The cardiovascular effects of normobaric hyperoxia in patients with heart rate fixed by permanent pacemaker

Anderson, K.J., Harten, J.M., Booth, M.G., Berry, C., McConnachie, A. , Rankin, A.C. and Kinsella, J. (2010) The cardiovascular effects of normobaric hyperoxia in patients with heart rate fixed by permanent pacemaker. Anaesthesia, 65(2), pp. 167-171. (doi:10.1111/j.1365-2044.2009.06195.x)

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Abstract

To investigate whether the established reductions in heart rate and cardiac output with hyperoxia in humans are primary effects or secondary to increases in systemic vascular resistance, we paced the hearts of nine patients with permanent pacemakers at a fixed rate when breathing either medical air (inspired O2 fraction 0.21) or oxygen (inspired O2 fraction 0.80) in a randomised, double-blind fashion. A thoracic bio-impedance machine was used to measure heart rate, stroke volume and blood pressure and calculate cardiac index and systemic vascular resistance index. Oxygen caused no change in cardiac index (p = 0.18), stroke index (p = 0.44) or blood pressure (p = 0.52) but caused a small (5.5%) increase in systemic vascular resistance index (p = 0.03). This suggests that hyperoxia has no direct myocardial depressant effects, but that the changes in cardiac output reported in previous studies are secondary to changes in systemic vascular resistance.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McConnachie, Professor Alex and Rankin, Professor Andrew and Harten, Dr Johann and Kinsella, Professor John and Booth, Dr Malcolm and Anderson, Dr Keith
Authors: Anderson, K.J., Harten, J.M., Booth, M.G., Berry, C., McConnachie, A., Rankin, A.C., and Kinsella, J.
Subjects:R Medicine > R Medicine (General)
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Robertson Centre
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College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Clinical Specialities
Journal Name:Anaesthesia
ISSN:0003-2409
ISSN (Online):1365-2044
Published Online:09 December 2009

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