Final answer:
The nurse should hold the next dose of heparin and notify the healthcare provider because the aPTT is significantly elevated, indicating an increased risk of bleeding, while the INR is below the therapeutic range. Pharmacogenomics could aid in personalizing warfarin dosages.
Step-by-step explanation:
The administration of anticoagulants such as heparin and warfarin is critical in the treatment of conditions like pulmonary embolism. The activated partial thromboplastin time (aPTT) and the international normalized ratio (INR) are tests used to monitor the effectiveness of anticoagulant therapy. In this case, a heparin dose of 1,200 units/hr is being infused, and the patient is also on a 5 mg daily dose of warfarin.
Given that the client's aPTT is 98 seconds and the INR is 1.8, the best action would be to hold the next dose of heparin and notify the healthcare provider (option c). An aPTT of 98 seconds is higher than the usual therapeutic range, indicating an increased risk of bleeding. While the INR of 1.8 is below the usual therapeutic range (2-3 for most indications), the elevated aPTT takes precedence because of the immediate bleeding risk. Meanwhile, warfarin therapy adjustments, based on INR, should be carried out cautiously and guided by the healthcare provider's advice as it has a delayed effect.
Given the importance of dosage and individual patient response, pharmacogenomics can play a role in determining the appropriate doses of medications like warfarin, as genetic variations affect drug metabolism and response.