Comparison of pressure support ventilation and pressure control ventilation in children receiving short-term minor laparoscopic surgery

Abstract

Objective To determine the efficacy of pressure support ventilation (PSV) in children receiving short-term minor laparoscopic surgery under general anesthesia.Methods Sixty children with American Society of Anesthesiology (ASA) stage Ⅰ (age:3-11 years,weight:14-40 kg) scheduled for laparoscopic hernia repair between February 2011 and December 2012 were randomly assigned to pressure control ventilation (PCV) group (group C,n=30) and PSV group (group S,n=30),respectively.Anesthesia was induced with fentanyl 2 μg/kg,propofol 2 mg/kg and scoline 1.5 mg/kg.This was followed by endotracheal intubation and maintenance anesthesia with sevoflurane,with the end-expiratory concentration corresponding to 1.3-1.5 minimal alveolar concentration.Children in group C received PCV till extubation,with an end-expiratory partial pressure of carbon dioxide (PETCO2) retained at 35-45 mm Hg (1 mm Hg=0.133 kPa).This was followed by intravenous injection of cis-atracurium bensylate (0.1 mg/kg) for muscular relaxation when spontaneous breathing commenced.Children in group S were treated with PCV till extubation by maintaining the PETCO2 at 35-45 mm Hg.This was followed by translation from PCV to PSV upon initiation of spontaneous breathing.Injection of additional muscle relaxant was spared.Anesthesia with sevoflurane was ceased upon cessation of artificial pneumoperitoneum in both groups.The mean arterial blood pressure (MBP) and heart rate (HR) were recorded before induction of anesthesia (T0),at the end of intubation (T1),at the commencement of pneumoperitoneum (T2),at 5 min following pneumoperitoneum (T3),at 10 min following pneumoperitoneum (T4),upon cessation of pneumoperitoneum (T5),upon cessation of operation (T6) and during extubation (T7) respectively.The time for surgery and tracheal extubation was recorded.Results The difference in MBP and HR between baseline level (T0) and T1-T6 was unremarkable,with exception of significantly increased at T7 in group C (both P＜0.05).Compared with baseline level (T0),the difference in MBP and HR at all time points (T1-T7) did not reach statistical significance in group S.MBP and HR were not statistically different between the two groups,with exception of markedly increased MBP and HR at T7 in group C compared with group S (both P＜0.05).Time of extubation in group C was longer compared with group S [(23±5)min vs (6±2)min,P＜0.05].Conclusion Characterized by reduced time to extubation and minor cardiovascular reactions,PSV may waive the need of additional long-acting muscle relaxants and is suitable for children receiving short-term minor laparoscopic surgery. Key words: Pressure support ventilation; Pressure control ventilation ; Children; Laparoscope