Differential Effects of Vecuronium on Diaphragm and Geniohyoid Muscle in Anaesthetized Dogs

Abstract

We have examined the sensitivity of the geniohyoid, an upper airway dilating muscle, to vecuronium in 12 anaesthetized dogs undergoing mechanical ventilation of the lungs and compared it with that of the diaphragm. Dogs were allocated randomly to two groups: pentobarbitone alone (group 1, n = 7); pentobarbitone combined with 0.2 MAC (0.44%) of enflurane anaesthesia (group 2, n = 5). Supramaximal single twitch stimulations (0.1 Hz) were applied to the phrenic nerves in the upper thorax and the geniohyoid branches of the hypoglossal nerves at the neck. The evoked responses were assessed by the transdiaphragmatic pressure (Pdi) and the isometric force of the geniohyoid muscles (Tgh) until complete recovery of these variables after i.v. administration of vecuronium 0.02 mg kg-1. In both groups, the magnitude of the depression of twitch response was greater and time required to reach control amplitude was longer in the geniohyoid than the diaphragm. The depression of Tgh was significantly greater in group 2 than in group 1, whereas no change was observed in Pdi between the two groups. We conclude that the geniohyoid is more sensitive to vecuronium than the diaphragm and the differential effects of vecuronium are facilitated by a low concentration of enflurane.

Rocuronium pharmacokinetics and pharmacodynamics in the adductor pollicis and masseter muscles

“…[1][2][3][4][5] The masseter, genioglossus, and geniohyoid are upper airway muscles that play an important role in airway patency. It has been suggested that while inspiratory muscles have recovered their function, upper airway muscles may still be paralyzed predisposing to airway collapse at the end of anesthesia 6 . A previous study by D'Honneur and colleagues compared the effect of atracurium and vecuronium on the adductor pollicis muscle and the geniohyoid muscle in 16 patients.…”

Postoperative complications in patients with obstructive sleep apnea: a retrospective matched cohort study

“…13 Physiological studies show that the upper airway muscles are more sensitive to neuromuscular blocking drugs than either the diaphragm or the peripheral muscles. 14 Patients with OSA are highly vulnerable to medications that suppress pharyngeal muscle activity. [15][16][17] In addition to compromising upper airway muscle function, general anesthesia and narcotics can depress the patients' ventilatory responses to obstruction and inhibit their normal arousal and awakening responses to hypoxia and hypercapnia.…”

Impaired Upper Airway Integrity by Residual Neuromuscular Blockade: Increased Airway Collapsibility and Blunted Genioglossus Muscle Activity in Response to Negative Pharyngeal Pressure

“…The upper airway dilator muscles deliver these dilating forces, but it is largely unknown whether this balance is maintained during recovery from neuromuscular blockade. It has been shown in animals 21,23 and in humans 10,11 that up-per airway muscles are more susceptible to effects of neuromuscular blocking agents than the diaphragm. 11,21,23 Sundman and Eriksson 10 showed an increased incidence of misdirected swallowing and a decreased upper esophageal sphincter resting tone during minimal neuromuscular blockade (TOF ratio 0.5-1) that persisted even with recovery of the TOF ratio to unity.…”