Selecting heparin doses based on weight has been found to provide Partial Thromboplastin Time (PTT) results that are more likely to be within the desired therapeutic range and to fluctuate less when doses are adjusted. A protocol can help clinical personnel quickly and accurately select the appropriate dosage based on the patient’s weight and PTT values. Nurses and pharmacists can initiate and manage these protocols, saving time for both them and physicians. A weight-based heparin protocol also helps provide timely adjustments to dosages, which in turn helps to decrease the risk of adverse drug events.
Tips
- Round off doses to reasonable numbers that staff can work with — for example, do not select a dose of 1273.6 units/ hour.
- Include both the loading dose and subsequent bolus doses in the protocol.
- Consider capping the weight value used in dosing at 100 kilograms when treating obese patients, to avoid an adverse drug event.
- Develop a different weight-based protocol for patients receiving thrombolytics or G2b/3A inhibitors, whose heparin doses will need to be lower.
- Watch out for "tail chasing," the phenomenon in which the PTT is low, so the dose is raised, but then the PTT is high, so the dose is lowered to where it was before and then the PTT gets low again. The protocol needs sufficient flexibility to accommodate such reactions.
- Limit to no more than one or two protocols.
