Effects of PEEP on pulmonary hemodynamics in intact dogs with oleic acid pulmonary edema.
The effects of positive end-expiratory pressure (PEEP) on the pulmonary circulation were studied in 14 intact anesthetized dogs with oleic acid (OA) lung injury. Transmural (tm) mean pulmonary arterial pressure (Ppa)/cardiac index (Q) plots with transmural left atrial pressure (Pla) kept constant were constructed in seven dogs, and Ppa(tm)/PEEP plots with Q and Pla(tm) kept constant were constructed in seven other dogs. Q was manipulated by using a femoral arteriovenous bypass and a balloon catheter inserted in the inferior vena cava. Pla was manipulated using a balloon catheter placed by thoracotomy in the left atrium. Ppa(tm)/Q plots were essentially linear. Before OA, the linearly extrapolated pressure intercept of the Ppa(tm)/Q relationship approximated Pla(tm). OA (0.09 ml/kg into the right atrium) produced a parallel shift of the Ppa(tm)/Q relationship to higher pressures; i.e., the extrapolated pressure intercept increased while the slope was not modified. After OA, 4 Torr PEEP (5.4 cmH2O) had no effect on the Ppa(tm)/Q relationship and 10 Torr PEEP (13.6 cmH2O) produced a slight, not significant, upward shift of this relationship. Changing PEEP from 0 to 12 Torr (16.3 cmH2O) at constant Q before OA led to an almost linear increase of Ppa(tm) from 14 +/- 1 to 19 +/- 1 mmHg. After OA, Ppa(tm) increased at 0 Torr PEEP but changing PEEP from 0 to 12 Torr did not significantly affect Ppa(tm), which increased from 19 +/- 1 to 20 +/- 1 mmHg. These data suggest that moderate levels of PEEP minimally aggravate the pulmonary hypertension secondary to OA lung injury.
Leeman
M
M
Laboratory of Cardiovascular and Respiratory Physiology, Erasme University Hospital, Brussels, Belgium.
Lejeune
P
P
Closset
J
J
Vachiéry
J L
JL
Mélot
C
C
Naeije
R
R
D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D004285:Dogs; D006339:Heart Rate; D006439:Hemodynamics; D019301:Oleic Acid; D009829:Oleic Acids; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010313:Partial Pressure; D011175:Positive-Pressure Respiration; D011652:Pulmonary Circulation; D011654:Pulmonary Edema / Q000139:chemically induced / Q000503:physiopathology*
D009829:Oleic Acids; D002245:Carbon Dioxide; D019301:Oleic Acid; D010100:Oxygen