A client with unstable angina and chronic kidney disease is receiving a continuous infusion of unfractionated heparin. Which value for activated partial thromboplastin time (aPTT) would indicate to the nurse that the heparin therapy is at an optimal therapeutic level?

Unfractionated heparin is used as an anticoagulant in unstable angina. It prevents the conversion of fibrinogen to fibrin and prothrombin to thrombin, both components of clot formation. The aPTT is a laboratory test that characterizes blood coagulation. It is used to monitor treatment effects of clients receiving heparin. The normal aPTT is 25–35 seconds. Heparin infusions are titrated to obtain a therapeutic value of aPTT, typically 1.5–2 times the normal value. Therapeutic value for aPTT is 46–70 seconds. The nurse would evaluate the aPTT for a therapeutic value and make adjustments in the rate of infusion of the heparin as needed. (Options 1 and 2) These are normal aPTT levels for clients not being anticoagulated. (Option 4) This aPTT is too high. This client is at risk for bleeding. The heparin should be titrated down based on the heparin drip protocol. Educational objective: The nurse caring for a client receiving a heparin infusion should monitor the aPTT and follow the heparin infusion protocol for titration. A therapeutic level is 1.5–2 times normal, or an aPTT of 46–70 seconds. Pharmacological and Parenteral Therapies NCSBN Client Need