Recruitment maneuver and high positive end-expiratory pressure improve hypoxemia in patients after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism*

Abstract

To investigate the effects of a recruitment maneuver and high positive end-expiratory pressure (PEEP) on oxygenation and hemodynamics in hypoxemic patients with pulmonary hypertension after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism. Prospective, observational, clinical study. A surgical intensive care unit in a national heart institute. Fourteen consecutively admitted patients who developed acute lung injury (Pa(O2) <300 torr at F(IO2) 1.0) and pulmonary hypertension (mean pulmonary artery pressure >25 mm Hg) after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism. The recruitment maneuver was an increase of PEEP to 30 cm H2O in one step for 1 min at F(IO2) 1.0. The level of pressure control ventilation during the recruitment maneuver was the same as before the maneuver. Subsequently, PEEP was decreased in 15-min intervals from 15 to 10, 5, and 0 cm H2O. Hemodynamics and respiratory variables were analyzed before and during the recruitment maneuver and at each PEEP level. At F(IO2) 1.0, Pa(O2) increased from 240 +/- 62 torr to 470 +/- 83 torr at 15 cm H2O of PEEP and 469 +/- 75 torr at 10 cm H2O of PEEP after the recruitment maneuver (p < .001). At 15 cm H2O of PEEP, cardiac index decreased (from 2.7 +/- 0.6 at baseline to 2.2 +/- 0.3 L.min(-1).m(-2), p < .01) and mean blood pressure decreased (from 86 +/- 8 at baseline to 74 +/- 11 mm Hg, p < .05), but they returned to the baseline levels at 10 cm H2O of PEEP (2.5 +/- 0.4 L.min(-1).m(-2) and 83 +/- 9 mm Hg). There were no differences in mean pulmonary artery pressure at different levels of PEEP. In hypoxemic patients with pulmonary hypertension after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism, oxygenation was improved by the recruitment maneuver followed by high PEEP. However, hemodynamics were transiently suppressed and overall oxygen delivery did not change.