Affordable Access

Publisher Website

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

  • Horn, Andrew G1
  • Baumfalk, Dryden R1
  • Schulze, Kiana M1
  • Kunkel, Olivia N1
  • Colburn, Trenton D1
  • Weber, Ramona E1
  • Bruells, Christian S2
  • Musch, Timothy I1, 3
  • Poole, David C1, 3
  • Behnke, Bradley J1
  • 1 Department of Kinesiology, Kansas State University, Manhattan, Kansas.
  • 2 Department of Anesthesiology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany. , (Germany)
  • 3 Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas.
Published Article
Journal of Applied Physiology
American Physiological Society
Publication Date
Sep 01, 2020
DOI: 10.1152/japplphysiol.00320.2020
PMID: 32730173


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


Seen <100 times