Optimizing oxygen delivery is an important part of the hemodynamic resuscitation of septic shock, but concerns have been raised over the potentially deleterious effects of hyperoxia. We evaluated the impact of hyperoxia on hemodynamics, the microcirculation, and cerebral and renal metabolism in an ovine model of septic shock.
Randomized animal study.
University hospital animal research laboratory.
Fourteen adult female sheep.
After induction of fecal peritonitis, sheep were randomized to ventilation with an FIO2 of 100% (n = 7) or an FIO2 adjusted to maintain PaO2 between 90 and 120 mm Hg (n = 7, control). All animals were fluid resuscitated and observed until death.
In addition to hemodynamic measurements, we assessed the sublingual microcirculation, renal and cerebral microdialysis and microvascular perfusion, and brain tissue oxygen pressure. Hyperoxic animals initially had a higher mean arterial pressure than control animals. After onset of shock, hyperoxia blunted the decrease in stroke volume index observed in the control group. Hyperoxia was associated with a higher sublingual microcirculatory flow over time, with higher cerebral perfusion and brain tissue oxygen pressure and with a lower cerebral lactate-to-pyruvate ratio than in control animals. Hyperoxia was also associated with preserved renal microvascular perfusion, lower renal lactate-to-pyruvate ratio, and higher PaO2/FIO2 ratio.
In this acute peritonitis model, hyperoxia induced during resuscitation provided better hemodynamics and peripheral microvascular flow and better preserved cerebral metabolism, renal function, and gas exchange. These observations are reassuring with recent concerns about excessive oxygen therapy in acute diseases.
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1Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
2Department of Intensive Care, Sun Yat-sen University Cancer Center, Guangzhou, China.
3Anesthesia and Intensive Care B, Department of Surgery, Dentistry, Pediatrics and Gynecology, University of Verona, AOUI-University Hospital Integrated Trust of Verona, Verona, Italy.
*See also p. 1796.
Dr. He designed and conducted the experiment, acquired and analyzed the data, and drafted the article; Dr. Su designed and directed the protocol; Dr. Xie helped perform the experiments and acquire the data; Dr. Taccone helped perform the experiments, interpret the data, and draft the article; Dr. Donadello helped perform the experiments; and Dr. Vincent was involved in the study design. Drs. Su, Xie, Taccone, Donadello, and Vincent critically revised the article.
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The authors have disclosed that they do not have any potential conflicts of interest.
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