The Annals of Thoracic Surgery, Vol 26, 62-67, Copyright © 1978 by The Society of Thoracic Surgeons
Experimental pulmonary edema: the effect of positive end-expiratory pressure on lung water
CE Bredenberg, T Kazui and WR Webb
The effect of 10 cm of positive end-expiratory pressure (PEEP) on lung
water was studied during pulmonary edema induced in dogs by inflating a
Foley balloon placed in the left atrium. Colloid oncotic pressure (COP) was
measured directly. Intrapleural pressure (IPP) was measured after surgical
closure of the chest. Transmural left atrial (LA) pressure (LA minus IPP)
minus COP was considered to be the net force driving water out of the
capillaries. LA pressure was elevated so that transmural LA pressure minus
COP averaged +7.5 mm Hg. Water accumulation was expressed as the ratio of
wet to dry weight. The control ratio of wet to dry lung weight was 4.30 +/-
0.10 (+/- SE). After 2 hours of standardized pulmonary edema and
ventilation without PEEP, wet-to-dry lung weight was 5.63 +/- 0.24. In
animals ventilated with 10 cm of PEEP through 2 hours of pulmonary edema
the ratio was 5.36 +/- 0.14. Animals ventilated with 10 cm of PEEP showed a
significant increase in functional residual capacity and decreased
intrapulmonary shunt. Ten centimeters of PEEP, however, had no
statistically significant effect on water accumulation during experimental
pulmonary edema.
