Beneficial effect of a prone position for patients with hypoxemia after transthoracic esophagectomy

OBJECTIVE: Although the prone position has been reported to improve arterial oxygenation in patients with acute respiratory distress syndrome, there have been no reports on its efficacy in patients with hypoxemia after transthoracic esophagectomy with three-field lymphadenectomy. This study was undertaken to assess the efficacy of the prone position on hypoxemia after three-field lymphadenectomy for thoracic esophageal carcinoma. DESIGN: Prospective randomized clinical study. SETTING: General intensive care unit at a university hospital. INTERVENTIONS AND MEASUREMENTS: Sixteen patients who underwent three-field lymphadenectomy and showed hypoxemia (PaO2/FiO2 ratios of <200 under positive end-expiratory pressure of >5 cm H2O) on the fifth postoperative day were randomly assigned to prone (eight patients) and nonprone (eight patients) groups. Prone position for 6 hrs was carried out for four consecutive days. The PaO2/FiO2 ratio, the duration of ventilatory support, and length of stay, were measured. RESULTS: Oxygenation: The PaO2/FiO2 ratio markedly increased by 32% +/- 22% in seven of eight patients (p <.05) when the patients were moved from the supine to the prone position. The PaO2/FiO2 ratio after the fourth prone position (238 +/- 55, p <.05) was significantly higher than that before the first trial of prone position (166 +/- 25) in these seven patients. Duration of ventilatory support and intensive care unit length of stay: Both the ventilation period (11.6 +/- 2.2 vs. 14.0 +/- 1.6 days, p =.0029) and the length of stay in the intensive care unit (12.8 +/- 4.4 vs. 17.2 +/- 3.4 days, p =.0032) were significantly shorter in the prone group compared with the nonprone group. The PaO2/FiO2 ratio at the time of cessation of prone positioning was significantly higher than the corresponding value in the nonprone group. CONCLUSION: In hypoxemic patients after three-field lymphadenectomy, the prone position improved arterial oxygenation without any deleterious effects. The beneficial effect of the prone position is possibly attributable to opening of the bronchi obstructed by secretions.