Assessing the Feasibility of Adequate Anticoagulation With Unfractionated Heparin When Administered based on Lean Body Weight in Adult Patients Undergoing Open Heart Surgeries - A Prospective Cohort Study

Abstract

Objectives: Weight-based unfractionated heparin (UFH) dosing before cardiopulmonary bypass (CPB) may overestimate requirements in patients with lesser lean body weight. We evaluated the feasibility of lean body weight (LBW)-based heparin dosing to achieve a target activated clotting time (ACT) before CPB in Indian adults undergoing elective on-pump cardiac surgery. Material and Methods: In this single-centre prospective observational study, 81 adults aged 18–70 years undergoing elective on-pump cardiac surgery received intravenous heparin 300 IU/kg LBW. ACT was measured 3 minutes later. Patients with ACT <480 s received protocol-guided escalation to 350 and then 400 IU/kg LBW. Patients who remained below target after 400 IU/kg LBW received 400 IU/kg actual body weight (ABW). Results: After 300 IU/kg LBW, 63/81 patients (77.8%; 95% confidence interval [CI], 68.8–86.8) achieved an ACT ≥480 s. A further 15 (18.5%; 95% CI, 10.0–27.0) achieved target ACT after 350 IU/kg LBW, and 2 (2.5%; 95% CI, 0.3–8.7) after 400 IU/kg LBW. One patient (1.2%; 95% CI, 0.03–6.7) required 400 IU/kg ABW. Thus, 80/81 patients (98.8%) achieved target ACT using the LBW-based escalation protocol. No participant met the study definition of heparin resistance. Conclusion: A LBW-based, stepwise heparin protocol achieved target ACT before CPB in almost all participants and was feasible in this cohort. Comparative studies incorporating heparin concentration monitoring and clinical bleeding outcomes are needed before routine adoption.