无创正压通气在心外科术后患者中的应用

目的:回顾性研究无创正压通气(NPPV)对心外科体外循环(CPB)术后出现急性呼吸衰竭(ARF)患者的安全性和有效性。方法:回顾本院心外科全麻CPB术后成年患者(年龄>16岁)450例,其中24例在拔管后出现ARF,根据ARF的病因分为6例肺炎、7例心源性肺水肿、11例CPB相关性肺损伤,比较NPPV使用前、后1h的氧合指数、心率、呼吸次数和动脉血pH,并用患者围手术期的临床特征作为参数来分析NPPV失败的预测因素。结果:NPPV平均使用时间(12.33±11.97)h,氧合指数、心率、呼吸次数和动脉血pH在使用前、后1h均明显改善(均P<0.01)。NPPV使66.67%的患者避免再次气管插管,其中对心源性肺水肿和CPB相关性肺损伤的疗效满意,成功率分别是85.71%和90.91%;而肺炎的患者均失败。所有患者均无NPPV并发症。有意义的单因素预测因素是NPPV治疗后1h的PaO2/FiO2<200,初次机械通气的时间和肺炎,多因素分析显示肺炎是预测NPPV失败的独立因素(OR0.063;95%CI 0.008～0.501)。结论:心外科CPB术后患者拔管后出现ARF,NPPV可以有效改善肺部氧合,减低再次气管插管的需要,但要严格选择病例。

An observation of noninvasive positive-pressure ventilation after cardiac surgery

Objective:We conducted a retrospective cohort study to investigate the efficacy and safety of noninvasive positive pressure ventilation(NPPV) for acute respiratory failure(ARF) in patients undergoing cardiac surgery. Method:We obtained a first cohort of 450 adult patients(age>16 years) who underwent cardiac surgery with cardiopulmonary bypass between January 2010 and August 2010.24 patients with ARF were treated with NPPV.The cause of ARF was classified as pneumonia in 6 patients,cardiogenic edema in 7 patients,and post-cardiopulmonary bypass lung injury in 11 patients.Oxygenation Index,heart rate,respiratory rate,PH value of arterial blood and perioperative patient characteristics before and 1h after NPPV treatment were evaluated as predictors of NPPV failure. Result:The mean length of NPPV support was(12.33±11.97) hours.Compared with baseline,NPPV treatment was associated with a significant increase in the PaO2/FiO2 ratio [(118.00±11.80)∶(245.17±67.71),P<0.01] and arterisl pH levels [(7.37±0.08)∶(7.40±0.06),P<0.01],a significant decrease in respiratory rate [(42.33±9.80)∶(22.25±10.69),P<0.01] and heart rate [(123.50±13.46)∶(96.75±15.19),P<0.01].NPPV prevented intubation in 66.67% of the patients,with satisfactory recovery for cardiogenic dysfunction and CPB lung injury(85.71% and 90.91%,respectively) and poor results in those treated for pneumonia.NPPV safety approached 100%.On a univariate analysis,the PaO2/FiO2 ratio less than 200 after 1 h of NPPV,duration of initial mechanical ventilation and underlying respiratory failure cause were associated with NPPV failure.In a multivariate analysis,pneumonia was an independent predictive factor of NPPV failure(OR 0.063;95%CI 0.008-0.501). Conclusion:NPPV could be considered in postoperative patients who presented with ARF,avoiding tracheal intubation in some patients.If ARF is associated with pneumonia,the need for intubation should be reconsidered frequently,as pneumonia is predictive of NPPV failure.