Introduction Arterial blood gas (ABG) analysis is commonly used to monitor patients with acute respiratory problems but can be painful and associated with potentially serious side-effects. Recently there has been renewed interest in non-arterial forms of blood gas analysis with a suggestion that such techniques could replace >60% of ABGs.¹ It is however difficult to quantify the impact that non-ABG sampling could have as there is little published data on the clinical burden that ABGs represent. We were interested in establishing how many ABGs are routinely done in a real world setting.

Methods We retrospectively analysed acute admissions (all cause) to a ward based level 2 Respiratory Emergency Care Unit (RECU) at a University Teaching Hospital over a 6 month period. Prospectively we analysed visual analogue pain scores (VAS) and complications including attempt rates.

Results Over a 6month period (Apr-Oct) 57 of 111 patients admitted to the RECU had complete datasets. A total of 432 ABGs were obtained from this cohort giving an average of 7.6 ABGs (range 2 – 22) per patient per admission and on average patients had 2.3 ABGs each day whilst on RECU.

Overall the mean number of attempts per ABG of the prospectively collected cohort (n = 100) was 1.6 (range 1 – 8; 44% physician obtained). Taking this into account a patient could therefore expect to be stabbed 3.7 times every day or 11 times in total during their admission through the RECU. The most commonly documented complication amongst our patients was pain but average pain scores were relatively low in keeping with other published data (median VAS = 3, IQR 5); no serious complications were reported.

Conclusions Our data suggests that patients requiring admission to a level 2 respiratory unit experience a high burden of ABG testing during their stay. Using published literature on the potential impact of Non-ABG sampling our data suggests that >500 ABGs could be avoided each year on our acute respiratory unit alone.

Reference

1. McKeever T, Hearson G, Housley G, et al. Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study. Thorax 2016;71(3):210–5.