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Effects of positive end‐expiratory pressure on intestinal circulation during graded mesenteric artery occlusion
Author(s) -
Lehtipalo S.,
Biber B.,
Fröjse R.,
Arnerlöv C.,
Johansson G.,
Winsö O.
Publication year - 2001
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.2001.045007875.x
Subject(s) - medicine , perfusion , superior mesenteric artery , oxygenation , cardiac output , circulatory system , hemodynamics , anesthesia , ischemia , blood flow , positive end expiratory pressure , cardiology , mechanical ventilation
Background: Reduced gut perfusion is associated with multiple organ failure. Positive end‐expiratory pressure (PEEP) reduces cardiac output (CO) and portal blood flow, and might be detrimental in a situation of already compromised intestinal circulation. The aim of this study was to investigate regional circulatory and metabolic effects of PEEP during graded regional hypoperfusion. Methods: In 12 barbiturate‐anesthetized pigs, we measured systemic and regional blood flows (superior mesenteric arterial, Q SMA and portal venous, Q PORT ), jejunal mucosal perfusion (LDF), tissue oxygenation (PO 2TISSUE ) and metabolic parameters at PEEP (0, 4, 8 and 12 cm H 2 O) in a randomized order. Measurements were performed at unrestricted intestinal perfusion pressures (IPP) and at IPP levels of 50 and 30 mmHg. Results: During unrestricted IPP, PEEP decreased MAP, CO, Q SMA and Q PORT , while systemic, and preportal (R PORT ) vascular resistances and jejunal mucosal perfusion were not significantly changed. Preportal tissue oxygen delivery and PO 2TISSUE decreased, while preportal tissue oxygen uptake was unaltered. During restricted IPP, PEEP produced the same pattern of hemodynamic alterations as when IPP was not restricted. Q PORT and Q SMA were lowered by the reductions in IPP, and Q PORT was further reduced during PEEP. At an IPP of 30 mmHg, this reduction in Q PORT decreased preportal tissue oxygen uptake. Consequently, intestinal ischemia, as indicated by increased net lactate production, occurred. Simultaneously, jejunal mucosal perfusion and PO 2TISSUE declined. Conclusion: At IPP levels below 50 mmHg, even moderate levels of PEEP impaired local blood flow enough to cause intestinal ischemia. Our data underscore the importance of considering regional circulatory adaptations during PEEP ventilation.