Study objective: To determine whether the presence of an indwelling ar
terial access line leads to differences in blood-drawing practices and
costs, in patients with similar APACHE II scores, in the ICU. Design:
Prospective, observational. Setting: Adult surgical and medical ICUs
at a large military tertiary care hospital. Patients: Twenty-five adul
t tie, above 18 years old) patients with arterial access lines and 25
adult patients without arterial access lines. Each had APACHE II of 9
to 20 and none had any central venous access. Measurements and results
: A survey of the arterial line blood-drawing habits of critical care
nurses at our hospital revealed a 2.99-mL mean discard blood volume to
clear an arterial line, with only 9.4% not discarding any blood. For
each patient enrolled in the study, the number of blood tests and bloo
d draws were recorded during the first two 24-h periods after admissio
n to the ICU. The amount of blood required by the laboratory for each
blood test was totalled. In the arterial line group, the mean discard
volume was added to the total for each blood-drawing procedure. Increa
ses were found in the number of blood tests (29% increase, p = 0.013),
blood-drawing procedures (30% increase, p = 0.014), and the amount of
blood volume (44% increase, p < 0.001) sent from patients with arteri
al lines compared to those without. Conclusion: When APACHE II scores
are similar, the presence of an arterial access line may lead to incre
ased blood drawing from patients in ICUs.