Coimbra Vera Regina de Morais, Lara Rodrigo de Almeida, Flores Eriko Gonçalves, Nozawa Emília, Auler José Octávio Costa, Feltrim Maria Ignez Zanetti
Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Arq Bras Cardiol. 2007 Nov;89(5):270-6, 298-305. doi: 10.1590/s0066-782x2007001700004.
To examine ventilatory response, oxygenation-related, and hemodynamics of patients with hypoxemic acute respiratory failure (ARF) submitted to noninvasive mechanical ventilation (NIV) during the postoperative phase of cardiovascular surgery in order to identify predictive variables of success, and to compare the different types of NIV.
Seventy patients with hypoxemic ARF were randomized to one of three modalities of NIV--continuous positive airway pressure (CPAP) and ventilation with two pressure levels (PEEP + SP and BiPAP). Ventilation, oxygenation-related, and hemodynamics variables were analyzed at pre-application, and 3, 6, and 12 hours after the protocol began.
Thirteen patients were excluded. Thirty-one patients progressed to independence from ventilatory support and comprised the success group, and 26 required orotracheal intubation and were considered the nonsuccess group. Age, initial heart rate (HR), and respiratory rate (RR) showed elevated levels in the nonsuccess group (p=0.042, 0.029, and 0.002, respectively). A greater number of intraoperative complications were seen in the nonsuccess group (p=0.025). Oxygenation variables increased only in the success group. Among the NIV types, 57.9% of patients in the ventilator group, 57.9% in the two-pressure levels group, and 47.3% in the CPAP group progressed with success. Oxygenation and RR variables showed improvement only in the groups with two pressure levels.
Patients with hypoxemic ARF in the postoperative stage after cardiovascular surgery showed better oxygenation, RR, and HR during NIV application. In older patients and those with higher baseline RR and HR values, NIV was not sufficient to reverse ARF. The two-pressure level modes showed better results.
研究低氧性急性呼吸衰竭（ARF）患者在心血管手术后接受无创机械通气（NIV）时的通气反应、氧合相关指标及血流动力学，以确定成功的预测变量，并比较不同类型的NIV。
70例低氧性ARF患者被随机分为三种NIV模式之一——持续气道正压通气（CPAP）以及两种压力水平的通气模式（PEEP + SP和双水平气道正压通气BiPAP）。在应用前以及方案开始后3、6和12小时分析通气、氧合相关及血流动力学变量。
13例患者被排除。31例患者成功脱离通气支持，组成成功组，26例患者需要气管插管，被视为非成功组。非成功组患者的年龄、初始心率（HR）和呼吸频率（RR）水平较高（分别为p = 0.042、0.029和0.002）。非成功组术中并发症更多（p = 0.025）。仅成功组的氧合变量增加。在NIV类型中，通气模式组57.9%的患者、双压力水平组57.9%的患者以及CPAP组47.3%的患者成功好转。仅双压力水平组的氧合和RR变量有所改善。
心血管手术后处于术后阶段的低氧性ARF患者在应用NIV期间氧合、RR和HR情况较好。对于老年患者以及基线RR和HR值较高的患者，NIV不足以逆转ARF。双压力水平模式显示出更好的效果。
