Resident University of Toronto Etobicoke, Ontario, Canada
Background: The Heart Function Clinic at Toronto General Hospital serves more than 5000 patients annually, offering rapid assessment, blood work, and administration of intravenous (IV) medications. Point of care testing (POCT) for venous blood gases (VBG) enables faster turnaround. However, its clinical utility in the outpatient setting remains unexplored. This study sought to evaluate the clinical and operational impact of VBG POCT implementation, specifically assessing time to medication changes, time to clinical disposition, and need for potassium supplementation during IV furosemide administration.
METHODS AND RESULTS: All patients undergoing VBG POCT at the Toronto General Hospital Heart Function Clinic from March 2025 onwards were included. Each clinic visit was analyzed. Data measured included baseline demographics, VBG measures including lactate and potassium, medication changes, patient disposition, and time taken to make clinical decisions. VBG values were compared to central lab values for quality control. Continuous variables were presented as mean ± standard error of the mean. Categorical variables were presented as counts/percentages of the cohort. Statistical significance was set at p ≤ 0.05. This was approved by the Quality Improvement Review Committee, as it was considered quality improvement work.
57 unique visits were included and 37.5% of the cohort were female. The most common etiology of their heart failure was non-ischemic cardiomyopathy (73%). The leading indication for VBG POCT was guideline-directed medical therapy (GDMT) uptitration (44.1%) (Table 1). 43 visits resulted in a medication change following the VBG POCT including providing IV furosemide for one dose (30.5% of visits) or a mineralocorticoid receptor antagonist (MRA) increase (22%). Potassium supplementation was administered in 33% of cases during IV furosemide use, guided by VBG potassium levels. For those that had an MRA started, the average potassium was 4.0 ± 0.15 mmol/L relative to 4.2 ± 0.07 mmol/L in those who it was not (p = 0.18). Of those who had monitoring lactate as an indication (13 total), 46% were admitted to hospital with a lactate range of 1.4-5.3 mmol/L. In total, 56% of visits had a decision about disposition or medication changes within one hour of the VBG POCT, with an average time of 56 ± 5.7 minutes.
Conclusion: The implementation of VBG POCT in the Heart Function Clinic enabled rapid clinical decision-making, including timely GDMT optimization using accurate potassium levels and appropriate triage of acutely unwell patients, with an average time of under one hour. These findings support the broader adoption of POCT in high-volume heart failure clinics.
