Circulation, Vol 72, 660-667, Copyright © 1985 by American Heart Association
RV Ditchey, J Lindenfeld, EW Grogan and GO Zerbe
Based on the observation that positive end-expiratory airway pressure
(PEEP) causes comparable increments in intrapericardial and right-sided
intracardiac pressures, we hypothesized that intracavitary left ventricular
filling pressures measured in the presence of PEEP can be corrected for
increased intrathoracic pressure by subtracting the effects of PEEP on
intracavitary right ventricular filling pressures. Ventricular function
curves (aortic blood flow vs intracavitary left ventricular end-diastolic
pressure [LVEDP]) were generated with and without 15 cm of water of PEEP in
eight dogs. All curves were shifted to the right by PEEP (i.e.,
intracavitary LVEDP was higher for any submaximal level of aortic blood
flow). However, when pressures measured in the presence of PEEP were
"corrected" by subtracting the corresponding increment in intracavitary
right ventricular end- diastolic pressure caused by PEEP at each level of
ventricular filling, control and corrected PEEP data points appeared to
fall on the same curve in five dogs, and differed only slightly in three
dogs. Mean control and corrected PEEP curves derived by averaging
polynomial regression coefficients for each condition differed
significantly from uncorrected PEEP curves (p less than .05), but not from
each other. Analogous curves based on mean left atrial pressure were
corrected equally well by subtracting the effects of PEEP on mean right
atrial pressure. We conclude that the increments in intracavitary right
heart filling pressures caused by PEEP can be used to correct intracavitary
left heart filling pressures for the effects of PEEP on intrathoracic
pressure.
ARTICLES
A potential method of correcting intracavitary left ventricular filling pressures for the effects of positive end-expiratory airway pressure
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