Bedside diagnostic blood testing. Its accuracy, rapidity, and utility in blood conservation
M. Salem, B. Chernow, R. Burke, J. A. Stacey, M. Slogoff and S. Sood
Department of Medicine, Sinai Hospital of Baltimore, MD 21215.
OBJECTIVE.--Bedside diagnostic testing utilizing microchemistry instruments
potentially offers physicians the opportunity to evaluate urgent blood test
results rapidly and reliably using only drops (250 microL) of whole blood.
The use of microchemistry technology may also represent an essential
component of a blood conservation program in acutely ill patients. We
tested the hypothesis that a microchemistry instrument would have important
advantages in the intensive care unit, including rapid turnaround time,
decreased iatrogenic blood loss, and the provision of accurate analyte
results. DESIGN.--One-year prospective, random-sample comparative study.
SETTING.--A tertiary, acute care, 1000-bed university teaching hospital and
a 450-bed university-affiliated community hospital. PATIENTS.--Blood
samples from 850 patients were analyzed. RESULTS.--There were strong
correlations (for pH, R2 = .97; PCO2, R2 = .97; PO2, R2 = .99; sodium, R2 =
.83; potassium, R2 = .94; chloride, R2 = .90; glucose, R2 = .98; and
hematocrit, R2 = .92) when paired samples were analyzed simultaneously in
the laboratory comparing the microchemistry instrument and currently
accepted clinical laboratory instruments. There were significant
correlations (for pH, R2 = .91; PCO2, R2 = .94; PO2, R2 = .97; sodium, R2 =
.91; potassium, R2 = .86; chloride, R2 = .91; ionized calcium, R2 = .82;
glucose, R2 = .96; and hematocrit, R2 = .75) but increased variability
occurred in some analyte results when samples were first analyzed in the
intensive care unit (using the microchemistry instrument) and then
transported to the laboratory in the routine fashion for "stat"
determinations. CONCLUSIONS.--The multichannel microchemistry instrument
provided accurate analyte determinations when compared with accepted
clinical laboratory instruments. Significant savings of time and blood were
also realized by the use of a microchemistry instrument in the intensive
care unit. Bedside microchemistry may provide clinically important
advantages in emergency departments, operating rooms, and neonatal,
pediatric, coronary, adult medical and surgical, trauma, and burn intensive
care units.
