对无创正压通气治疗SARS时机的思考

Timing of Noninvasive Positive Pressure Ventilation for Patients with Severe Acute Respiratory Syndrome

将25例严重急性呼吸综合征(SARS)合并呼吸功能不全而使用无创正压通气(NIPPV)治疗的病人分为2组生存组和死亡组。比较2组病人在NIPPV前与治疗后24h急性生理与慢性健康状况Ⅱ(APACHEⅡ)评分、呼吸频率(RR)、脉搏血氧饱和度(SpO2)、改良呼吸指数(PO2/FiO2,MRI)的变化,以探讨NIPPV治疗SARS的时机与作用。结果死亡组病人从发病到NIPPV治疗的平均时间明显晚于生存组病人,虽然NIPPV能改善2组病人的氧合状态,但经过NIPPV24h后,死亡组的APACHEⅡ、RR仍显著高于生存组(P<0.05),且死亡组的SpO2、MRI明显低于生存组(P<0.05)。提示NIPPV治疗时机对危重病人的生存可能至关重要。当病人呼吸频率逐渐加快且血氧饱和度及氧合指数出现较快下降趋势时,应综合考虑病人整体生理状况,适当放宽上机适应证,尽早进行NIPPV治疗。

The objective was to compare the collectable relevant physiological data of survivors and non-survivors of severe acute respiratory syndrome(SARS)on noninvasive positive pressure ventilation(NIPPV),and to evaluate the timing of NIPPV for SARS.Methods:Twenty-five SARS patients with respiratory dysfunction on NIPPV were divided into two groups:survivor group(n=13)and non-survivor group(n=12).The PAPCHEⅡscore,respiratory rate(RR),saturation of oxygen(SpO 2 )and modificative repiratory index(MRI)were compared between the survivors and non-survivors before NIPPV and after NIPPV for three to twenty four hours,respectively.Results:NIPPV administered with full-face masks avoided the need for endotracheal intubation,with rapidly improved vital signs and gas exchange and sense of dyspnea.Although NIPPV could be one of the effective treatments for improving oxygenation in both groups during the initial3to24h of ventilatory support,the patients in non-survivor group had higher PAPCHEⅡscore,respiratory rates and lower SpO 2 ,MRI than those of the patients in survivor group(P<0.05)at the same intervals.The average time span from beginning of SARS to NIPPV in the non-survivor group was much longer than that in survivor group.Four patients in non-survivor group and none in survivor group were intubated at last.The non-survivors underlying diseases were easily accompanied with serious nosocomial pneumonia and multiple organ dysfunction syndrome(MODS).conclusions:Because severe SARS might rapidly deteriorate,appropriate use of NIPPV should be recommended,and NIPPV or IPPV should be given without hesitation when refractory hypoxemia is found.Noninvasive ventilation should be used as a preventive tool against endotracheal intubation rather than as an alternative treatment for acute respiratory failure related to SARS.Therefore,efforts should be made to avoid missing the timing for intubation.Because gas exchange disturbances in advanced SRAS may not be amenable to NIPPV,available indications for NIPPV should not be restricted.Several factors are vital to the success of NIPPV therapy,including training and experience of the staff,appropriate patient selection,properly timed intervention,patient coaching and encouragement and careful monitoring.Because most relevant studies have been retrospective and uncontrolled,many issues remain unresolved.The safety and efficacy of NIPPV,the most appropriate selection of patients and timing of intervention for SARS need to be further studied.