(1327) Evaluation of Low- Versus High-Dose Heparin Protocols for Continuous Renal Replacement Therapy

Introduction: In critically ill patients receiving continuous renal replacement therapy (CRRT), circuit clotting is the most frequent cause of therapy interruption. Regional citrate and unfractionated heparin (UFH) are commonly utilized to decrease clotting frequency. Limited data exists regarding the optimal UFH dosing regimen that maintains adequate circuit patency and extends filter lifespan while minimizing bleeding risk. This study aims to compare the efficacy of low-dose (LD) and high-dose (HD) heparin protocols in critically ill patients requiring CRRT at a large academic medical center.

Methods: This retrospective chart review included critically ill patients admitted to University of Utah Hospitals that received UFH while on CRRT between May 2014 and June 2023. Patients were stratified by LD (goal partial thromboplastin time (PTT) 40 to 60 seconds) or HD (goal PTT 70 to 90 seconds) protocols[KD1] . The primary outcome was CRRT filter lifespan prior to clotting. Secondary outcomes included duration of active CRRT, number of filter changes, transfusion requirements, ICU and hospital length of stay, and incidence of transition to regional citrate or alternative heparin protocol.

Results: A total of 204 patients were screened, with 62 patients meeting inclusion criteria, and 87 distinct heparin protocols utilized (LD=55, HD=32).  There was no difference in patient demographics, assigned by initial heparin protocol administered, including[KD2]  total duration of CRRT order. Filter lifespan was similar between groups (25 hours(h) for LD vs 28h for HD, p=0.77). There was a trend towards increased time actively receiving CRRT for patients on HD protocols vs LD protocols (99h vs. 83h, p=0.18) and fewer filter changes required for clotting per 48 hours in HD vs LD (0.00 vs 0.26, p = 0.06). There was no difference in secondary outcomes.

Conclusions: This study is the first to compare the efficacy of low-dose and high-dose heparin protocols for critically ill patients undergoing CRRT.  While this study was likely underpowered to detect a difference in filter lifespan, there was a trend towards increased time actively receiving CRRT and fewer filter changes in the HD heparin protocol group. Further investigation is warranted to confirm these findings.