Nakos G, Tsangaris I, Kostanti E, Nathanail C, Lachana A, Koulouras V, Kastani D
Intensive Care Unit, University Hospital of Ioannina, Ioannina,
Am J Respir Crit Care Med. 2000 Feb;161(2 Pt 1):360-8. doi: 10.1164/ajrccm.161.2.9810037.
This study examined the effect of the prone position on mechanically ventilated patients with hydrostatic pulmonary edema (HPE). Eight patients with acute HPE and mechanically ventilated in the prone position (Group 1) were studied. Six patients with acute HPE and mechanically ventilated in the supine position (Group 2), 20 patients with ARDS (Group 3), and 5 patients with pulmonary fibrosis (PF) (Group 4) served as control patients. Patients with HPE, who after being mechanically ventilated for at least 6 h needed an FI(O(2)) >/= 0.6 to achieve an Sa(O(2)) of approximately 90%, and did not respond to recruitment maneuvers, were turned to the prone position. Parameters of oxygenation, lung mechanics, and hemodynamics were determined in both the supine and prone positions. All patients with HPE exhibited improvement of oxygenation when they were placed in the prone position. The Pa(O(2))/FI(O(2)) ratio increased from 72 +/- 16 in the supine position to 208 +/- 61 after 6 h in the prone position (p < 0.001); the rise in Pa(O(2)) was persistent, without detrimental effect on hemodynamics. Fifteen of 20 patients with ARDS (75%) improved oxygenation when in the prone position. The Pa(O(2))/FI(O(2)) ratio increased from 83 +/- 14 in the supine position to 189 +/- 34 after 6 h in the prone position (p < 0.001). In contrast, 5 of 20 patients with ARDS (25%) and none of the patients with PF responded favorably to prone positioning. Patients with HPE and early ARDS responded better to prone positioning than did patients with late ARDS and PF. Patients with HPE and ventilated in the supine position had a lower Pa(O(2))/FI(O(2)) ratio and the duration of mechanical ventilation was longer compared with that of patients in the prone position. Our results show that the prone position may be a useful maneuver in treating patients with severe hypoxemia due to pulmonary edema. The presence of pulmonary edema, as in early ARDS and HPE predicts a beneficial effect of the prone position on gas exchange. In contrast, the presence of fibrosis, as in late ARDS and pulmonary fibrosis, predisposes to nonresponsiveness to prone positioning.
本研究探讨了俯卧位对机械通气的静水压性肺水肿（HPE）患者的影响。研究了8例急性HPE且采用俯卧位机械通气的患者（第1组）。6例急性HPE且采用仰卧位机械通气的患者（第2组）、20例急性呼吸窘迫综合征（ARDS）患者（第3组）和5例肺纤维化（PF）患者（第4组）作为对照患者。HPE患者在机械通气至少6小时后，若需要吸入氧分数（FI(O₂)）≥0.6才能使动脉血氧饱和度（Sa(O₂)）达到约90%，且对肺复张手法无反应，则转为俯卧位。分别在仰卧位和俯卧位测定氧合、肺力学和血流动力学参数。所有HPE患者在转为俯卧位后氧合均有改善。动脉血氧分压（Pa(O₂)）/吸入氧分数（FI(O₂)）比值从仰卧位时的72±16升高至俯卧位6小时后的208±61（p<0.001）；Pa(O₂)的升高持续存在，且对血流动力学无不利影响。20例ARDS患者中有15例（75%）在俯卧位时氧合改善。Pa(O₂)/FI(O₂)比值从仰卧位时的83±14升高至俯卧位6小时后的189±34（p<0.001）。相比之下，20例ARDS患者中有5例（25%），且PF患者中无一例对俯卧位有良好反应。HPE和早期ARDS患者对俯卧位的反应优于晚期ARDS和PF患者。与俯卧位患者相比，仰卧位机械通气的HPE患者Pa(O₂)/FI(O₂)比值更低，机械通气时间更长。我们的结果表明，俯卧位可能是治疗因肺水肿导致严重低氧血症患者的一种有效方法。如早期ARDS和HPE中存在的肺水肿预示俯卧位对气体交换有有益作用。相比之下，如晚期ARDS和肺纤维化中存在的纤维化则易导致对俯卧位无反应。
