Prophylactic granisetron for post-spinal anesthesia shivering in cesarean section: A randomized controlled clinical study.

Background: The serotonergic system is known to be involved in control of post-anesthetic shivering. Our hypothesis was that prophylactic granisetrone (serotonin antagonist) might reduce incidence of post-spinal anesthesia shivering in cesarean section.
Methods: Parturient scheduled for elective cesarean delivery under spinal anesthesia were allocated to receive 0.9% saline (Group I, n = 71), 1 mg granisetron (Group II, n = 69), or 0.7 mg granisetron (Group III, n = 72) before the spinal block. Assessment parameters included; hemodynamics, tympanic membrane temperature, neonatal Apgar score, shivering score, patient satisfaction scores about shivering prophylaxis and adverse effects.
Results: Clinically significant shivering was recorded in 55/71 patients (77.5%) in group I, 11/69 (15.9%) in group II and 21/72 (29.2%) in group III (P = 0.000). The intensity of shivering was significantly lower in patients who received granisetron 1 mg compared with granisetron 0.7 mg or saline (P = 0.000). Patients who received prophylactic granisetron 1 mg reported lower mean intraoperative arterial pressure and heart rate values and consumed higher doses of iv ephedrine compared with 0.7 mg granisetron or saline placebo (P < 0.05). Pruritus significantly decreased from (22.5%) in control group to (0%) in granisetron groups (P = 0.000). Nausea was reported in 8 vs 10 and four in group I, II and III, respectively (P < 0.03). Sixteen vs eight and six patients vomited in group I, II, and III, respectively (P < 0.03). Higher patient satisfaction scores were recorded in group II (9.83 ± 0.29, P < 0.03) and III (9.14 ± 1.04, P < 0.04), compared with control group (8.23 ± 1.14).
Conclusion: Prophylactic granisetron effectively reduced incidence and severity of perioperative shivering in a dose dependent manner, compared to placebo controls.
(© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)