Dose Response Study of Intrathecal Fentanyl Added to Bupivacaine in Patients Undergoing Elective Caesarean Section in Spinal Anesthesia

Thumbnail Image
Yahya, Ahed
Journal Title
Journal ISSN
Volume Title
An-Najah National University
Background Applying spinal anesthesia for caesarean sections associated with a certain side effect such as hypotension caused by the dose of hyperbaric bupivacaine, additives of potent opioid such as fentanyl may reduce the dose of toxic local anesthesia which will be more hemodynamic stability and also enhance of adequate analgesia. Aims This study conducted in order to evaluate the side effects of four spinal solutions in purpose of finding best possible combinations of fentanyl and bupivacaine, comparing the efficiency and safety of this combinations by using different doses of fentanyl in spinal anesthesia in cesarean section, and assessing the side effects, duration of analgesia, hemodynamic parameters and neonatal outcomes by using an Apgar score. Methods One hundred sixty Patients randomized into four groups 40 of each : Group-I (F10): received 1.5ml (7.5mg) of 0.5% Bupivacaine heavy & 10μg Fentanyl .Group-II (F15): received 1.5ml (7.5mg) of 0.5% Bupivacaine heavy & 15μg Fentanyl .Group-III (F25): received 1.5ml (7.5mg) of 0.5% Bupivacaine heavy & 25μg Fentanyl and (control group ). Group-IV (B10): received 2 ml (10mg) of 0.5% Bupivacaine heavy and saline containing no fentanyl. Side effects such as: nausea, vomiting, bradycardia, hypotension episodes, headache, pruritis, shivering, drowsiness, restlessness, dizziness, sedation, patients’ satisfaction, analgesic requirements and duration of effective analgesia were evaluated. Moreover, onset and duration of sensory and motor block were measured. Results Similar distribution of age, height, weight and duration of surgery as evidenced by statistical analysis, The results show that there was significant differences at the level (p ≤ 0.05) in comparison between B10 only and Fentanyl 10mcg, Fentanyl 15mcg and Fentanyl 25mcg related to the onset of sensory blockade to T10 and T6 and indicate fentanyl 25 mcg more fast onset of sensory block. Onset of motor block was earlier in bupivacaine 10 mg group in comparison with other three groups, which is statistically significant difference. According to bradycardia, there were no significant differences between groups. Hypotension episodes in bupivacaine 10mg more common mean (3.12), which is statistically significant difference when compared to other three groups. Incidence of headache was decreased in fentanyl groups in comparison with B10 group but there were no significant differences between the groups. There were significant differences regarding the incidence of pruritis in fentanyl 25 mcg (9/40) and fentanyl 15 mcg (6/40) groups when compared to B10. Nausea and vomiting were observed in B10 group while decreased significantly in other three groups. According to Restlessness, sedation and respiratory depression, there were no significant differences between all groups. There were no significant differences in Apgar scores at 1 and 5 min. The duration of sensory block was prolonged significantly in fentanyl groups. Duration of motor blocked was decreased significantly with decrease Bupivacaine dose and early motor recovery was observed significantly in fentanyl groups compared to B10 group. Duration of effective analgesia increased as increased fentanyl dose which was statistically significant difference in all fentanyl groups compared to B10 group. Regarding to postoperative analgesic needed, significant differences were found in all fentanyl groups in comparison to control group, fentanyl 25 mcg more significant and less rescue analgesic requirements in post-operative period by mean (1.85 ) followed by fentanyl 15 ( 2.3) mcg then B10 (2.37) and fourthly fentanyl 10 mcg (2.42 ) . Conclusion Addition of Fentanyl was effective with minimal side effects; also it improves the quality of anesthesia, prolongs the duration of sensory block, faster onset of sensory block and significantly reduces post-operative rescue analgesic needed, also better hemodynamic stability. Where 0.5% bupivacaine 10 mg alone faster of onset of motor blocked and prolonged of duration of motor blocked. Finally we conclude and recommend of best combination in spinal anesthesia for elective cesarean section is fentanyl 25 mcg with 0.5% bupivacaine 7.5 mg because it was superior in duration of effective analgesia and less post-operative rescue analgesic needed also more patients’ satisfaction, however may have less side effect in fentanyl 10 mcg and 15 mcg groups. In conclusion fentanyl 25 mcg with 0.5% bupivacaine 7.5 mg is more favorable.
Intrathecal fentanyl , bupivacaine , spinal anesthesia , cesarean section