比例辅助通气、压力支持通气、间歇正压通气对急性呼吸衰竭患者心肺功能影响的比较

目的 观察比例辅助通气（PAV）在临床初步应用疗效及其对急性呼吸衰竭患者呼吸、循环功能的影响，并与间歇正压通气（IPPV）、压力支持通气（PSV）进行比较，为PAV临床广泛应用奠定基础。方法 对10例急性呼衰患者先用IPPV模式通气，同时计算弹性阻力（Ers)和粘性阻力（Rrs)，然后将模式改为PSV，根据IPPV时数据设置支持压力，使得潮气量（VT）与IPPV时大致相同。再将模式改为PAV，根据PSV时的数据设置辅助百分比，使得VT和峰压（Ppeak)分别与PSV时大致相同。观察通气期间呼吸力学、血气和血流动力学的变化。结果 在VT相似的情况下，PAV时Ppeak显著低于PSV、IPPV，其患者呼吸功（WOBp)、呼吸机呼吸功（WOBv)均低于PSV、IPPV、PAV与PSV相比，血流动力学各参数间无显著差异，PAV与IPPV相比，其中心静脉压（CVP）和肺毛细血管楔压比，血流动力学各参数间无显著差异，PAV与IPPV相比，其中心静脉压（CVP）和肺毛细血管楔压（PCWP）显著低于IPPV。PAV与PSV相比，在Ppeak相似的情况下，PAV时VT、平均动脉压（mBP)、心输出量（CO）高于PSV，其平均肺动脉压（mPAP)、WOBp低于PSV，其中WOBp显著低于PSV。结论 对于临床急性呼衰患者，PAV与PSV、IPPV相比，其气道压力低，减少了呼吸功，对血流动力学影响较小。

A comparison of the effects of PAV, PSV and IPPV on cardiopulmonary function in patients with acute respiratory failure

Objective Comparing the effects of proportional assist ventilation (PAV), pressure support ventilation (PSV), and intermittent positive pressure ventilation (IPPV) on cardiopulmonary function in patients with acute respiratory failure, in particular, evaluating the clinical significance of PAV. Methods Ten patients with acute respiratory failure were firstly ventilated with IPPV. Elaslance (Ers) and Resistance (Rrs) were measured and calculated. Then PSV mode was adapted. Based on the parameters of IPPV, inspiratory positive airway pressure was adjusted to maintain the same tidal volume (V T) as that in IPPV. Finally PAV mode was used. According to the parameters of PSV, the assist ratio was adjusted to maintain the same V T and peak pressurel Ppeak, as those in PSV. Respiratory mechamics, arterial blood gas and hemodynamics were recorded during above three modes of ventilation. Result Comparing with PSV and IPPV mode, PAV created a significantly lower Ppeak, less work of breathing of patients (WoBp) and work of breathing of ventilation (WoBv) under the similar V T; Central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) were significantly lower in PAV mode as compared with those in IPPV; While comparing with PSV, V T, mean blood pressure (mBP) and cardiac output (CO) were higher and mean pulmonary arterial pressure (mPAP), WoBp were lower in patients with PAV under similar Ppeak. Among them the fall of WoBp was statistically significant. Conclusion In patients receiving three modes of ventilation, PAV presents with lower airway pressure, less WoBp and less effect on hemodynamics as compared with those with PSV or IPPV.