Vh. Larsen et O. Siggaardandersen, THE OXYGEN STATUS ALGORITHM ONLINE WITH THE PH BLOOD-GAS ANALYZER, Scandinavian journal of clinical & laboratory investigation, 56, 1996, pp. 9-19
Background: The Oxygen Status Algorithm is a computer program for inte
rpretation of pH-blood gas measurements. Recently the facility for on-
line transfer of measured data from the pH-blood gas analyzer (ABL 520
) to the computer with instant calculation, graphical display, and pri
nt-out of the oxygen status and the acid-base status of the blood has
been implemented. Objective: To describe experiences with routine appl
ication of the Oxygen Status Algorithm in an intensive care unit acid
to describe recent improvements of the program. Data sources: Routine
pH-blood gas analyses during a two year period with an average of 40 a
nalyses per day. Results: Several unexpected results were disclosed, e
specially with respect to abnormal haemoglobin-oxygen affinity, causin
g suspicion of low 2,3-diphosphoglycerate concentration and hypophosph
atemia. The criteria for routine administration of oxygen could be rev
ised on the basis of the oxygen extraction tension. The program was ex
panded to allow the printing of a cumulated patient report, and modifi
ed to allow calculation of the oxygen consumption rate on the basis of
simultaneous measurements on the arterial and the mixed venous blood.
The program and the computer hardware functioned well in continuous o
peration during the whole study. It proved to be difficult, however, t
o ensure that all measurements were supplemented by information on the
patient temperature and the fraction of inspired oxygen. Conclusion:
The Oxygen Status Algorithm provides a more detailed description of th
e oxygen status and the acid-base status of the blood than currently e
mployed. The interaction between the arterial oxygen tension, the haem
oglobin oxygen capacity and the haemoglobin oxygen affinity is display
ed graphically and the degree of compensation among these three proper
ties is expressed in terms of a single quantity: the oxygen extraction
tension. The program also provides an interactive interpretation, all
owing a rapid prediction of the expected effect of therapeutic interve
ntion. Nevertheless, implementation of the program in the daily routin
e requires an intensive educational effort among physicians as well as
nurses and laboratory technicians.