Comparing the Effect of Adding Fentanyl, Sufentanil, and Placebo with Intrathecal Bupivacaine on Duration of Analgesia and Complications of Spinal Anesthesia in Patients Undergoing Cesarean Section

Spinal anesthesia is the method of choice for most elective and emergency Cesarean sections. To increase the duration of anesthesia and improve the quality of analgesia during and after surgery, intrathecal opioids, as adjuvant drugs, are used in combination with local anesthetics.
This was a double-blind clinical trial performed on 99 patients. Women were divided into 3 groups of fentanyl, sufentanil, and placebo. For fentanyl group, 12.5 mg of bupivacaine and 25 micrograms of fentanyl; for sufentanil group, 12.5 mg of bupivacaine and 2.5 micrograms of sufentanil; and for placebo group, 12.5 mg of bupivacaine and a half mL of normal saline were injected in subarachnoid space. The sensory and motor block, hemodynamic status (mean blood pressure and heart rate), and probable complications were assessed.
There was no significant difference between the groups in demographic characteristics. Durations of analgesia were, respectively, 314 ± 42.95, 312.5 ± 34.44, and 116.1 ± 42.24 minutes in the fentanyl, sufentanil, and placebo groups (P = 0.0001). Duration of sensory and motor block was higher in fentanyl and sufentanil groups compared with the placebo group. The highest duration of sensory and motor block was noted in sufentanil group (P = 0.0001). No significant difference was found between the groups in the hemodynamic parameters (P > 0.05). The frequency of itching in the fentanyl group was higher than sufentanil and placebo groups (P = 0.003). Also, shivering was higher in the placebo group compared with other groups (P = 0.036).
According to the results, adding 25 microgram fentanyl or 2.5 microgram sufentanil to intrathecal bupivacaine increased the duration of analgesia and provided hemodynamic stability with no major complication. As administering intrathecal fentanyl had a similar duration of analgesia like sufentanil with faster return of motor block and ambulation, it seems that it is a preferred additive for Cesarean section surgery.