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

Abstract

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.

Retrospective Analysis of Pneumothorax After Repair of Esophageal Atresia/Tracheoesophageal Fistula: A Case Control Study

“…Greenough [19] believed that neonates should be subjected to simultaneous mechanical ventilation at a lower PIP to reduce lung trauma, air leakage, bronchopulmonary dysplasia and other problems. Horn [20] found that high PEEP would lead to reduced blood perfusion in the diaphragmatic muscle, thus affecting respiration in animal experiments. In summary, the relationship between mechanical ventilation and pneumothorax still needs further studies to explore.…”

Prolonged mechanical ventilation increases diaphragm arteriole circumferential stretch without changes in stress/stretch: Implications for the pathogenesis of ventilator‐induced diaphragm dysfunction

“…To estimate shear stress, we used previously established in vivo medial costal diaphragm blood flow data from several studies 2,12,14 (Table 1) combined with in vitro vasomotor studies on isolated medial costal diaphragm blood vessels. We chose this approach due to the inability to perform both blood flow and isolated vessel experiments in the same tissue of the same animal (see Appendix for detailed methods).…”

“…In each animal, 1As arterioles from the medial costal diaphragm were used for the isolated vessel experiments and underwent passive‐pressure response experiments (described below). We chose to study medial costal diaphragm 1As, as the medial costal diaphragm receives the highest mass‐specific blood flow within the costal diaphragm 2,12,14,22 and previous research demonstrates MV‐induced vascular dysfunction in medial costal diaphragm 1As 4 …”

“…A perturbed mechanical stimulation, such as diminished flow and shear stress, can lead to rapid (eg, within minutes) structural adaptations of the vessel wall (ie, inward vascular remodeling) 11 . The diminished perfusion and elevated vascular resistance in the diaphragm vasculature during MV 2,12 may instigate structural adaptations such as inward vascular remodeling in diaphragm resistance vessels.…”

“…Prolonged vasoconstriction (ie, 4 h) of arterioles is associated with VSMC repositioning within the vascular wall (eg, intimal migration and proliferation), 16,17 and it has been suggested that these changes are mediated by matrix metalloproteinase activation 18,19 . Interestingly, within 10 min of quiescence with MV, diaphragm vascular resistance is increased, and perfusion is reduced, likely due to arteriolar vasoconstriction, 12 which persists with prolonged MV 2 . Given that the diaphragm is never quiescent in vivo, the contracting condition reflects “homeostasis,” such that diaphragm inactivity and reduced diaphragm flow during MV may induce rapid vascular remodeling.…”