Scandinavian journal of clinical and laboratory investigation. Supplementum
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1993
The TANH-equation modified for the hemoglobin, oxygen, and carbon monoxide equilibrium.
The model of the hemoglobin-oxygen equilibrium represented by the TANH-equation is incorporated in the Oxygen Status Algorithm, a computer program for calculating and displaying the oxygen status and the acid-base status of the blood. In the presence of carbon monoxide it is necessary to take the Haldane equation into account. We here describe the necessary equations and methods for iterative solutions. ⋯ We have performed a few experiments to confirm this. Like Zwart et al. we find a small deviation from the theory, but in the opposite direction, i.e. the measured p50 values are slightly higher than predicted. We conclude that the Haldane equation adequately accounts for the carbon monoxide effect up to 30% carboxy-hemoglobin, but further studies are needed to confirm or exclude any minor deviation from the Haldane relationship which may be significant at higher carboxy-hemoglobin fractions.
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1993
Historical ArticleHistory and recent developments in pulse oximetry.
To honour Siggaard-Andersen's role in the development of accurate blood oximetry, this paper was abstracted from a recent review and survey of over 750 publications of pulse oximetry. Pulse oximetry usage has become nearly universal during anesthesia and related critical care in the developed world during the last decade. More than 35 manufacturers offer pulse oximetry. ⋯ New developments include better understanding of management of premature infants, beginning use for fetal SaO2 during labor, sophisticated methods of ignoring motion artifacts and room light interference, and awareness of sources of error. Oximetry use has caused anesthesiologists and most critical care physicians to become far more able to avoid severe hypoxia in patients. Malpractice insurance rates for anesthesiologists have dropped in the USA, and other evidence suggests, although failing to prove, that anesthesia and critical care is now safer, probably due to oximetry.