A nurse is caring for a client prescribed Heparin. Which nursing action is most appropriate regarding monitoring aPTT levels and preparing protamine sulfate as an antidote?

• 1 The nurse plans to draw the trough specimen just prior to initiating the very first dose of vancomycin, because a baseline drug level is necessary to calculate the initial dose and to predict the peak concentration that will be achieved after infusion.
• 2 About 30 minutes before the next scheduled dose (typically before the fourth dose) to allow steady state and reflect the lowest serum concentration; goal trough is 15 to 20 mg/L for serious MRSA infections, with AUC-guided dosing increasingly preferred per current guidelines.
• 3 The nurse plans to draw the trough specimen 30 minutes before the second scheduled dose, believing that after the first dose, the drug has reached adequate therapeutic levels and a blood draw just before the next dose reflects the lowest concentration needed for monitoring. ✓ Correct answer
• 4 The nurse plans to draw the trough specimen 60 minutes after the completion of the third dose, because this timing reflects the peak concentration when the drug is at its highest level and is the standard for vancomycin therapeutic monitoring.

For study reference only. Always follow current clinical guidelines and your institution’s protocols.