自主呼吸试验在撤离呼吸机中的作用

The effect of spontaneous breathing trial on weaning from ventilators

目的探讨自主呼吸试验（SBT）在机械通气的撤离、拔除气管插管过程中的作用。方法采用前瞻性随机对照方法，选择67例机械通气超过48h的患者，当所有患者达到撤离呼吸机状态时将其随机（采用从密封信封中抽取随机号的方法）分为自主呼吸试验组（SBT组，35例）和无自主呼吸试验组（NO-SBT组，32例）两组。SBT组患者顺利通过SBT后随即拔除气管插管，NO—SBT组患者在达到撤离呼吸机条件后，不进行SBT，即拔除气管插管。以拔除气管插管的成功率作为评判的主要指标，成功的标志为拔除气管插管后能维持自主呼吸48h以上。两组均数的比较采用两个独立样本的t检验，频数的比较采用χ2检验。结果两组患者在拔除气管插管前的一般状况、呼吸生理和血流动力学等指标比较差异无统计学意义；年龄、性别、气管插管的口径、疾病的严重程度和疾病种类相似，机械通气的时间比较差异无统计学意义。两组各有3例患者再次气管插管（χ2=0．013，P=0．908）。两组患者拔除气管插管后，需无创辅助通气的患者NO—SBT组为5例，SBT组为4例（χ2=0．253，P=0．727）。两组患者医院内病死率[NO—SBT组为12．5％（4／32），SBT组为9．7％（3／35）,χ2=0．311，P=0．600]差异无统计学意义。结论SBT可能不是拔除气管插管前的必需过程。

Objective To investigate whether spontaneous breathing trial is an essential process during weaning from ventilator in critically cared patients without chronic obstructive pulmonary disease （COPD）. Methods The study was performed with a prospective, randomized, double-blinded method. A total of 67 adult patients, mechanically ventilated for at least 48 h in SICU of a teaching hospital, were enrolled. As soon as the patients were ready for weaning from ventilators, they were randomly assigned to 2 groups with target extubation without spontaneous breathing trial （SBT） （non-SBT group） and with SBT （SBT group）. In the SBT group, the patient who tolerated the spontaneous breathing trial underwent immediate extubation. In the non-SBT group, as soon as a patient met weaning readiness criteria, he or she underwent extubation without SBT process. The primary outcome measure was successful extubation, defined as the ability to maintain spontaneous breathing for 48 hrs after extubation. Results were expressed as mean ± SD. Mean values between the 2 groups were compared by student＇ s t tests. The differences in proportions between the 2 groups were determined using χ2-test. Results There were no significant differences in demographic, respiratory, and hemodynamic characteristics between the 2 groups at the end of assessing weaning readiness criteria. Three （9.7%） patients in the SBT group and 3 （9.4%） patients in the non- SBT group needed reintubation （ χ2 =0.013, P=0. 908）. Five patients in the non-SBT group and 4 in the SBT group required noninvasive ventilation following extubation （χ2=0. 253, P = 0. 727 ）. There were no significant differences in in-hospital mortality between the 2 groups （ χ2 = 0. 276, P = 0. 600）. Conclusion The result suggests that spontaneous breathing trial may be not a necessary procedure preceding extubation in a general intensive care population.