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The accuracy of pulse oximetry at two haematocrit levels
Author(s) -
Vegfors M.,
Lindberg L. G.,
Öberg P. Å.,
Lennmarken C.
Publication year - 1992
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1992.tb03496.x
Subject(s) - pulse oximetry , medicine , pulse (music) , anesthesia , oxygen saturation , saturation (graph theory) , oxygen , cardiology , optics , chemistry , physics , mathematics , organic chemistry , combinatorics , detector
The object of this study was to investigate the influence of haematocrit on the accuracy of pulse oximetry. Seven Swedish land race rabbits were studied. The oxygen saturation of haemoglobin was decreased stepwise using increasing fractions of nitrogen to the inspiratory gas. One pulse oximeter probe was attached on the front leg and another probe directly over the common carotid artery. The pulse oximeter readings (Spo 2 ) were compared with simultaneous oxygen saturation analysis (Sao 2 ) by a haemoximeter. The pulse oximeter measurements were performed at the haematocrit levels of approximately 40% and 11%, respectively. We found a good correlation between Spo 2 and Sao 2 in a wide range of the oxygen saturation, i.e. Sao 2 26–100%. After haemodilution the correlation was improved in the range 86–100%, but not in the range 26–85%. No correlation between Spo 2 and Sao 2 was found when the sensor was attached directly over the artery during normal haematocrit levels. After haemodilution a better correlation was however obtained. These results indicate that the accuracy of pulse oximetry is dependent on the haematocrit level.