///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Neuraxial analgesia after high dose unfractionated heparin

Abstract Number: RF1BA-213
Abstract Type: Case Report Case Series

Katharine Thompson MD1 ; Richard Smiley MD, PhD2

Introduction: Morbidity and mortality associated with deep venous thrombosis (DVT) and pulmonary embolism has become a more recognized problem in obstetrics; utilization of thromboprophylaxis and anti-coagulation has increased. Due to pharmacokinetic and pharmacodynamic effects in pregnancy, high doses of unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are often used near term. This can be challenging to anesthesia providers considering neuraxial procedures.

Case:A 38-year-old G2P0 with a history of lupus and anti-phospholipid syndrome complicated by prior DVT presented at 41wk gestation for induction of labor. Throughout the pregnancy, she had been managed with warfarin and transitioned to 15000 UFH q12h at 37 weeks gestation. On the day of her admission, she self-dosed heparin ~ 15 hours prior to anesthesia consultation for epidural analgesia, at a cervical dilation of 3 cm. No coagulation studies were available; the anesthesiologist recommended determining the aPTT. The aPTT was 40.6 seconds, approximately 17% above the lab’s upper limit of normal (34.5 sec). Given the elective nature of analgesia, it was recommended to wait 2-3 hours and recheck the aPTT. Approximately 150 minutes later, now 19 hours after the heparin dose, the aPTT was 35.3 seconds. Although just above the upper limit of normal, the decision was made to proceed with epidural placement. The procedure and her labor were uneventful.

Discussion:

Unlike LMWH, recommendations for management of patients on high-doses of UFH are unclear. For example, in the recent SOAP consensus statement (1) it is noted that in patients receiving > 10000U/dose or > 20000U daily there is “minimal data to guide risk assessment” and it is only after 24 hours have passed since dosing AND with a normal aPTT that it is assumed to be “likely low risk to proceed with neuraxial.” Despite the time since her last UFH dose being < 24hr, and acknowledging that the aPTT does not reveal everything about UFH effect, we decided that with an aPTT near normal limits and decreasing, reasonable assumptions could be made about elimination of UFH and a low risk of procedurally-related bleeding. While this is only one case, there are few if any other reports of actual coagulation test trends in pregnant women receiving high dose UFH at term. As anticoagulation in pregnant patients becomes more commonplace, further studies need to be aimed at determining more accurate UFH pharmacologic profiles, and how to assess complication risk in these patients (ex. aPTT, thromboelastography). Thromboelastography was not available to us, and its role in assessing UFH effect in this context is unclear. While it is recognized that earlier communication between the obstetric and anesthesia teams may have avoided this issue by delaying induction, we believe that determining the aPTT trend under the circumstances was a reasonable

method to assess whether to proceed.

1. Anesth Analg 2018;126:928-44

SOAP 2019