Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease.
OBJECTIVE
To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe.


METHODS
Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi, st) was measured when PEEPe was zero, and the PEEPi, st was called PEEPi, stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi, stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed.


RESULTS
When PEEPe was not higher than 80% of PEEPi, stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi, stz, PEEPi, st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P < 0.01. Cardiac output and left ventricular work index decreased significantly, P < 0.01. Oxygen delivery decreased significantly, P < 0.05. When PEEPe was increased to 100% of PEEPi, stz, the right ventricular work index decreased significantly, P < 0.05.


CONCLUSIONS
Eighty percent of PEEPi, stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.
Kong
W
W
Beijing Chaoyang Hospital-Beijing Institute of Respiratory Medicine, Capital University of Medical Sciences, Beijing 100020, China.
Wang
C
C
Yang
Y
Y
Huang
K
K
Jiang
C
C
D000368:Aged; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D018467:Positive-Pressure Respiration, Intrinsic / Q000503:physiopathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology