Heparin Holly — Heparin: aPTT, Protamine Sulfate & HIT
The heparin drip keeps her clot from growing — but the aPTT tells the nurse how fast it runs, and protamine turns it off
Holly's heparin drip has run for two days for her DVT. This morning her aPTT is 110 seconds (control 30), she has oozing at her IV site, and her platelet count has fallen by half since admission.
Holly has a deep vein thrombosis and a heparin infusion keeping her blood thin. Heparin activates antithrombin to shut down clotting factors within minutes — which is why it is given IV for acute clots and monitored with the aPTT, targeting roughly 1.5-2.5 times the control value. Too little and the clot grows; too much and she bleeds. The antidote is protamine sulfate, given slowly IV. The hidden danger is heparin-induced thrombocytopenia (HIT) — an immune reaction where platelets paradoxically plummet and new clots form — so platelet counts are watched as closely as the aPTT. Compare and contrast: warfarin is monitored by INR and reversed with vitamin K; heparin is aPTT and protamine.
Read Heparin Holly's full story →The story arc
The setup
Holly is diagnosed with a DVT and started on a weight-based heparin infusion with aPTT checks every 6 hours to guide the rate.
The turn
Holly's aPTT climbs to 110 seconds against a control of 30, and her gums bleed when she brushes her teeth.
The crisis
Her platelet count drops from 240,000 to 95,000 and a new clot is suspected in her other leg despite the heparin.
The save
The heparin is stopped, protamine sulfate is prepared for the over-anticoagulation, a non-heparin anticoagulant replaces the drip for HIT, and heparin is flagged as an allergy.
NCLEX study section — Heparin: aPTT, Protamine Sulfate & HIT
What this chapter is testing: the recognition cues, the numbers and the priority action.
Study section: Pharmacology
Take this chapter into practice questions on the same topic.