Recovery from rocuronium-induced neuromuscular block was longer in the larynx than in the pelvic limb of anesthetized dogs

• Published in: Veterinary anaesthesia and analgesia Vol. 44; no. 2; p. 246
• Main Authors: Sakai, Daniel M, Martin-Flores, Manuel, Romano, Marta, Tseng, Chia T, Campoy, Luis, Gleed, Robin D, Cheetham, Jonathan
• Format: Journal Article
• Language: English
• Published: United States 01-03-2017
• Subjects: Androstanols; Animals; Dogs; Larynx - drug effects; Larynx - physiology; Neuromuscular Blockade - methods; Neuromuscular Blockade - veterinary; Neuromuscular Nondepolarizing Agents; Pelvis - innervation; Prospective Studies; Synaptic Transmission - drug effects; Synaptic Transmission - physiology; airway obstruction; complication; monitoring; residual paralysis; aspiration
• ISSN: 1467-2995
• DOI: 10.1016/j.vaa.2016.04.001

To determine if neuromuscular monitoring at the pelvic limb accurately reflects neuromuscular function in the larynx after administration of rocuronium in anesthetized dogs.
Prospective experimental study.
Six healthy Beagle dogs.
Anesthesia was maintained in dogs with isoflurane and a continuous infusion of dexmedetomidine. Rocuronium (0.6 mg kg
) was administered intravenously to induce neuromuscular block. Train-of-four (TOF) impulses were applied to the left recurrent laryngeal nerve (RLn) and the peroneal nerve (Pn). The evoked TOF ratio (TOFR; T4:T1) was measured with electromyography (EMG) simultaneously at the larynx and at the pelvic limb. Spontaneous recoveries of T1 to 25% (T1
) and 75% (T1
) of twitch height, and to TOFR of 0.70 and 0.90 (TOFR
) at each EMG site were compared.
Data from five dogs were analyzed. Times to T1
were similar at the pelvic limb and larynx when measured by EMG; time to T1
was slower at the larynx by 6±4 minutes (p=0.012). The larynx had a slower recovery to TOFR
(41±13 minutes) and TOFR
(45±13 minutes) than did the pelvic limb [29±8 minutes (p=0.011) and 33±9 minutes (p=0.003), respectively]. When the pelvic limb EMG returned to TOFR
and TOFR
, the larynx EMG TOFR
and TOFR
values were 0.32±0.12 (p=0.001) and 0.38±0.13 (p=0.001), respectively.
After administration of rocuronium, neuromuscular function assessed by EMG recovered approximately 36% slower at the larynx than at the pelvic limb. The results in these dogs suggest that quantitative neuromuscular monitoring instrumented at a pelvic limb may be unable to exclude residual block at the larynx in anesthetized dogs.