Affordable Access

deepdyve-link
Publisher Website

Effects of elevated positive end-expiratory pressure on diaphragmatic blood flow and vascular resistance during mechanical ventilation

Authors
  • Horn, Andrew G.1
  • Baumfalk, Dryden R.1
  • Schulze, Kiana M.1
  • Kunkel, Olivia N.1
  • Colburn, Trenton D.1
  • Weber, Ramona E.1
  • Bruells, Christian S.2
  • Musch, Timothy I.1, 1
  • Poole, David C.1, 1
  • Behnke, Bradley J.1
  • 1 Kansas State University, Manhattan, Kansas
  • 2 RWTH Aachen University, Aachen , (Germany)
Type
Published Article
Journal
Journal of Applied Physiology
Publisher
American Physiological Society
Publication Date
Jul 30, 2020
Volume
129
Issue
3
Pages
626–635
Identifiers
DOI: 10.1152/japplphysiol.00320.2020
PMID: 32730173
PMCID: PMC7517429
Source
PubMed Central
Keywords
Disciplines
  • Research Article
License
Unknown

Abstract

Although mechanical ventilation (MV) is a life-saving intervention, prolonged MV can lead to deleterious effects on diaphragm function, including vascular incompetence and weaning failure. During MV, positive end-expiratory pressure (PEEP) is used to maintain small airway patency and mitigate alveolar damage. We tested the hypothesis that increased intrathoracic pressure with high levels of PEEP would increase diaphragm vascular resistance and decrease perfusion. Female Sprague-Dawley rats (~6 mo) were randomly divided into two groups receiving low PEEP (1 cmH2O; n = 10) or high PEEP (9 cmH2O; n = 9) during MV. Blood flow, via fluorescent microspheres, was determined during spontaneous breathing (SB), low-PEEP MV, high-PEEP MV, low-PEEP MV + surgical laparotomy (LAP), and high-PEEP MV + pneumothorax (PTX). Compared with SB, both low-PEEP MV and high-PEEP MV increased total diaphragm and medial costal vascular resistance ( P ≤ 0.05) and reduced total and medial costal diaphragm blood flow ( P ≤ 0.05). Also, during MV medial costal diaphragm vascular resistance was greater and blood flow lower with high-PEEP MV vs. low-PEEP MV ( P ≤ 0.05). Diaphragm perfusion with high-PEEP MV+PTX and low-PEEP MV were not different ( P > 0.05). The reduced total and medial costal diaphragmatic blood flow with low-PEEP MV appears to be independent of intrathoracic pressure changes and is attributed to increased vascular resistance and diaphragm quiescence. Mechanical compression of the diaphragm vasculature may play a role in the lower diaphragmatic blood flow at higher levels of PEEP. These reductions in blood flow to the quiescent diaphragm during MV could predispose critically ill patients to weaning complications. NEW & NOTEWORTHY This is the first study, to our knowledge, demonstrating that mechanical ventilation, with low and high positive-end expiratory pressure (PEEP), increases vascular resistance and reduces total and regional diaphragm perfusion. The rapid reduction in diaphragm perfusion and increased vascular resistance may initiate a cascade of events that predispose the diaphragm to vascular and thus contractile dysfunction with prolonged mechanical ventilation.

Report this publication

Statistics

Seen <100 times