# A 60-year-old on a weight-based IV heparin drip for acute pulmonary embolism has serial aPTT results per hospital protocol (target therapeutic range aPTT 60-90 seconds). Review the trend and answer the questions.

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> language: en  
> subject: Pharmacological and Parenteral Therapies  
> category: PPT

## Question

A 60-year-old on a weight-based IV heparin drip for acute pulmonary embolism has serial aPTT results per hospital protocol (target therapeutic range aPTT 60-90 seconds). Review the trend and answer the questions.

| Time | Data |
| --- | --- |
| 00:00 baseline | aPTT 32 sec (subtherapeutic). Heparin started at 18 units/kg/hr after 80 units/kg bolus. |
| 06:00 | aPTT 58 sec (just below target). Rate increased per protocol to 20 units/kg/hr. |
| 12:00 | aPTT 78 sec (therapeutic). No bleeding noted. Rate continued at 20 units/kg/hr. |
| 18:00 | aPTT 142 sec (supratherapeutic). Patient reports gum oozing with toothbrushing; no other bleeding. |

Q1. What is the aPTT trend?

Subtherapeutic — increase rate
Stable therapeutic — continue current rate
Supratherapeutic but no bleeding risk — continue and reassess
Supratherapeutic with early bleeding signs — risk of hemorrhage

Q2. What is the priority nursing action at 18:00?

Increase the rate to drive aPTT up further
Continue infusion and obtain a STAT INR
Hold the infusion for 1 hour, resume at a reduced rate per protocol, recheck aPTT in 6 hours, and assess for active bleeding
Discontinue heparin permanently and consult hematology

## Explanation

At 18:00 the aPTT is 142 seconds — supratherapeutic (> 90), placing the patient at significant bleeding risk. Per standard heparin protocols, the nurse HOLDS the infusion for 1 hour, then RESUMES at a reduced rate (typically 3 units/kg/hr lower) and rechecks aPTT in 6 hours. The nurse also assesses for active bleeding (gums, urine, stool, wound site, neuro changes for ICH), and notifies the provider. Increasing the rate (1) or simply continuing (3) is dangerous; obtaining a STAT INR (4) is clinically irrelevant — heparin is monitored by aPTT, not INR.

## In-depth explanation

The single most-tested heparin titration scenario is the supratherapeutic aPTT. The standard response is HOLD-REDUCE-RECHECK with bleeding assessment. Memorize: aPTT therapeutic = 1.5 to 2.5 times control (commonly 60-90 seconds). For severe overshoot or active bleeding, protamine sulfate is the antidote (1 mg per 100 units of heparin given in the last 4 hours, not exceeding 50 mg).

## Clinical scenario

**60-year-old on weight-based IV heparin drip** for **acute submassive pulmonary embolism**. Hospital protocol target **aPTT 60-90 seconds**. Q6H aPTT draws with nurse-driven titration per protocol.

## Key concepts

- **aPTT therapeutic range (heparin)** — Target 1.5-2.5 times control, commonly 60-90 seconds depending on hospital reagent and protocol.
- **Heparin protocol HOLD-REDUCE** — Standard response to supratherapeutic aPTT: hold infusion, reduce rate, recheck in 6 hours, assess for bleeding.
- **Protamine sulfate** — Heparin antidote for severe overshoot or active bleeding; 1 mg per 100 units heparin given in the prior 4 hours, max 50 mg per dose.

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