Visual evaluation of residual curarization in anesthetized patients using one hundred-hertz, five-second tetanic stimulation at the adductor pollicis muscle

• Published in: Anesthesia and analgesia Vol. 87; no. 1; pp. 185 - 189
• Main Authors: BAURAIN, M. J, HENNART, D. A, GODSCHALX, A, HUYBRECHTS, I, NASRALLAH, G, D'HOLLANDER, A. A, CANTRAINE, F
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott 01.07.1998
• Subjects: Adult; Anesthesia; Anesthesia, General - methods; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Atracurium; Biological and medical sciences; Electric Stimulation; General anesthesia. Technics. Complications. Neuromuscular blocking. Premedication. Surgical preparation. Sedation; Humans; Isometric Contraction - drug effects; Isometric Contraction - physiology; Medical sciences; Middle Aged; Muscle, Skeletal - drug effects; Muscle, Skeletal - innervation; Neuromuscular Nondepolarizing Agents; Ulnar Nerve - drug effects; Ulnar Nerve - physiology; Vecuronium Bromide; Atracurium besilate; Human; Steroid; Non depolarisant myorelaxant; Adductor pollicis muscle; Surveillance; Electrical stimulus; General anesthesia; Neuromuscular transmission; Vecuronium bromide; Neuromuscular blocking; Monitoring
• ISSN: 0003-2999; 1526-7598
• DOI: 10.1097/00000539-199807000-00038

We were looking for a clinical test to indicate a train-of-four (TOF) ratio of approximately 0.9. We compared the adductor pollicis muscle (AP) visually evaluated response to ulnar nerve 100-Hz, 5-s tetanus (RF100 Hz) with the measured AP TOF ratio in 30 ASA physical status I or II adult anesthetized (propofol, sufentanil, N2O/O2) patients. After the induction of anesthesia, the left ulnar nerve was stimulated at the wrist (single twitch and TOF) and the resultant isometric force was measured. When TOF was assessed, the independent investigators, unaware of the left AP-measured TOF ratios, visually evaluated the presence or absence of AP fading elicited by right ulnar nerve 100-Hz, 5-s tetanus. The 30 patients were randomly allocated to receive either 0.5 mg/kg atracurium (n = 15) or 0.1 mg/kg vecuronium (n = 15). The neuromuscular blockade was allowed to resolve spontaneously. A multiple logistic regression analysis was performed by computing the 771 visual observations. The probabilities of success of 100-Hz, 5-s tetanus to detect TOF ratios of 0.8, 0.85, and 0.9 were 99%, 96%, and 67%, respectively. The sensitivity and specificity of 100-Hz, 5-s tetanus as an indicator of TOF ratios of 0.85 and 0.9 are 100% and 75%, 54% and 67%, respectively. We conclude that RF100 Hz visual assessment seems to be highly sensitive in evaluating residual paralysis, as the absence of RF100 Hz visual fading at the AP is compatible with a TOF ratio > 0.85. After the administration of muscle relaxants, the absence of visual fading at the adductor pollicis, elicited in anesthetized patients by 100-Hz, 5-s tetanus, is compatible with a train-of four ratio > 0.85. Therefore, clinical observation of fading after 100-Hz, 5-s tetanus seems to be a highly sensitive test in evaluating residual paralysis.