Effect of Addition of Various Doses of Fentanyl Intrathecally to 0.5% Hyperbaric Bupivacaine on Perioperative Analgesia and Subarachnoid-Block Characteristics in Lower Abdominal Surgery: A Dose-Response Study

The data suggest that in a nonobstetric population receiving spinal anesthetic for superficial lower abdominal surgery (hernia repair), addition of 10 μg fentanyl to bupivacaine 0.5% (hyperbaric) significantly improves the quality and duration of analgesia. No further advantage occurs if the dose of fentanyl is increased up to 40 μg.