Comparison of Two Protective Mechanical Ventilation Strategies After Cardiac Surgery: Aggressive Versus Moderate Alveolar Recruitment Strategies
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 320
- 试验地点
- 1
- 主要终点
- Severity of Pulmonary Complications in the Post-operative Period
研究概览
简要总结
The purpose of this study was to evaluate prospectively the impact of two protective mechanical ventilation strategies, both using low tidal volume ventilation (6 mL/kg/ibw) after cardiac surgery. The study selected patients presenting signals of deficient gas exchange (PaO2/FIO2 < 250 at a PEEP [positive end expiratory pressure] of 5 cmH2O) in the immediate post-operative period. An aggressive alveolar recruitment protocol applying opening pressures of 45 cmH2O, followed by ventilation with PEEP = 13 cmH2O, was compared to the standard alveolar recruitment protocol of the institution, where an opening pressure of 20 cmH2O in the airways is followed by ventilation with PEEP = 8 cmH2O. After a stabilizing period of four hours of controlled mechanical ventilation, the patients followed the routine weaning protocol and physiotherapy protocol of the institution.
详细描述
The postoperative period of cardiac surgery is associated with the development of pulmonary complications. Functional residual capacity can be reduced up to 50% and pulmonary volumes may be decreased until three months after surgery.
Lung injury is the result of pulmonary inflammation (activated by cardiopulmonary bypass, the surgical procedure itself and ischemia-reperfusion injury), the adopted mechanical ventilation strategy and a consequence of previous cardiac and/or pulmonary dysfunction.
The use of protective mechanical ventilation strategies with low tidal volumes since the immediate postoperative period, or since the operating room, has been shown to attenuate and prevent lung injury in previous studies selecting with high-risk patients.
A more complex topic, however, has been the proof of the additional benefit of alveolar recruitment maneuvers during the brief period of mechanical ventilation after surgery. While the experimental evidence suggests that the use of an open lung approach could minimize the shearing forces in the lung parenchyma, enhancing the protection afforded by low tidal volume ventilation, innumerous concerns about the hemodynamic side effects, and the possibility of barotrauma have prevented the routine use of intensive alveolar recruitment protocols. Another matter of concern is the net efficacy of a recruitment maneuver applied in the post-operative period, instead of the intra-operative period.
Thus, this study compared the impact of two protective mechanical ventilation strategies, both using low-tidal volume ventilation (6 mL/kg/ibw) after cardiac surgery, in a selective population of patients presenting signals of deficient gas exchange (PaO2/FIO2 < 250 at a PEEP of 5 cmH2O) in the immediate post-operative period. In a previous study at this institution, this subgroup of patients was shown to be at higher risks of postoperative pulmonary complications.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Triple (Participant, Care Provider, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Immediate postoperative period of myocardial revascularization and/or heart valve surgery (aortic and/or mitral)
- •Age > 18 years and < 80 years
- •No previous pulmonary disease
- •Left ventricular ejection fraction > 35%
- •Body mass index < 40 kg/m2
- •Oxygen index (PaO2/FiO2) < 250
- •Corrected volemic status (negative raising legs mean arterial pressure [MAP] variation < 10%)
- •Written inform consent
排除标准
- •MAP (mean arterial pressure) < 60 mmHg
- •Noradrenaline > 2 micrograms/Kg/min
- •Acute arrhythmias
- •Blooding associated to hemodynamic instability
- •Need of re-surgery and/or mechanical circulatory assistance
- •Suspicion of neurological alteration
- •Chest tube with persistent air leak
结局指标
主要结局
Severity of Pulmonary Complications in the Post-operative Period
时间窗: Participants were followed for the duration of hospital stay.
Score of pulmonary complications adapted from previous publications, with 5 degrees, where the higher one means death before hospital discharge, degree (4) means the need of mechanical ventilation for more than 48 hours after surgery or after reintubation, degree (3) means pneumonia or intense noninvasive ventilation need, degree (2) means hypoxemia and abnormal lung findings, degree 1 means simple atelectasis and degree (0) means no complication. The comparison used this ordinal variable, representing the highest score achieved during the post-operative period. The comparison between arms was made through the Mann-Whitney U test. Data shown are percentage of participants with pulmonary complications grade ≥ 3.
次要结局
- Incidence of Barotrauma(Five days after surgery)
- Length of ICU Stay(From the day of surgery up to ICU discharge, maximum censoring at day 28 after surgery)
- Length of Hospital Stay(From the day of surgery up to Hospital discharge, maximum censoring at day 28 after surgery)
- Hospital Mortality(From the day of surgery up to Hospital discharge or death, with no maximum censoring.)
研究者
Alcino Costa Leme
Supervisor of respiratory post-operative care - Incor Heart Institute
University of Sao Paulo