POSITIVE END-EXPIRATORY PRESSURE DURING ONE-LUNG VENTILATION IMPROVESOXYGENATION IN PATIENTS WITH LOW ARTERIAL OXYGEN-TENSIONS

Objective: The application of 10 cm H2O of positive end-expiratory pre ssure (PEEP(10)) to the ventilated lung during one-lung ventilation (O LV) has an unpredictable effect on PaO2. It was hypothesized that pati ents with a low PaO2 (<80 mmHg) during OLV may benefit from applicatio n of PEEP. Design: Prospective, open. Setting: A university medical ce nter. Participants: Eighteen patients were studied who were undergoing OLV for pulmonary resection. All were anesthetized with thiamylal, N2 O/O-2 (50%/50%), isoflurane, and pancuronium. Interventions: Applicati on of PEEP(10) during one-lung ventilation. Measurements and Main Resu lts: Hemodynamics and oxygenation were measured during two-lung ventil ation in the lateral position, OLV, and OLV plus application of PEEP(1 0). Overall, PEEP(10) during OLV failed to produce significant changes in PaO2, Qs/Qt%, cardiac output (CO), SvO(2), or mean arterial pressu re. However, in 11 patients whose PaO2 was less than 80 mmHg during OL V, application of PEEP(10) significantly increased PaO2, decreased Qs/ Qt%, and decreased CO (p < 0.05). In the 7 patients whose PaO2 was gre ater than 80 mmHg on OLV, the authors did not find a significant effec t of PEEP(10) on the hemodynamic or oxygenation parameters measured. C onclusions: In patients with a low PaO2 (<80 mmHg) during OLV with F1O 2 = 0.5, PaO2 is increased by the application of PEEP(10). This maneuv er may be useful in situations in which application of continuous posi tive airway pressure (CPAP) to the nonventilated lung is not possible. Copyright (C) 1996 ny W.B. Saunders Company