TOF count at corrugator supercilii reflects abdominal muscles relaxation better than at adductor pollicis.
BACKGROUND
A recovery profile from neuromuscular block similar to that of abdominal (AB) muscles, but different to that of the adductor pollicis (AP) muscle, has been demonstrated at the corrugator supercilii (CSC) muscle. We hypothesized that neuromuscular transmission (NMT) monitoring of CSC might provide useful information on AB relaxation compared with AP. We compared the visual estimation of NMT at CSC and AP with electromyographic measurements of AB during recovery from a vecuronium block.


METHODS
Ten adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agents, supramaximal stimulations were applied to three nerves: left 10th intercostal, ulnar, and facial. Electromyographic activity (EMG) of AB was measured (ABemg). After a bolus dose of vecuronium 0.1 mg kg-1, an independent observer blinded to the EMG measurements counted visually detectable train-of-four (TOF) responses at CSC and AP. Values of ABemg associated with 1 to 4 TOF responses at CSC and AP were compared. Values are means (sd).


RESULTS
Reappearance of the first and second TOF responses at CSC occurred significantly (P<0.05) earlier and at lower ABemg recovery than that of AP [35 (8) and 41 (9) min vs 51 (10) and 56 (12) min; and 17 (8) and 26 (9)% vs 56 (10) and 75 (11)%, respectively].


CONCLUSIONS
We demonstrated that the TOF response count at the CSC, compared with the AP, allowed a better quantification of the degree of AB muscle relaxation during recovery from vecuronium block.
Kirov
K
K
Anaesthesia and Intensive Care Department, Jean Verdier University Hospital of Paris, 93143 Bondy Cedex, France.
Motamed
C
C
Ndoko
S-K
SK
Dhonneur
G
G
D000009:Abdominal Muscles / Q000187:drug effects* / Q000502:physiology; D000328:Adult; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D004311:Double-Blind Method; D004558:Electric Stimulation; D004576:Electromyography / Q000187:drug effects / Q000379:methods; D005138:Eyebrows / Q000502:physiology; D005152:Facial Muscles / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D009126:Muscle Relaxation / Q000187:drug effects*; D019148:Neuromuscular Blockade; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D014673:Vecuronium Bromide / Q000494:pharmacology*
D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide