Background and Goal of Study: The aim of the study was to evaluate the depth of neuromuscular blockade requested for laparoscopic gastroplasty.
Materials and Methods: Target-controlled propofol and sufentanil infusions were administered to 12 morbidly obese patients (body mass index: 42.5 [41.8-44.5] kg/m2). The target plasma propofol concentration was 3 to 4 μg/ml whereas the sufentanil infusion rate was 0.2 to 0.4 μg/kg/h adusted on blood pressure and heart rate. A bolus dose of atracurium (0.5 mg/kg) was given intravenously after onset of unconsciousness to facilitate tracheal intubation. Additional atracurium bolus (0.2 mg/kg) was given when inadequate surgical field was observed by the surgeon (JMC) who was blinded for the depth of neuromuscular blockade. The depth of neuromuscular blockade was monitored by using peripheral nerve stimulator. The evoked response to the train-of-four (TOF) stimulation was measured by acceleromyography at the adductor pollicis (AP) and the corrugator supercilii (CS). A post tetanic count (PTC) was measured at the AP when the recovery of the first response to CS TOF was done. Results were given as median [interquartil 25-75].
Results and Discussions: The characteristics of the patients were age 43 [31-48] yrs; women 75%; ASA 2 [1-2]. The surgical procedure lasted 125 [99-139] min. After 0.5 mg/kg atracurium, time to obtain 0 response to TOF at the CS was 135 [120-135] seconds. Twenty two atracurium bolus were given according to the surgical demands: 0 in two patients, 1 in three patients and ≥2 in seven patients. Seventeen (77%) demands occurred whereas less than 2 responses to TOF at AP were observed. No demand occurred before the recovery of 2 responses to TOF at the CS. The recovery of the 1 response to TOF at CS corresponded to 2 [1-3] responses to PTC at AP.
Conclusion(s): Based on the surgical demand, the majority of the patients needed atracurium bolus during laparoscopic gastroplasty. The TOF at AP did not allow to anticipate the surgical demand. The TOF at the CS and/or the PTC at the AP were more adapted to the surgical demand.