block.
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