Clinical guidance for unfractionated heparin dosing and monitoring in critically ill patients

ABSTRACT

Introduction

Unfractionated heparin is a widely used anticoagulant in critically ill patients. It has a well-established safety profile and remains an attractive option for clinicians due to its short half-life and reversibility. Heparin has a unique pharmacokinetic profile, which contributes to significant inter-patient and intra-patient variability in effect. The variability in anticoagulant effect combined with heparin’s short half-life mean close monitoring is required for clinical efficacy and preventing adverse effects. To optimize heparin use in critically ill patients, effective monitoring assays and dose adjustment strategies are needed.

Areas Covered

This paper explores the use of heparin as an anticoagulant and optimal approaches to monitoring in critically ill patients.

Expert opinion

Conventional monitoring assays for heparin dosing have significant limitations. Emerging data appear to favor using anti-Xa assay monitoring for heparin anticoagulation, which many centers have successfully adopted as the standard. The anti-Xa assay appears have important benefits relative to the aPTT for heparin monitoring in critically ill patients, and should be considered for broader use.

KEYWORDS:

• ACT
• anti-Xa
• aPTT
• critical illness
• heparin
• monitoring

Article highlights

• Despite the advent of novel anticoagulants, heparin remains a mainstay of therapy in critically ill patients.

• UFH displays large intrapatient and interpatient variability in effect, thus close monitoring is required.

• Critically ill patients are at increased risk of bleeding and thrombosis, as well as other biological factors that can affect heparin dosing and monitoring.

• The anti-Xa assay is emerging as a superior option compared with the aPTT, for measuring the effect of IV heparin in critically ill patients.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Acknowledgments

M. N. Samimi would like to acknowledge funding from the RBWH Foundation Postgraduate Scholarship. J.A. Roberts would like to acknowledge funding from the Australian National Health and Medical Research Council for a Centre of Research Excellence (APP2007007) and an Investigator Grant (APP2009736) as well as an Advancing Queensland Clinical Fellowship. J A Dhanani would like to acknowledge funding for a Metro North Clinician Researcher Fellowship and an Advancing Queensland Clinical Fellowship.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.