Interdepartmental Division of Critical Care, University of Toronto, Toronto, Canada.
Intensive Care Med. 2010 Apr;36(4):585-99. doi: 10.1007/s00134-009-1748-1. Epub 2010 Feb 4.
Prone position ventilation for acute hypoxemic respiratory failure (AHRF) improves oxygenation but not survival, except possibly when AHRF is severe.
To determine effects of prone versus supine ventilation in AHRF and severe hypoxemia [partial pressure of arterial oxygen (PaO(2))/inspired fraction of oxygen (FiO(2)) <100 mmHg] compared with moderate hypoxemia (100 mmHg < or = PaO(2)/FiO(2) < or = 300 mmHg).
Systematic review and meta-analysis.
Electronic databases (to November 2009) and conference proceedings.
Two authors independently selected and extracted data from parallel-group randomized controlled trials comparing prone with supine ventilation in mechanically ventilated adults or children with AHRF. Trialists provided subgroup data. The primary outcome was hospital mortality in patients with AHRF and PaO(2)/FiO(2) <100 mmHg. Meta-analyses used study-level random-effects models.
Ten trials (N = 1,867 patients) met inclusion criteria; most patients had acute lung injury. Methodological quality was relatively high. Prone ventilation reduced mortality in patients with PaO(2)/FiO(2) <100 mmHg [risk ratio (RR) 0.84, 95% confidence interval (CI) 0.74-0.96; p = 0.01; seven trials, N = 555] but not in patients with PaO(2)/FiO(2) > or =100 mmHg (RR 1.07, 95% CI 0.93-1.22; p = 0.36; seven trials, N = 1,169). Risk ratios differed significantly between subgroups (interaction p = 0.012). Post hoc analysis demonstrated statistically significant improved mortality in the more hypoxemic subgroup and significant differences between subgroups using a range of PaO(2)/FiO(2) thresholds up to approximately 140 mmHg. Prone ventilation improved oxygenation by 27-39% over the first 3 days of therapy but increased the risks of pressure ulcers (RR 1.29, 95% CI 1.16-1.44), endotracheal tube obstruction (RR 1.58, 95% CI 1.24-2.01), and chest tube dislodgement (RR 3.14, 95% CI 1.02-9.69). There was no statistical between-trial heterogeneity for most clinical outcomes.
Prone ventilation reduces mortality in patients with severe hypoxemia. Given associated risks, this approach should not be routine in all patients with AHRF, but may be considered for severely hypoxemic patients.
俯卧位通气可改善急性低氧性呼吸衰竭（AHRF）患者的氧合作用，但不能改善存活率，除非 AHRF 非常严重。
确定俯卧位与仰卧位通气在 AHRF 及严重低氧血症[动脉血氧分压（PaO2）/吸入氧分数（FiO2）<100mmHg]中的作用，与中度低氧血症（100mmHg≤PaO2/FiO2≤300mmHg）相比。
系统评价和荟萃分析。
电子数据库（截至 2009 年 11 月）和会议记录。
两位作者独立选择并从机械通气的成人或儿童 AHRF 患者的俯卧位与仰卧位通气的平行组随机对照试验中提取数据。试验人员提供了亚组数据。主要结局为 AHRF 患者且 PaO2/FiO2<100mmHg 时的住院死亡率。荟萃分析使用了研究水平的随机效应模型。
10 项试验（N=1867 例患者）符合纳入标准；大多数患者患有急性肺损伤。方法学质量相对较高。俯卧位通气降低了 PaO2/FiO2<100mmHg 的患者的死亡率[风险比（RR）0.84，95%置信区间（CI）0.74-0.96；p=0.01；7 项试验，N=555]，但对 PaO2/FiO2≥100mmHg 的患者无影响（RR 1.07，95%CI 0.93-1.22；p=0.36；7 项试验，N=1169）。亚组间风险比差异显著（交互作用 p=0.012）。事后分析表明，在更严重低氧血症的亚组中，死亡率显著改善，并且在使用一系列 PaO2/FiO2 阈值直至约 140mmHg 时，亚组间存在显著差异。俯卧位通气在治疗的头 3 天内将氧合作用提高了 27%-39%，但增加了压疮（RR 1.29，95%CI 1.16-1.44）、气管内管阻塞（RR 1.58，95%CI 1.24-2.01）和胸腔引流管移位（RR 3.14，95%CI 1.02-9.69）的风险。大多数临床结局的试验间无统计学异质性。
俯卧位通气可降低严重低氧血症患者的死亡率。鉴于相关风险，这种方法不应在所有 AHRF 患者中常规应用，但可考虑用于严重低氧血症患者。
