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Oxygen status algorithm, version 3, with some applications
Author(s) -
SIGGAARDANDERSEN M.,
SIGGAARDANDERSEN O.
Publication year - 1995
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.1399-6576.1995.tb04324.x
Subject(s) - hyperventilation , medicine , oxygen , pco2 , arterial oxygen tension , oxygen saturation , arterial blood , anesthesia , analyser , oxygen tension , venous blood , algorithm , chromatography , chemistry , computer science , lung , organic chemistry
The Oxygen Status Algorithm is a computer program which uses measurements from a pH & blood gas analyser and a haemoximeter to calculate the oxygen status and the acid‐base status of the arterial blood. Version 3 features on‐line data collection from the analyser; storage of up to 2000 patient cases in a Lotus 123 file format; printing of a Cumulated Patient Report in addition to the Patient Status Report; combination of arterial and mixed venous data for calculation of the shunt and the oxygen consumption rate (when cardiac output is keyed in); calculation of reference values for fetal haemoglobin for newborns (when gestational age is keyed in). Examples of applications answer the following questions:1) Does hyperventilation improve the oxygen supply to the tissues? No, for a normal person a slight hypoventilation with a p CO 2 of 8. 5 kPa provides a maximal oxygen extraction tension. 2) What is the optimal hyperventilation at the top of Mt. Everest (ambient pressure 33 kPa)? Hyperventilation to a p CO 2 of about 1. 4 kPa provides a maxima] oxygen extraction tension of 2. 4 kPa for an unacclimatized person. 3) Which change in haemoglobin oxygen affinity would be equivalent to a decrease in arterial p O, to 6. 3 kPa? The oxygen extraction tension would decrease to 4. 0 kPa and the same value would be caused by a decrease in half‐saturation tension to 2. 8 kPa, a decrease which could be due to a moderate alkalaemia (pH = 7. 54) combined with a moderately decreased 2, 3‐diphosphoglycerate concentration (3. 4 mmol/L). 4) Is temperature correction of the measured p O 2 and p CO 2 to the actual body temperature needed? Yes, for example, omitting temperature correction even when the patient temperature is only slightly decreased to 36 °C would result in a negative value for the calculated arterio‐venous shunt fraction when the actual value, using temperature correction, is 11%. 5) Does the alpha‐stat approach of p CO 2 and pH regulation in hypothermia, where pH is allowed to rise as in blood in vitro , cause a fall in mixed venous p O 2 below the critical value? No, although the mixed venous p O 2 will be lower than with the pH‐stat approach (constant pH at body temperature), it remains above the critical mixed venous p O 2 level.The program is intended for clinical routine use as well as teaching purposes. It has context sensitive help as well as an extensive help index. A number of “demo” cases are provided with annotations in a separate file.