title: Critical oxygen delivery in conscious septic rats under stagnant or anemic hypoxia.
abstract: Although evidence shows that critical O2 delivery (QO2crit), the point at which oxygen consumption becomes limited by O2 delivery (QO2), is not affected by the method used to decrease QO2 in healthy subjects, microcirculatory injury caused by sepsis may modify QO2crit in a unique manner. We therefore designed this study to compare QO2crit in anemic and stagnant hypoxia in conscious septic rats. Rats were randomized to control or sepsis induced by cecal ligation and perforation; 24 hours later, oxygen consumption was measured using expired gas analysis, whereas QO2 was calculated from standard formula. Rats were further randomized to anemic hypoxia by isovolemic hemodilution or stagnant hypoxia by stepwise inflation of a balloon-tip catheter in the right atrium. QO2crit and critical hemoglobin concentration were calculated by dual linear regression analysis. We found that (1) QO2crit was not different between anemic and stagnant hypoxia in sepsis and that (2) the critical hemoglobin concentration in anemic hypoxia was similar between sepsis and control, indicating that tolerance to acute anemia is not altered by sepsis. Further studies are needed before the clinical relevance of these conclusions can be fully understood.
authors.affiliation: London Health Sciences Centre, 375 South Street, London, ON, Canada N6A 4G5.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Morita
authors.forename: Ian
authors.initials: I
authors.lastname: Chin-Yee
authors.forename: Pei
authors.initials: P
authors.lastname: Yu
authors.forename: William J
authors.initials: WJ
authors.lastname: Sibbald
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Martin
mesh_terms: D000208:Acute Disease; D000740:Anemia / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001784:Blood Gas Analysis; D001944:Breath Tests; D002302:Cardiac Output; D002432:Cecum / Q000293:injuries; D003243:Consciousness; D016638:Critical Illness; D004195:Disease Models, Animal; D006438:Hemodilution; D006454:Hemoglobins / Q000032:analysis; D000860:Hypoxia / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D007416:Intestinal Perforation / Q000150:complications; D008026:Ligation; D016014:Linear Models; D008297:Male; D008833:Microcirculation; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D010101:Oxygen Consumption; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D006454:Hemoglobins; D010100:Oxygen