滴定个体化呼气末正压对全麻俯卧位脊柱手术老年患者呼吸功能的影响

Effect of titration method on individualized positive end-expiratory pressure in elderly patients undergoing spinal surgery in prone position under general anesthesia

目的探讨滴定个体化呼气末正压(PEEP)对全麻俯卧位脊柱手术老年患者术中呼吸和循环的影响。方法选择择期全麻下行俯卧位脊柱手术老年患者80例,男39例,女41例,年龄≥65岁,ASAⅡ或Ⅲ级。根据术中是否滴定获取个体化PEEP将患者随机分为两组:滴定组和对照组,每组40例。滴定组从0 cmH_(2)O开始递增至20 cmH_(2)O,PEEP变化梯度为2 cmH_(2)O获取个体化PEEP;对照组PEEP恒定为5 cmH_(2)O并通气至手术结束。记录滴定过程中每个PEEP水平持续1 min时动态肺顺应性(Cdyn),将Cdyn最大时的PEEP定为个体化PEEP。记录俯卧位时(T_(0))、PEEP通气10 min(T_(1))、30 min(T_(2))、60 min(T_(3))、手术结束(T_(4))、拔管后20 min(T_(5))的MAP、HR、CVP,记录T_(0)—T_(4)时平均气道压(Pmean)和Cdyn。T_(0)—T_(5)时行血气分析,计算肺内分流率(Qs/Qt)和氧合指数(OI)。记录机械通气过程中去氧肾上腺素使用和术后肺部并发症情况。结果滴定组所获取的个体化PEEP为(12.38±2.67)cmH_(2)O。T_(0)—T_(5)时两组MAP、HR、CVP差异无统计学意义。T_(0)—T_(4)时两组Pmean差异无统计学意义。T_(2)—T_(4)时滴定组Cdyn明显高于对照组(P<0.05),Qs/Qt明显低于对照组(P<0.05)。T_(2)—T_(5)时滴定组OI明显高于对照组(P<0.05)。滴定组去氧肾上腺素使用率明显高于对照组[10例(25%)vs 3例(8%),P<0.05]。滴定组术后肺部并发症发生率明显低于对照组[2例(5%)vs 8例(20%),P<0.05]。结论与恒定PEEP 5 cmH_(2)O比较,俯卧位脊柱手术老年患者术中滴定个体化PEEP,能够更好地改善氧合,降低肺内分流率,减少术后肺部并发症。

Objective To explore the effect of titration of individualized positive end-expiratory pressure(PEEP)on the respiration and circulation of elderly patients undergoing prone spine surgery under general anesthesia.Methods Eighty patients undergoing spinal surgery in prone position under general anesthesia,39 males and 41 females,aged≥65 years,ASA physical status Ⅱ or Ⅲ,were included in this study.According to the intraoperative titration increment to obtain individualized PEEP,the patients were randomly divided into titration group and control group,with 40 patients in each group.In the titration group,the titration method of PEEP started from 0 cmH_(2)O and increased to 20 cmH_(2)O.PEEP of the control group was constant at 5 cmH_(2)O and ventilated to the end of the operation.The gradient of change in PEEP during titration was 2 cmH_(2)O in all patients.The dynamic pulmonary compliance(Cdyn)of end-expiration displayed by the anesthesia machine was recorded at 1 min of each PEEP level during the titration,and the PEEP at the maximum Cdyn was set as the individualized PEEP obtained by the titration method.MAP,HR,and CVP were recorded in the prone position(T_(0)),individualized PEEP ventilation for 10 minutes(T_(1)),30 minutes(T_(2)),60 minutes(T_(3)),the end of the operation(T_(4)),and 20 minutes after extubation(T_(5)).The mean airway pressure(Pmean)and Cdyn were recorded at T_(0)-T_(4).Blood gas analysis was performed at T_(0)-T_(5) to calculate the intrapulmonary shunt rate(Qs/Qt)and OI(PaO 2/FiO 2).The number of phenylephrine use and postoperative pulmonary complications during mechanical ventilation were recorded.Results The individualized PEEP obtained by titration in the titration group were(12.38±2.67)cm H_(2)O.There were no statistically significant differences in MAP,HR,and CVP between the two groups at T_(0)-T_(5).There was no significant difference in Pmean between the two groups at T_(0)-T_(4).Cdyn in the titration group was significantly higher than that in the control group at T_(2)-T_(4)(P<0.05),and Qs/Qt in the titration group was significantly lower than that in the control group at T_(2)-T_(4)(P<0.05).OI in the titration group was significantly higher than that in the control group at T_(2)-T_(5)(P<0.05).The use rate of phenylephrine in the titration group was significantly higher than that in the control group[10 patients(25%)vs 3 patients(8%),P<0.05].The incidence of postoperative pulmonary complications in the titration group was significantly lower than that in the control group[2 patients(5%)vs 8 patients(20%),P<0.05].Conclusion Individualized PEEP in elderly patients undergoing prone spine surgery improves oxygenation,reduces intrapulmonary shunt rate and postoperative pulmonary complications compared with a constant PEEP 5 cmH_(2)O.