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The Scientific World Journal
Volume 2012, Article ID 410321, 6 pages
http://dx.doi.org/10.1100/2012/410321
Clinical Study

Hyperoxia Reversibly Alters Oxygen Consumption and Metabolism

1Department of Anesthesiology and Intensive Care Medicine, Tübingen University Hospital, Eberhard-Karls University, 72076 Tübingen, Germany
2Clinic of Anesthesiology, Intensive Care Medicine, and Pain Control, Nord-West Hospital, 60488 Frankfurt, Germany
3Clinic of Anesthesiology, Intensive Care Medicine and Pain, Therapy Goethe-University Hospital Center, 60590 Frankfurt, Germany

Received 14 November 2011; Accepted 22 December 2011

Academic Editors: B. Bein and A. J. Kirtane

Copyright © 2012 Patrick Lauscher et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aim. Ventilation with pure oxygen (hyperoxic ventilation: HV) is thought to decrease whole body oxygen consumption (VO2). However, the validity and impact of this phenomenon remain ambiguous; until now, under hyperoxic conditions, VO2 has only been determined by the reverse Fick principle, a method with inherent methodological problems. The goal of this study was to determine changes of VO2, carbon dioxide production (VCO2), and the respiratory quotient (RQ) during normoxic and hyperoxic ventilation, using a metabolic monitor. Methods. After providing signed informed consent and institutional acceptance, 14 healthy volunteers were asked to sequentially breathe room air, pure oxygen, and room air again. VO2, VCO2, RQ, and energy expenditure (EE) were determined by indirect calorimetry using a modified metabolic monitor during HV. Results. HV reduced VO2 from 3.4 (3.0/4.0) mL/kg/min to 2.8 (2.5/3.6) mL/kg/min (𝑃<0.05), whereas VCO2 remained constant (3.0 [2.6/3.6] mL/kg/min versus 3.0 [2.6/3.5] mL/kg/min, n.s.). After onset of HV, RQ increased from 0.9 (0.8/0.9) to 1.1 (1.0/1.1). Most changes during HV were immediately reversed during subsequent normoxic ventilation. Conclusion. HV not only reduces VO2, but also increases the respiratory quotient. This might be interpreted as an indicator of the substantial metabolic changes induced by HV. However, the impact of this phenomenon requires further study.