Scandinavian journal of clinical and laboratory investigation. Supplementum
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1990
Comparative StudyThe clinical value of the haemoglobin concentration analysis (g/L) and the calculation of oxyhaemoglobin saturation (%) in an automatic blood gas analyser (ABL2, Radiometer A/S, Denmark).
This study was aimed to evaluate the accuracy and thereby the clinical value of the haemoglobin concentration (g/L) analysis and of the calculation of oxyhaemoglobin saturation (%) in a commonly used automatic blood gas analyser (ABL2, Radiometer A/S, Denmark). The measured and calculated values (ABL2) were compared to the readings obtained in a last generation haemoximeter (OSM3, Radiometer A/S, Denmark), which served as reference. ⋯ The oxyhaemoglobin saturation values (%) obtained using the ABL2, however, had a good correlation to the corresponding values measured in the OSM3. It is suggested that the oxyhaemoglobin saturation value obtained in the ABL2 can be used clinically, e.g., for invasive control of pulsoximeters.
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1990
pH effect on the COHb absorption spectrum: importance for calibration of the OSM3 and measurement of circulating hemoglobin and blood volume.
An easy method to measure blood volume is clinically needed. We used carbon monoxide (CO) and the OSM3 to measure circulating hemoglobin and blood volume with the indicator dilution principle. 50 mL of CO was administered into a closed rebreathing system and taken up via the lungs, and the amount of hemoglobin in the blood was calculated from the increase in carboxyhemoglobin fraction after 10 min. ⋯ The bias is 3% COHb per pH unit during calibration of the OSM3, which may be permissible for patients with CO poisoning, but not for the present purpose. With this in mind the method is very accurate, precise and simple.
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1990
Case ReportsThe oxygen status of the arterial blood in the critically ill.
In Critical Care medicine the concepts of Oxygen Delivery, Oxygen Consumption and Tissue Oxygenation have become fundamental in clinical practice but measurements of Oxygen Content and O2 Transport variables require invasive procedures that could be dangerous for critically ill patients and trigger a septic process. Derived indices obtained combining data from a Blood Gas Analyzer with the data from a multi-wavelength spectrophotometer and using the Ole Siggaard-Andersen pH/Blood Gas computerised algorithm might be the non-invasive answer. On 115 arterial blood samples from critically ill patients, we measured pH, pCO2, pO2, oxygen saturation, total hemoglobin concentration and fractions of carboxy- and methemoglobin. ⋯ The correlation between p50 calculated by the Ole Sigaard-Andersen algorithm with that derived from classical formula shows the superiority of the findings obtained by means of the new algorithm. In critically ill patients the ODC is usually shifted to the right. The new parameters, pO2uv- and CQ, contain useful informations for clinical practise; but rapid changes in Cardiac Index (CI) and VO2/m2 can be ignored by the new algorithm, if these changes are not associated with a rise in ctO2 or pH and pCO2 changes.(ABSTRACT TRUNCATED AT 400 WORDS)
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Scand. J. Clin. Lab. Invest. Suppl. · Jan 1990
Accurate measurements of hemoglobin oxygen saturation, and fractions of carboxyhemoglobin and methemoglobin in fetal blood using Radiometer OSM3: corrections for fetal hemoglobin fraction and pH.
The differences in the visible absorption spectra between fetal and adult oxyhemoglobin and carboxyhemoglobin result in errors in the measurements og hemoglobin oxygen saturation (SO2) and carboxyhemoglobin fraction (FCOHb) in fetal blood, if not corrected for the actual fetal hemoglobin fraction (FHbF) in the sample. In 11 fully oxygenated umbilical cord blood samples (mean FHbF = 77%), we found a mean positive bias in SO2 of 4.7%, and in FCOHb of 2.7%, when measured with a dedicated spectrophotometer (OSM3, Radiometer A/S, Denmark), and using the matrix of absorption coefficients for adult hemoglobin. Accurate measurements were obtained by using OSM3's correction for FHbF in the blood specimen after measurement of FHbF by OSM3. ⋯ FHbF measured by OSM3 at pH 7.4 is about 14% too high compared to alkali denaturation rate method. However, the presence of a metabolic acidemia, which is common in fetal blood specimens, decreases this bias, so that for example in our study, FHbF, measured by OSM3 and uncorrected for pH changes was on average only 6% too high. We recommend that OSM3's factor of 18.6 is reduced to 16.4, and that correction is made for pH.