This Article Résumé de cet Article Full Text Full Text (PDF) Additional Material Submit a scholarly reply View responses Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Duggan, M. Articles by Kavanagh, B. P. Search for Related Content PubMed PubMed Citation Articles by Duggan, M. Articles by Kavanagh, B. P.

Hypocapnia attenuates mesenteric ischemia-reperfusion injury in a rat model

[L’hypocapnie atténue la lésion mésentérique d’ischémie-reperfusion chez un modèle rat]

Michelle Duggan, MD^*,,, Doreen Engelberts^*, Robert P. Jankov, MD^*,, Jordan M. A. Worrall^¶, Rong Qu, MSc^¶, Gregory M. T. Hare, MD PhD^¶, A. Keith Tanswell, MD^*,, J. Brendan Mullen, MD^|| and Brian P. Kavanagh, MD^*,

^* From the Lung Biology Program, The Research Institute and
the Departments of Critical are Medicine,
Anaesthesia and
Pediatrics, The Hospital for Sick Children;
^¶ the Department of Anesthesia, Cara Phelan Trauma Research Centre, St. Michael’s Hospital; and
^|| the Samuel Lunenfeld Research Institute, Mount Sinai Hospital; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.

Address correspondence to: Dr. Brian Kavanagh, Department of Critical Care Medicine, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. Phone: 416-813-6860; Fax: 416-813-5313; E-mail: brian.kavanagh{at}sickkids.ca

Purpose: Hypocapnia, a recognized complication of high frequency oscillation ventilation, has multiple adverse effects on lung and brain physiology in vivo, including potentiation of free radical injury. We hypothesized that hypocapnia would potentiate the effects of mesenteric ischemia-reperfusion on bowel, liver and lung injury.

Methods: Anesthetized male Sprague-Dawley rats were ventilated with high frequency oscillation and were randomized to one of four groups, exposed to either mesenteric ischemia-reperfusion or sham surgery, and to either hypocapnia or normocapnia.

Results: All animals survived the protocol. Ischemia-reperfusion caused significant histologic bowel injury. Bowel 8-isoprostane generation was greater in ischemia-reperfusion vs sham, but was attenuated by hypocapnia. Laser-Doppler flow studies of bowel perfusion confirmed that hypocapnia attenuated reperfusion following ischemia. Plasma alanine transaminase, reflecting overall hepatocellular injury, was not increased by ischemia-reperfusion but was increased by hypocapnia; however, hepatic isoprostane generation was increased by ischemia-reperfusion, and not by hypocapnia. Oxygenation was comparable in all groups, and compliance was impaired by ischemia-reperfusion but not by hypocapnia.

Conclusion: Hypocapnia, although directly injurious to the liver, attenuates ischemia-reperfusion induced lipid peroxidation in the bowel, possibly through attenuation of blood flow during reperfusion.

eLetters: