To ABG or Not to ABG-Reducing Inappropriate Arterial Blood Gas Testing in Critical Care

Arterial blood gas (ABG) testing is a common investigation in critical care; however, evidence suggests that 33%-66% of samples may be taken without a clear clinical indication. Unnecessary testing increases costs, contributes to iatrogenic anaemia and wastes staff time. It also carries an environmental burden through resource use, waste generation and associated carbon emissions.

To evaluate the impact of an education- and guideline-based intervention on reducing clinically inappropriate ABG testing in a UK Intensive Care Unit (ICU) and to perform a triple bottom line assessment.

A pre- and post-quality improvement project in a 23-bed level III ICU. Baseline audit data were collected on ABG indications and appropriateness. A locally developed ABG guideline was introduced, supported by targeted bedside teaching and reinforced through visible prompts. Post-intervention audit mirrored baseline methods. This quality improvement project was underpinned by the Sustainability in Quality Improvement (SusQI) framework, which integrates environmental, financial and social sustainability principles into traditional plan, do, study and act (PDSA) methodology.

The total number of ABG tests decreased from 7348 to 4819, representing a 34.4% reduction. The mean ABGs per patient decreased from 14.27 to 11.78 (rate ratio, 0.826; 95% CI, 0.796-0.856; p < 0.001). The proportion of inappropriate ABGs declined from 27.0% to 4.1% (absolute risk reduction 22.9%, NNT = 4.4, p < 0.001). Post-intervention savings included £2781.90 in direct costs, 210.8 h of clinician time, 1.396 L of patient blood and 124.0 kg CO₂e emissions. No adverse impact on patient care was identified.

A low-cost, nurse-engaged intervention reduced unnecessary ABG testing without compromising safety, delivering quantifiable financial, operational and environmental benefits. Incorporating sustainability metrics strengthens the case for change and aligns with the NHS Net Zero agenda.

Critical care nurses play a central role in ABG stewardship. Equipping them with clear guidelines, education and visible prompts can rapidly change practice, improving patient safety, reducing waste and supporting sustainable healthcare delivery.