Scandinavian journal of clinical and laboratory investigation. Supplementum
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1996
Review Comparative StudySimultaneous measurement of total hemoglobin and its derivatives in blood using CO-oximeters: analytical principles; their application in selecting analytical wavelengths and reference methods; a comparison of the results of the choices made.
Optical methods of quantifying total hemoglobin (tHb), applying the principles of the Lambert-Beer law, have been used both on untreated whole blood and on blood mixed with chemicals to form a stable chromophore, since the earliest days of laboratory medicine. The same principles may be applied for quantitation of the individual hemoglobin derivatives, such as oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb)1, as well as the non-oxygen transporting "dyshemoglobins", including carboxyhemoglobin (COHb) and methemoglobin (MetHb). The total hemoglobin measurement is typically carried out using a light source with a broad band of visible wavelengths. ⋯ Either general-purpose, narrow band-pass spectrophotometers, or special-purpose photometers utilizing a set of fixed wavelengths, commonly referred to as "CO-oximeters" are suitable. Rapid, direct, photometric quantification of the derivatives, necessary in the clinical environment, relies on the specific light absorption characteristics of each hemoglobin derivative at the wavelengths selected, which in turn requires independent and exact knowledge of the concentrations of each entity in reference materials. This report examines the process involved in the selection of wavelengths and reference methods, contrasts the effects of the choices made and discusses some implications and limitations for routine measurement.
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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.
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1991
Evaluation of TATI and other markers in solid tumors.
The usefulness of tumor-associated trypsin inhibitor (TATI) in the diagnosis of various solid tumors was compared to other tumor markers occurring in serum and urine (CEA, CA19-9, CA125, CA72-4, CA50, CA15-3, CA72-4, NSE, TPA, AFP, CK-BB and ferritin). TATI was particularly well suited for the diagnosis of tumors of the pancreas, ovary, oesophagus and bladder. For tumors of these organs TATI may be considered the marker of choice. TATI was also a good marker for distinguishing between disease with or without liver metastasis in cancer of the colon and the breast.