Influence of abdominal pressure and sympathetic vasoconstriction on the cardiovascular response to positive end-expiratory pressure

Am Rev Respir Dis. 1977 Oct;116(4):661-70. doi: 10.1164/arrd.1977.116.4.661.

Abstract

The role of changes in abdominal pressure and sympathetically mediated vasoconstriction in the cardiovascular response to positive end-expiratory pressure was evaluated in 9 mongrel dogs. When the abdomen was widely opened, the decrease in cardiac output caused by positive end-expiratory pressure was the same as that found during control studies. When the abdomen was tightly bound, cardiac output was higher at any positive end-expiratory pressure than in control state (P less than 0.01), but the percent decrease produced by increasing positive end-expiratory pressure was the same. alpha-Adrenergic blockade with phenoxybenzamine produced a significantly greater decrease in cardiac output at any given positive end-expiratory pressure and thus appeared to inhibit the previously operative peripheral vascular adjustments to positive end-expiratory pressure. The major compensatory mechanism in the cardiovascular response to positive end-expiratory pressure thus appears to be mediated via alpha-adrenergic sympathetic factors.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Abdomen
  • Animals
  • Blood Pressure
  • Cardiac Output* / drug effects
  • Dogs
  • Heart / physiology
  • Heart Atria
  • Phenoxybenzamine / pharmacology
  • Positive-Pressure Respiration*
  • Pressure
  • Pulmonary Artery
  • Thorax / physiology*
  • Vasomotor System / physiology*

Substances

  • Phenoxybenzamine