Effects of positive end-expiratory pressure on tissue gas tensions and oxygen transport.
To determine whether positive end-expiratory pressure (PEEP) impairs peripheral tissue oxygenation, hemodynamic variables including blood and subcutaneous tissue gas tensions were measured at 0, 5, 10, 15, and 20 cm H2O of PEEP, in 9 patients who were being mechanically ventilated for acute pulmonary failure. Increasing the level of PEEP produced parallel decreases in cardiac output and oxygen delivery (DO2 = cardiac output X arterial oxygen content); however, there were no significant changes in mean arterial blood pressure (MAP), oxygen consumption (VO2), mixed-venous oxygen tension (PvO2), pH, or base excess. Subcutaneous tissue oxygen (PtO2) and carbon dioxide (PtCO2) tensions, which were directly measured in the femoral region by a mass spectrometer, also remained at their baseline levels (zero end-expiratory pressure). We concluded that peripheral tissue oxygenation is not impaired up to the level of 20 cm H2O of PEEP, even though DO2 significantly decreases.
D000208:Acute Disease; D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011175:Positive-Pressure Respiration; D012131:Respiratory Insufficiency / Q000097:blood / Q000378:metabolism / Q000628:therapy*
D002245:Carbon Dioxide; D010100:Oxygen