Efficacy of pressure support ventilation in infants undergoing laparoscopic hernia repair under sevoflurane anesthesia

Objective To evaluate the efficacy of pressure support ventilation (PSV) in the infants undergoing laparoscopic hernia repair under sevoflurane anesthesia. Methods Thirty ASA physical status Ⅰ pediatric children, aged 9 months-1 yr, weighing 8.0-11.5 kg, undergoing elective laparoscopic hernia repair, were randomly assigned into 3 groups (n=10 each) using a random number table: pressure control ventilation (PCV) used for muscle relaxants in combination with low-concentration sevoflurane group (group PCV1) , PCV used for high-concentration sevoflurane group (group PCV2) , and PSV used for low-concentration sevoflurane group (group PSV) . Anesthesia was induced with inhalation of 4%-6% sevoflurane and iv fentanyl 2 μg/kg and succinylcholine 1.5 mg/kg.The pediatric children were endotracheally intubated and mechanically ventilated.In PCV1 and PCV2 groups, PCV was used during operation.In group PSV, PCV was used first after intubation, and then PSV was applied after spontaneous breathing recovered.Anesthesia was maintained as follows: in group PCV1, the end-tidal concentration of sevoflurane was maintained at 2.5%-3.0%, and cisatracurium besylate 0.1 mg/kg was injected intermittently as required; in group PCV1, the end-tidal concentration of sevoflurane was maintained at 3.5%-4.0%; in group PSV, the end-tidal concentration of sevoflurane was maintained at 2.5%-3.0%, and succinylcholine 1.0 mg/kg was injected intravenously before pneumoperitoneum.Narcotrend index value was maintained at 50-60 in PCV1 and PSV groups, or at 37-45 in PCV2 group.Heart rate (HR) and mean arterial pressure (MAP) were recorded before induction of anesthesia (baseline) , at the beginning of pneumoperitoneum, at 5 and 10 min of pneumoperitoneum, at the end of pneumoperitoneum, at the end of operation and immediately after extubation.The time interval from the end of surgery to extubation was recorded. Results Pulse oxygen saturation was 100% during anesthesia, and>95% during recovery from anesthesia in the three groups.Compared with the baseline value, HR was significantly faster, and MAP was increased during extubation in PCV1 and PCV2 groups, and no significant change was found in HR and MAP at each time point in group PSV.The time interval from the end of surgery to extubation was 30.3±5.4, 18.4±4.3 and (4.1±1.2) min in PCV1, PCV2 and PSV groups, respectively.Compared with PCV1 and PCV2 groups, the time interval from the end of surgery to extubation was significantly shortened in group PSV. Conclusion When PSV is applied in the infants undergoing laparoscopic hernia repair under sevoflurane anesthesia, it can provide adequate ventilation, recovery from anesthesia is rapid, and no cardiovascular responses occur during extubation. Key words: Anesthetics, inhalation; Anesthesia, general; Infant; Laparoscopy; Pressure support ventilation