吸入不同浓度氧化亚氮对全麻患者双腔喉罩囊内压的影响

目的 评价吸入不同浓度氧化亚氮对全麻患者双腔喉罩囊内压的影响.方法 择期全麻患者48例,ASAⅠ或Ⅱ级,年龄25～64岁,随机分为4组(n=12):C组、N1组、N2组及N3组.根据患者身高和体重选择合适型号的双腔喉罩.依次静脉注射异丙酚、瑞芬太尼、利多卡因及维库溴铵行麻醉诱导,喉罩置入成功后,套囊内注入空气,调节囊内压使其达加cm H2O(基础值),连接麻醉机行机械通气,C组、N1组、N2组及N3组分别吸入100%O2、65%O2+35%N2O、50%O2+50%N2O及35%O2+65%N2O,于吸入15、30、45、60、75、90 min时(T1-6)测定喉罩囊内压.结果 与C组比较,N1-3组T1-6时囊内压升高;与N1组比较,N2,3组T1-6时囊内压升高;与N2组比较,N3组,T1-6时囊内压升高(P<0.05).与T0时比较,C组T2-6时囊内压降低,N1组T2-6时囊内压升高,N2,3组T1-6时囊内压升高(P<0.05).N1-3组囊内压与吸入时间呈正相关(相关系数分别为0.968、0.987、0.973,P<0.05).结论 吸入N2O可使喉罩囊内压升高,呈浓度及时间依赖性.

Effects of inhalation of different concentrations of nitrous oxide on intracuff pressure of the laryngeal mask airway in patients during general anesthesia

Objective To investigate the effects of inhalation of different concentrations of nitrous oxide on intracuff pressure (ICP) of the laryngeal mask airway (LMA) in patients during general anesthesia. Methods Forty-right ASA Ⅰ or Ⅱ patients aged 25-64 yr undergoing elective operations under general anesthesia were randomly divided into 4 groups (n=12 each): group C (100 %O2, group N2 (65 % O2 + 35%N2O), group N2 (50%O2 + 50 % N2O), and group N3 (35%O2 + 65%N2O). A suitable model of the LMA was selected according to height and weight. Anesthesia was induced with Ⅳ propofol 1.5-2.0 mg/kg, fentanyl 2-3 μg/kg, lidocaine 1-2 mg/kg and vecuronium 0.08-0.1 mg/kg and maintained with intravenous infusion of propofol and intermittent boluses of fentanyl and vecuronium. After the successful placement of LMA, the air was injected into the cuff to make intracuff pressure (ICP) reach 40 cm H2O (baseline). The ICP were recorded at 15, 30, 45, 60, 75 and 90 min (T1-6) following inhalation of N2O. Results The ICP grandually increased with the increase in the concentration of N2O (P<0.05). The ICP decreased at T2-6 in group C, but increased at T2-6 in group N1 and at T1-6 in group N2,3 as compared with baseline(P<0.05). There was a positive correlation between the ICP and inhalation time in group N1-3(r1-3=0.968,0.987,0.973 respectively, P<0.05). Conclusion The inhalation of N2O can increase the ICP in concentration- and time-dependent manners,