机械通气压力控制通气-辅助/控制模式下吸呼切换时机不当所致人机对抗情况及处理措施

摘要

目的 分析机械通气压力控制通气-辅助/控制(PCV-A/C)模式下吸呼切换时机不当所致人机对抗情况及处理措施.方法 选取2016年6月—2017年4月中国人民解放军总医院呼吸重症监护室(RICU)收治的肺部感染所致呼吸衰竭患者19例,均经鼻或口行气管插管机械通气治疗并发生人机对抗.PCV-A/C模式下,P-T曲线表现为吸气末"超射波",考虑切换延迟,适当缩短吸气时间使波形呈现方波;P-T曲线表现为吸气末"双吸气波",考虑切换过早或压力不足,延长呼气时间或增加压力使波形呈现方波.比较人机对抗时和消除人机对抗后潮气量(VT)、呼吸频率(f)、平均动脉压(MAP)、心率(HR)、浅快呼吸指数(RSBI);随访28 d,观察患者预后.结果 19例患者中出现"超射波"10例,占52.6%;出现"双吸气波"9例,占47.4%.消除人机对抗后VT大于人机对抗时, f、MAP、HR及RSBI低于人机对抗时(P<0.05).随访28 d,19例患者中死亡12例,余7例成功拔除气管插管.结论 PCV-A/C模式下吸呼切换时机不当所致人机对抗表现为"超射波"和"双吸气波",患者预后较差,消除人机对抗后患者呼吸、血压、心率得到有效改善.%Objective To analyze the features of patient-ventilator asynchrony caused by improper respiratory switching of pressure control ventilation-A/C mode and treatment measures. Methods From June 2016 to April 2017, a total of 19 patients with pulmonary infection-induced respiratory failure were selected in the Respiratory Intensive Care Unit, General Hospital of the Chinese People′s Liberation Army, all of them received pernasal or peroral endotracheal intubation and mechanical ventilation, and all of them occurred patient-ventilator asynchrony. Under pressure control ventilation-A/C mode, P-T curve showed end-inspiratory "vershoot wave" may due to delayed respiratory switching, that should shorten the inspiratory time to make the waveform transform to square wave; P-T curve showed end-inspiratory "double inspiratory wave" may due to untimely respiratory switching or pressure shortage, that should lengthen the expiratory time or increase the pressure to make the waveform transform to square wave. Tidal volume (VT), respiratory rate (f), mean arterial pressure (MAP), heart rate (HR) and rapid shallow breathing index (RSBI) during and after adjustment of patient-ventilator asynchrony were compared, and the prognosis was observed after 28-day follow-up. Results Of the 19 patients, 10 patients occurred "overshoot wave" (accounting for 52.6%), the other 9 patients occurred "double inspiratory wave" (accounting for 47.4%). After adjustment of patient-ventilator asynchrony, VT was statistically significantly larger that that during patient-ventilator asynchrony, while f, MAP, HR and RSBI were statistically significantly lower than those during patient-ventilator asynchrony (P<0.05). After 28-day follow-up, 12 patients died, the other 7 patients successfully removed the endotracheal intubation. Conclusion Patient-ventilator asynchrony caused by improper respiratory switching of pressure control ventilation-A/C mode mainly performed as "overshoot wave" and "double inspiratory wave", which may result in poor prognosis, adjustment of patient-ventilator asynchrony can effectively adjust regulate the respiration, blood pressure and HR.