ABGS AND ARTERIAL LINES - THE RELATIONSHIP TO UNNECESSARILY DRAWN ARTERIAL BLOOD-GAS SAMPLES

Arterial blood gas measurements (ABGs) are the most common tests ordered in an ICU. ABG utilization in a surgical ICU over a 1-year period (September 1,1987—October 31, 1988) was evaluated to identify factors that might help reduce overutilization. A total of 842 admissions comprising 2,381 patient days were reviewed. ABGs were the most commonly ordered test (mean of 4.8/ patient/day). Patients with arterial lines (A-lines) had more ABGs drawn than those who did not regardless of the value of PaO2 (p < 0.01), PaCO2 (p < 0.01 except for PaCO2 > 55), APACHE II score (p < 0.01), use of ventilators (p < 0.01), pulse oximeters (p < 0.01), or a combination of the last two (p < 0.01). Multivariate analysis demonstrated that the presence of an A-line was the most powerful predictor of the number of ABGs drawn per patient (p < 0001) independent of all other measures of the patient’s clinical status such as the use of ventilators, oximeters, and values of PaO2, PaCO2, or the APACHE II score. This suggests that ABGs are being drawn unnecessarily simply because of the presence of an A-line. To reduce the number of ABGs drawn, a policy for specific indications for placement of A-lines and ABG analysis should be adopted. © 1990 by The Williams & Wilkins Co.