Evaluation of Fentanyl Transdermal Patch Absorption in Hemodynamically Unstable ICU Patients.

The fentanyl patch will be applied as per standard ICU protocol for pain management. Blood levels will be monitored every 4 hours for 48 hours. Patients in this group require norepinephrine (\>5 drops/hour of 4 mg/50 mL) to maintain MAP ≥ 65 mmHg.

The fentanyl patch will be applied as per standard ICU protocol for pain management. Blood levels will be monitored every 4 hours for 48 hours. Patients in this group maintain MAP ≥ 65 mmHg without norepinephrine infusion.