Titrating positive end-expiratory pressure therapy in patients with early, moderate arterial hypoxemia

A prospective randomized study to compare two physiologic end-points for titrating positive end-expiratory pressure (PEEP) was performed in patients with early, moderate arterial hypoxemia after surgery or trauma. All patients initially received 5 cm H2O of PEEP. In group 1 patients, PEEP was increased only if PaO2 decreased below 65 torr on an inspired oxygen fraction (FIO2) of 0.45. PEEP was then added in 2- to 3-cm H2O increments until PaO2 again was above 65 torr. Group 2 patients were treated with incremental PEEP until the PaO2/FIO2 ratio was greater than 300 or physiologic shunt (Qsp/Qt) was less than 0.20. All therapy other than PEEP was similar in the two groups. There were no statistically significant differences in entry PaO2 (mean 85 +/- 11 [SD] and 87 +/- 11 torr in groups 1 and 2, respectively), and Qsp/Qt was 0.22 in each group. Five (28%) of 18 patients in group 1 and 19 (95%) of 20 patients in group 2 received more than 5 cm H2O of PEEP. Between groups 1 and 2 there were no statistically significant differences in days intubated (3.4 +/- 3 vs. 5.3 +/- 5, respectively), ICU days (5.3 +/- 3 vs. 6.6 +/- 5), hospitalization days (26 +/- 24 vs. 28 +/- 24), incidence of pulmonary barotrauma (0/18 vs. 1/20), ICU mortality (22% vs. 20%), or overall mortality (33% vs. 25%). The number of blood gas analyses and cardiac output measurements, and the total hospital charges were also similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)