Antinociceptive effect of perioperative adenosine infusion in abdominal hysterectomy

Background: Adenosine (ADO), and stable analogs thereof, have been shown to exert antinociceptive action in cutaneous and deep somatic pain under experimental and clinical conditions in animals and in humans. The aims of this randomized double-blind placebo-controlled study were to evaluate if a low dose of intravenous (i.v.) ADO could reduce the requirements of volatile anesthetic and postoperative opioid in connection to hysterectomy, where visceral nociception significantly contributes to pain.
Methods:
Forty-three women, age 32–65 years, ASA I and 11, scheduled for abdominal hysterectomy, were assigned to receive an i.v. infusion of either adenosine, 80 μg. kg^-1 min^-1, or placebo during surgery. Anesthesia was maintained with isoflurane (ISO)/N₂O/ O₂ inhalation. Postoperatively, a reduced dose of 40 μg. kg^-1. min^-1 was continued for 3 h.
Results: The end-tidal (ET-) IS0 was equal between groups before surgery. During surgery, the IS0 requirement was increased, compared to the preoperative level, in the placebo group, while the requirement declined in the ADO group. The overall IS0 requirement in the ADO group was reduced by 36% (P<0.002). The first 24 h postoperative opioid requirement, with equal resting pain in both groups, was 18% ( P < 0.05)lower in the ADO group.
Conclusion: A low dose of perioperative adenosine infusion in abdominal hysterectomy reduces the requirements of volatile anesthetic and postoperative opioid analgesic.