Arterial blood gas analysis: as safe as we think? A multicentre historical cohort study

Arterial punctures (APs) for arterial blood gas (ABG) analyses are much-used medical procedures. To date, no large studies have been conducted on the major complication rate of APs. We aimed to describe the risk of major complications within 7 days after puncture and investigate whether using antithrombotic medication affected this.

We included all APs performed for ABG analysis at three Danish hospitals from January 1, 1993 to February 25, 2013. We excluded APs ordered by the anaesthesiology department, intensive care unit (ICU) or in patients <18 years old. Data on the patient level were extracted from the Danish National Patient Registry, Danish Civil Registration System and Odense Pharmaco-Epidemiologic Database (OPED), the latter providing us with information on antithrombotic medication. Initially, two clinicians compiled a list with all procedures and diagnoses that could possibly be a consequence of APs. The selected procedures and diagnoses were further categorised independently by three surgeons and used to indicate the complication rate.

We analysed 473 327 APs and found 669 (0.14%, 95% CI 0.13-0.15) APs led to major complications: embolisms or thrombosis (49.0%), aneurysms (15.4%), nerve damage (1.5%), arteriovenous fistulas (0.6%) or of another kind (33.5%). The identified major complication rates in patients on antithrombotic medication were increased (OR 1.31, 95% CI 1.07-1.61).

APs for ABG analyses are safe procedures. The major complication rate within 7 days was 0.14% (95% CI 0.13-0.15). Patients on antithrombotic medication carry an increased risk of developing major complications.