2026 Southeastern Residency Conference

ASSESSMENT OF ADHERENCE TO AN INSTITUTIONAL aPTT LEVEL MONITORING PROTOCOL FOR UNFRACTIONATED HEPARIN INFUSIONS
George Saied, Rachel Hemberger, Mary Beth Brinkman
TriStar Centennial Medical Center – Nashville, TN
Background: The use of continuous infusion unfractionated heparin (UFH) is common for treatment and prophylaxis of venous thromboembolism (VTE), myocardial infarctions (MI), anticoagulant bridging, and is used second line in several other disease states. UFH has been labeled a “High-Risk Medication” since the early 2000s and has severe adverse effects associated with bleeding and platelet abnormalities. The use of UFH requires close monitoring of laboratory findings, specifically the use of Activated Partial Thromboplastin Time (aPTT), to ensure patient safety and medication efficacy. Supratherapeutic aPTT levels result in increased bleeding risk while subtherapeutic aPTT levels result in increased clotting risk. Due to the frequency of aPTT monitoring, there is potential for delays in blood collection and necessary dose adjustments, thus increasing the risk of patient-safety events. Additionally, there is also potential for aPPT protocol recommendation to be misinterpreted or for the dose to be titrated inappropriately, thus leading to patient-safety events. This study seeks to evaluate adherence to our heparin protocol and identify specific areas for process improvement.

Methods: This was an Institutional Review Board-approved, single-center, retrospective cohort study of adult patients (≥18 years) who received a continuous heparin infusion at TriStar Centennial Medical Center from March 22, 2025 through March 31, 2025. The primary endpoint was adherence to the institutional UFH nursing protocol, defined as appropriate heparin bolus administration, dose titration, and timely aPTT ordering per protocol recommendation. Secondary endpoints included reasons for protocol nonadherence, percentage of aPTT values within the goal therapeutic range, time to achieve therapeutic range, and incidence of bleeding and thrombosis. Drips were followed for the first 72 hours after initiation. Descriptive statistics were used for data analysis.

Results: A total of 59 patients were included (Cardiac Serv, n = 36; DVT/PE, n = 23). The primary outcome of full protocol adherence was achieved in only 7 of 59 patients (11.9%). The most common drivers of non-adherence was incorrect initial drip rate and inappropriate dose titration. The mean percentage of aPTT values within the therapeutic range was 43.6%. Patients who experienced an adverse drug reaction (n=9, 15.3%) had a lower mean percentage of aPTT values in goal compared to those without an ADR (28.6% vs. 46.3%; p=0.056). Time to first therapeutic aPTT was significantly longer in the Cardiac Serv cohort compared to the DVT/PE cohort (0.87 days vs. 0.42 days; p = 0.001). Bleeding events occurred in 6 (10.2%) patients (Cardiac Serv 5.6% vs. DVT/PE 17.4%; p = 0.196) and thrombotic events in 7 (11.9%) patients (Cardiac Serv 8.3% vs. DVT/PE 17.4%; p=0.414). No statistically significant difference in adverse events was identified between cohorts, but trends do support increased risk in DVT/PE versus Cardiac Serv protocols.

Conclusions: Protocol adherence to institutional UFH aPTT monitoring was below goal, with fewer than 1 in 8 patients receiving fully adherent care. Non-adherence was primarily driven by incorrect initial rates and incorrect dose titration. Patients who experienced an ADR spent significantly less time within the therapeutic range, which highlights the clinical consequences of protocol deviations. The Cardiac Serv cohort took a longer time to reach first therapeutic aPTT compared to the DVT/PE cohort. These findings show clear opportunities for targeted nursing education, protocol clarification, and system-level process improvements to optimize UFH therapy and enhance patient safety.

 This research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.