Official Journals By StatPerson Publication
Table of Content - Volume 12 Issue 2 -November 2019
. Comparison of antiemetic efficacy of intrathecal fentanyl and dexmedetomidine for caesarean section in subarchnoid block
S K Adil Hasan1*, Manohar2
1Assistant Professor, 2Professor and HOD, Department of Anaesthesiology, Kamineni Institutes of Medical Sciences, Narketpally Nalgonda, Telangana, INDIA. Email: drsgsomani@gmail.com
Abstract Objective: To compare antiemetic efficacy of fentanyl and Dexmedetomidine as adjuvant to bupivacaine for preventing nausea-vomiting in women undergoing caesarean section under subarchnoid block. Study Design: Prospective randomized, double-blinded, placebo-controlled study. Materials and Methods: In present study 150 patients posted for elective caesarean section were included. After thorough pre-anaesthetic evaluation, patients were randomly divided into three groups using computer generated randomization technique. Group C: patients received 2 ml of hyperbaric bupivacaine (0.5%) + 0.5 ml of normal saline intrathecally (n=50). Group D: patients received 2 ml of hyperbaric bupivacaine (0.5%) + 5µg of Dexmedetomidine intrathecally (n=50).Group F: patients received 2 ml of hyperbaric bupivacaine (0.5%) + 12.5 μg of fentanyl intrathecally (n=50). Hemodynamic parameters, intraoperative and postoperative emetic episodes were assessed using Belville's score. Perioperative complication like hypotension, sedation, shivering and pruritis were recorded. All data was expressed as Mean ± Standard deviation (SD). Statistically analysis was done by using student’s unpaired t-test and ANOVA. p-value <0.05 was considered significant. Results: Demographic profile was comparable in all three groups. In the intraoperative and post-delivery period, an emesis free episode occurred in 31 of 50 patients (62%), 24 of 50 patients (48%) and 13 of 50 patients (26%) who had received IT Dexmedetomidine, IT fentanyl or IT placebo respectively. Among Dexmedetomidine and fentanyl groups, retching, nausea and vomiting was less in Dexmedetomidine group than fentanyl group; however, that did not differ significantly (p-value>0.05).Intraoperative rescue antiemetic was required in 7(14%) patients in the control group, however, the requirement was reduced to 3 (6%) in the midazolam group and 2 (4%) patient in Dexmedetomidine group. shivering was mainly seen in control group and pruritis in fentanyl group and bradycardia in Dexmedetomidine group. Conclusion:. From present study it is concluded that, co-administration of intrathecal fentanyl 12.5 μg or intrathecal midazolam 2.5 mg with 0.5% hyperbaric bupivacaine in the subarachnoid block significantly reduces intraoperative and postoperative nausea-vomiting in cesarean sections. Key Words: Bupivacaine, Caesarean section, Fentanyl, Dexmedetomidine, Subarachnoid block.
INTRODUCTION Nausea and vomiting intraoperatively and in early postoperative period during caesarean delivery under subarchnoid block is a common distressing symptoms.1 Emetic symptoms more frequently occur in the parturient because of high progesterone levels, which decreases gastrointestinal motility, reduces lower esophageal sphincter tone and increases gastrin secretion.2 These symptoms are reduced by several antiemetic drugs (like metoclopromide, domperidon, ondensatron etc), but none have been proved to be effective without significant adverse effects or high cost 3. The causes of nausea and vomiting are multifactorial and can largely be divided as patient risk factors, anesthetic technique and surgical procedure. Intrathecal (IT) administration of lipophilic Opioids such as fentanyl4 and Dexmedetomidine 5 have been reported to minimize the incidence of intraoperative and early postoperative nausea and vomiting in caesarean delivery under subarchnoid block. Fentanyl, is a synthetic μ opioid receptor agonist. It is preferred as an adjuvant in subarchnoid block because of its rapid onset and short duration of action. It increases both the duration and intensity of spinal anesthesia and decreases the intraoperative nausea and vomiting without having any deleterious effects on the neonate or mothers 6,7Dexmedetomidine is a specific and selective alpha 2 adrenoceptor agonist. Activation of receptors in the brain and spinal cord inhibits neuronal firing and leads to sympatholytic effect, causing hypotension, bradycardia, sedation and analgesia 8. Therefore, present study was conducted to compare antiemetic efficacy of fentanyl and Dexmedetomidine as adjuvant with bupivacaine for preventing nausea-vomiting in women undergoing caesarean section under subarchnoid block.
Material and Methods After approval from institutional ethical committee, present prospective randomized, double-blinded, placebo-controlled study was conducted in Department of Anaesthesiology, Kamineni Institute of medical sciences, Narketpally. Nalgonda, during February 2016 to May 2017 in 150 patients posted for elective caesarean section. Inclusion Criteria:
Exclusion Criteria:
After a thorough pre-anaesthetic evaluation of all patients, a written and informed consent was obtained, both for conduct of study as well as administration of subarchnoid block. They were kept nil by mouth for eight hours before surgery. Intravenous access was established with a 18G intravenous canula and preloading was done with 15 ml/kg Ringer Lactated solution. Anaesthesia machine, accessories, monitors and drugs were checked. Sample size was calculated using Open Epi, Version 3, open source calculator – SS mean on internet with confidence interval of 99%, power of 95% and ratio of two groups at 1:1; which was minimum 36 participants per group. All patients were randomly divided into three groups using computer generated randomization technique. Under all strict aseptic precautions, in lateral position, subarachnoid block was performed at L3-L4 intervertebral space with a 25G spinal needle. •Group C: patients received 2 ml of hyperbaric bupivacaine(0.5%)+0.5 ml of normal saline (n=50) •Group D:patients received 2 ml of hyperbaric bupivacaine (0.5%) + 5 μg of Dexmedetomidine (n=50). •Group F: patients received 2 ml of hyperbaric bupivacaine (0.5%) + 12.5 μg of fentanyl (n=50).
Following parameters were recorded: Hemodynamic parameters like heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure at 2 minute intervals for 10 minutes, then at 5 minute intervals for next 30 minutes and at 15 minute intervals till 2 hours after giving study drug. ECG and SpO2 monitored continuously. Intraoperative and postoperative emetic episodes were assessed using to the Belville's score 9 .Grade 0 - No nausea, Grade 1- Nausea, Grade 2- Retching Grade 3- Vomiting.at 30 min,1 hours, 2 hours, 4 hours, 6 hours, 12 hours and 24 hours .These emetic episodes were recorded by direct questioning by an anaesthesiologist blinded to study drug the patients have received. Nausea was defined as a subjectively unpleasant sensation associated with awareness of the urge to vomit; retching was defined as the laboured, spasmodic, rhythmic contractions of the respiratory muscles without the expulsion of gastric contents; vomiting was defined as the forceful expulsion of gastric contents from the mouth.10 If two or more episodes of emesis occurred, another rescue antiemetic (ondensetron 4 mg) was given. Perioperative complication like hypotension, sedation, shivering and pruritis were observed. Statistical analysis: All data was expressed as Mean ± Standard deviation (SD). Statistical analysis was done using student’s unpaired t-test and ANOVA. p-value <0.05 was considered significant.RESULTS Table 1: Distribution according to Demographic profile (N=150)
p-value <0.05 is taken as significant
Table 2: Distribution of perioperative emetic episodes in groups according to Belville’s score (N=150)
Table 3: Comparison of the incidence of emetic symptoms of the three groups
p-value <0.05 is taken as significant In the intraoperative and post operative period, an emesis free episode according to Belville’s score Grade 0 - No nausea, occurred in 31 of 50 patients (62%), 24 of 50 patients (48%) and 13 of 50 patients (26%) who had received IT Dexmedetomidine, IT fentanyl or IT placebo respectively [Table-II]. Among dexmedetomidine and fentanyl groups, the incidence of retching, nausea and vomiting were less in dexmedetomidine group than fentanyl group; however, that did not differ significantly (p-value>0.05) [Table-III]. Intraoperative rescue antiemetic was required in 7(14%) patients in the control group, however, the requirement was reduced to 3 (6%) in fentanyl group and 2 (4%) patient in the dexmedetomidine group. Table 5: Comparison of Perioperative Complications (N=150)
Shivering was mainly seen in control group and pruritis in fentanyl group. Hypotension was observed in 42 patients in control group, 38 patients in fentanyl group and 42 patients in dexmedetomidine group. [Table-IV].
DISCUSSION In present clinical study, we have compared the efficacy of fentanyl and dexmedetomidine to minimize incidence of nausea vomiting when co administered with hyperbaric bupivacaine (0.5%) intrathecally with that of placebo in caesarean section. Factors such as age, history of motion sickness, hormonal changes, hypotension, pain, surgical procedure and anesthetic technique influence emetic symptoms. However, in present study, study groups were similar with regard to maternal demographics and operative management. Therefore, difference in frequency and severity of emetic symptoms can be attributed to study drugs administered. Nausea and vomiting commonly occur during caesarean section performed under subarchnoid block1, and is frequently related to intraoperative hypotension, peritoneal traction and exteriorization of uterus. These problems may be accompanied by visceral pain that stimulate vagal afferents, which occurs despite apparently adequate dermatomal sensory blockade 2. Various pharmacological agents have been used prophylacticaly, however, either undesirable effects or cost of the agents limited their routine use 11. Intrathecal fentanyl and dexmedetomidine as adjuvants with bupivacaine in subarchnoid block for caesarean section, may provide better intraoperative and postoperative analgesia and thereby decreases discomfort from peritoneal manipulations which may initiate emetic episodes 2,4,12,13. Antiemetic effect of dexmedetomidine may be induced by direct antiemetic properties of α2 agonists through inhibition of catecholamine by parasympathetic tone 11.Intrathecal fentanyl improves the quality of spinal anesthesia increasing both the duration and intensity of spinal anesthesia and decreasing the intraoperative nausea and vomiting 14. The results of present study revealed that both IT fentanyl and IT dexmedetomidine significantly decrease the incidence of intraoperative and early postoperative nausea-vomiting in comparison with placebo (p<0.05), which are in agreement with the observations of 3,7,12-15. Intraoperative rescue antiemetic was required in 7(14%) patients in the control group, however, the requirement was reduced to 3(6%) in the fentanyl group and 2(4%) patient in the dexmedetomidine group which is similar to 11,12,15,16. In present study the incidence of hypotension was also comparable to the observations made by 12,15. Hypotension was aggressively treated with I.V. fluids and I.V. ephedrine. Therefore, the low dose of intrathecal agents did not have any deleterious cardiovascular effects on the parturients. Incidence of bradycardia was more in dexmedetomidine group whereas incidence of shivering was more in the control group and pruritis in fentanyl group.
CONCLUSION From present study it is concluded that, co-administration of intrathecal fentanyl 12.5 μg or intrathecal dexmedetomidine 5 μg with 0.5% hyperbaric bupivacaine in the subarachnoid block significantly reduces intraoperative and postoperative nausea-vomiting in cesarean sections under subarchnoid block. Acknowledgements We express our deep gratitude to all patients for their co-operation.
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