Easby Jason, Abraham Babu K, Bonner Stephen M, Graham Stephen
Critical Care Service, The James Cook University Hospital, Middlesbrough, TS4 3BW, UK.
Intensive Care Med. 2003 Dec;29(12):2303-2306. doi: 10.1007/s00134-003-1983-9. Epub 2003 Aug 28.
Pulmonary aspiration is a significant cause of admission to the ITU and is associated with significant morbidity and mortality. Aspiration in the supine position produces posterior collapse/consolidation, similar to that seen in ALI/ARDS patients. Prone positioning has been shown to improve oxygenation in ALI/ARDS, but no studies have been performed on pulmonary aspiration.
A prospective crossover study.
Twelve-bed ITU.
Eleven patients admitted to ITU with respiratory failure secondary to witnessed pulmonary aspiration requiring ventilation and an FIO(2) >0.50 after 12 h.
Patients were placed in a prone position for 8 h and then turned supine for 8 h. Prone positioning was repeated if the FIO(2) remained >0.50. Ventilator settings were not altered in the study period.
Arterial blood gas analysis was performed every 2 h. The PaO(2)/FIO(2) gradient was calculated. Oxygenation improved on turning prone, with a significant increase in the PaO(2)/FIO(2) ratio ( P<0.01). There was a fall in this gradient on return to the supine position. There was a significant improvement in oxygenation on turning prone for the second period ( P<0.01). Overall, there was a significant improvement in the PaO(2)/FIO(2) ratio in the final supine position when compared to the first ( P<0.05).
This study demonstrates a significant improvement in oxygenation in the prone position in pulmonary aspiration. Early prone positioning in patients with pulmonary aspiration requiring ventilation may improve oxygenation by altering V/Q relationships similarly to ARDS, but also may aid drainage of secretions, opening up alveoli and preventing progression to established pneumonitis.
肺误吸是入住重症监护病房（ITU）的一个重要原因，且与显著的发病率和死亡率相关。仰卧位误吸会导致肺后部萎陷/实变，类似于急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）患者的表现。俯卧位已被证明可改善ALI/ARDS患者的氧合，但尚未有关于肺误吸的相关研究。
一项前瞻性交叉研究。
拥有12张床位的ITU。
11名因目睹肺误吸继发呼吸衰竭而入住ITU的患者，这些患者需要机械通气，且在12小时后吸入氧分数（FIO₂）>0.50。
患者先俯卧8小时，然后仰卧8小时。如果FIO₂仍>0.50，则重复俯卧位。研究期间呼吸机设置不变。
每2小时进行一次动脉血气分析，并计算动脉血氧分压（PaO₂）/FIO₂梯度。转为俯卧位时氧合改善，PaO₂/FIO₂比值显著增加（P<0.01）。恢复仰卧位时该梯度下降。第二次转为俯卧位时氧合有显著改善（P<0.01）。总体而言，与第一次仰卧位相比，最终仰卧位时的PaO₂/FIO₂比值有显著改善（P<0.05）。
本研究表明俯卧位可显著改善肺误吸患者的氧合。对于需要机械通气的肺误吸患者，早期采用俯卧位可能通过类似ARDS的方式改变通气/血流比值来改善氧合，还可能有助于分泌物引流、开放肺泡并防止发展为确诊的肺炎。
