The effect of arterial lines on blood-drawing practices and costs in intensive care units.

STUDY OBJECTIVE To determine whether the presence of an indwelling arterial 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 adult (ie, 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 blood draws were recorded during the first two 24-h periods after admission 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. Increases 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 arterial lines compared to those without. CONCLUSION When APACHE II scores are similar, the presence of an arterial access line may lead to increased blood drawing from patients in ICUs.