Comparative Study of Effects of Dexmedetomidine as Adjuvant to Bupivacaine and Bupivacaine Alone in Epidural Anesthesia

DOI: 1.17354/SUR//13 Original Article Comparative Study of Effects of Dexmedetomidine as Adjuvant to Bupivacaine and Bupivacaine Alone in Epidural Anesthesia Vishwadeep Singh 1, Geeta Singh, Priyank Srivastava 3, Lalit Singh 4 1 Senior Resident, Department of Anaesthesia, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India, Assistant Professor, Department of Anaesthesia, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India, 3 Postgraduate Student, Department of Anaesthesia, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India, 4 Professor and HOD, Department of Pulmonary Medicine, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India Abstract Background: Epidural anesthesia is one of the most used anesthetic technique for a lower abdominal and lower limb surgeries. Aim: The aim of the present study was to compare dexmedetomidine as an adjuvant with bupivacaine with plain bupivacaine in epidural anesthesia with respect to onset and duration of sensory and motor block, duration of analgesia, hemodynamic changes, adverse effects and sedation. Materials and Methods: A total of 6 patients of either sex with age ranging from 18 to 65 years and belonging to ASA Grades I and II physical status, scheduled for surgery under epidural anesthesia. The patients were divided into two groups with 3 patients each. Group 1 was given ml.5% plain bupivacaine +.5 ml saline and Group was given ml.5% plain bupivacaine + 1 µg/kg dexmedetomidine. Results: The time of sensory onset up to T1 was shorter in Group (7.1 ±.1 min) as compared to Group 1 (15. ±.6 min). The time of motor block onset to bromage 3 was shorter in Group (14.5 ± 5.18 min) as compared to Group 1 (.36 ± 3.4 min). The time of motor block regression to bromage was longer in Group (48.7 ± 8.4 min) as compared to Group 1 (15 ± 1. min). The time of sensory block regression and the duration of analgesia were also longer in Group. Conclusion: Dexmedetomidine seems to be a good choice as an adjuvant with bupivacaine in epidural anesthesia. Keywords: Analgesia, Bupivacaine, Dexmedetomidine, Epidural, Modified bromage scale, Pin prick INTRODUCTION International Association for the study of Pain has defined pain as an unpleasant sensory and emotional experience associated with actual or potential damage or described in terms of such damage. There are ample reasons to believe that pain is inherent to life. And so is the looking for the methods of pain relief. Many techniques and drug www.surgeryijss.com Access this article online Month of Submission : 11-15 Month of Peer Review : 1-15 Month of Acceptance : 1- Month of Publishing : - regimens, with partial or greater success, have been tried from time to time by the mankind for the relief of pain. 1 The introduction of regional anesthesia in the form of epidural anesthesia has markedly changed the method of pain relief both during surgical procedures and other pain symptoms. Epidural anesthesia is unique in that it allows the titration of the dosage to attain the desired anesthesia, analgesia and motor relaxation. This has a potential sparing effect on the amount of sedative needed without compromising patient comfort, and decreases the risk of over sedation. It is popular and offers several benefits to the patients, most importantly staying awake, early family contact, and early food intake. 3 It can provide desired analgesia even after the procedure has completed. It can also provide analgesia in patients needing conservative management. Improvements in equipment, drugs and technique have made it a popular Corresponding Author: Dr. Vishwadeep Singh, Room No.11, F Block, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India. E-mail: vishwadeepvishen@gmail.com IJSS Journal of Surgery March-April Volume Issue 7

and versatile anesthetic technique, with applications in surgery, obstetrics and pain relief. Its versatility means it can be used as an anesthetic, as an analgesic adjuvant to general anesthesia and for post-operative analgesia in procedures involving the lower limbs, perineum, pelvis, abdomen and thorax. For the anesthesiologist, cardiovascular and respiratory stability, rapid postoperative recovery and the preservation of protective airway reflexes are the most important advantages of epidural anesthesia. 4 Local anesthetics like bupivacaine for epidural anesthesia through epidural catheter have been used with great success, but with the intro duction of potent and shortacting opioids like fentanyl and later other adjuvants, have decreased the dose requirement of local anesthetics, increased their onset of action, prolonged their action and improved the analgesia with decreasing the side effects of local anesthetics. In this regard, the newer α- adrenergic agonists such as dexmedetomidine and clonidine are now being used with great success. They have both analgesic and sedative properties when used as an adjuvant in regional anesthesia. 5 The aim of the present study was to compare dexmedetomidine as an adjuvant to bupivacaine with plain bupivacaine in epidural anaesthesia with respect to onset and duration of sensory and motor block, duration of analgesia, hemodynamic changes, sedation and adverse effects. MATERIALS AND METHODS After obtaining Institutional Ethical Committee approval and informed written consent from patients, the study was performed on 6 patients of either sex, between 18 and 65 years of age and belonging to ASA Grades I and II physical status. Patients with the history of uncontrolled labile hypertension, heart block, dysrhythmia, on cardiac medication (adrenergic receptor antagonist, calcium channel blocker or angiotensin-converting enzyme inhibitor), addiction to narcotic, patient posted for lower segment caesarean section and with any contraindication to epidural anesthesia were not included in the study. The patients were randomly divided into two groups with 3 patients each. Group 1 (control): ml.5% plain bupivacaine +.5 ml saline (preservative free). Group (dexmedetomidine): ml.5% plain bupivacaine + 1 µg/kg dexmedetomidine. In each group, equal volume was injected. All patients were preloaded with 15 ml/kg of ringer lactate. In the operation theatre pulse oximetry (Spo), non-invasive blood pressure and electrocardiography (ECG) were monitored and in sitting posture epidural catheter was placed into L-L3 or L3-L4 epidural space under strict aseptic conditions, using Tuohy s needle with LOR technique. Onset, duration and quality of anesthesia were assessed. Sensory block was assessed bilaterally by a short hypodermic needle in mid clavicular line. Motor block was assessed by modified bromage scale. Sedation was assessed by modified Ramsay scale. Hemodynamic changes viz. pulse rate and rhythm, blood pressure BP, ECG were recorded at regular intervals in preoperative, intraoperative and in post-operative period. Any other untoward incidence such as nausea, vomiting, shivering, pruritus, respiratory depression and sedation was assessed. The changes in above parameters were clinically and statistically compared with the control group. Statistical analysis was done using the statistical package (SPSS 15. evaluation version). Data are expressed as either mean and standard deviation or numbers and percentages. Continuous co-varieties were compared using Analysis of Variance. The qualitative data comparison was done using the Chi-square test. The p value was reported at the 95% confidence interval. P <.5 was considered statistically significant. P >.5 was considered statistically non-significant. RESULTS The age distribution remains comparable and statistically insignificant in both age groups having P >.5 (Table 1). The sex distribution remains comparable in both the groups and statistically insignificant in both the groups having P >.5 (Table ). There were no significant differences between the groups according to the type of surgery and distribution remain comparable and statistically insignificant in both groups having P >.5 (Table 3). It is evident from the Table 4 that the time of sensory onset was the shorter (7.1 ±.1) min in Group as compared to Group 1 (15.±.6) min. The difference in time of sensory onset is statistically significant (P <.5). It is evident from Table 5 motor block onset to Bromage 3 was shorter in Group (14.5 ± 5.18) min as compared to Group 1 (.36±3.4) min. The difference in time of motor block onset is statistically significant P <.5. It is evident from Table 6 that time of sensory regression to S1 was the longer in Group (3.6 ± 38.3) min as compared to Group 1 (196 ± ) min. The difference in time of sensory regression to S1 is statistically significant P <.5. It is evident from the Table 7 that the time of motor block regression to Bromage was longer in Group (dexmedetomidine) as compared to Group 1 (control). The difference in time of the motor block is statistically significant P <.5. As shown in Graph 1, the systolic BP was comparable at baseline (>.5). After 5 min, the systolic BP (SBP) starts falling in each group, but fall in SBP was statistically significant (P <.5) in Group as compared to Group 1. SBP returned to baseline after 8 IJSS Journal of Surgery March-April Volume Issue

45 min. After 9 min in each group SBP was comparable, i.e., (P >.5). As shown in Graph diastolic BP (DBP) was comparable at baseline (P >.5). After 5 min DBP fell in each group, but fall in DBP was statistically significant (P <.5) in Group as compared Group 1. After 45 min, there was no statistically significant change in (P >.5) in DBP in both groups. As shown in Graph 3 Table 8, the heart rate was comparable at baseline (P >.5) though there was fall in heart rate, but there was no significant difference (P >.5) in heart rate in between different groups. The mean sedation score was significantly higher in Group as compared to (Group 1) (Graph 4). It is evident from Table 8 and Graph 5 that duration of analgesia (338 ± 3.15 min) was more in Group than in Group 1 (Bup) (18 ± 5 min). The difference in analgesia duration was statistically significant (P <.5). Dry mouth was the most common side effect in both groups but more in 14 1 1 Table 1: Distribution of patients according to their age Mean age in years Bupivacaine (Group 1) Dexmedetomidine (Group ) <18 18 7 8 38 11 1 39 48 18 49 58 3 59 65 Total 3 3 Mean±SD 41.36±6.46 4.36±7.1 SD: Standard deviation, P>.5 Table : Distribution of patients according to their sex Group Male Female Total P value Group 1 (control) 14 3.948 Group (dexmedetomidine) 15 15 3 >.5 Table 3: Distribution according to their type of surgery Surgery Control Dexmedetomidine P value Bupivacaine 1 Group Exp.lap 5 7 >.5 TAH 6 5 VH 7 6 Lower limb 5 7 Orthopedic surgery 7 6 Total 3 3 Table 4: Time of sensory onset/block up to T 1 (in minutes) Group P value (control) (dexmedetomidine) Mean±SD 15.±.6 7.1±.1 <.5 Number of cases 3 3 SD: Standard deviation Table 5: Time of motor onset to bromage 3 (in minutes) Group P value (control) (dexmedetomidine) Mean±SD.36±3.4 14.5±5.18 <.5 Number of cases 3 3 SD: Standard deviation BP in mmhg 8 6 4 O min 6min 1min 3min 6 min 9min 1min 15min 18 min 1min 4min 7min 3 min 33min 36min Time Graph 1: Variation in systolic blood pressure BP in mmhg 9 8 7 6 5 4 3 1 min 6min 1min 3min 6min 9min 1min 15min 18min 1min 4min 7min 3min 33min 36min Time Graph : Variation in diastolic blood pressure HR/min Variation in Heart Rate 9 8 7 6 5 4 3 1 Graph 3: Variation in heart rate Group Dexmed Grp 1 Control Grp Dexmed Group Dexmed IJSS Journal of Surgery March-April Volume Issue 9

sedation score 18 14 1 1 8 6 4 S1 S S3 S4 Graph 4: Ramsay sedation score Group Dexmed Table 6: Time of sensory regression to S 1 (in minutes) Group P value (bupivacaine) (dexmedetomidine) Mean±SD 196± 3.6±38.3 <.5 Number of cases 3 3 SD: Standard deviation Table 7: Time of motor block regression to bromage (in minutes) Group P value bupivacaine dexmedetomidine Mean±SD 15±1. 48.7±8.4 <.5 Number of cases 3 3 SD: Standard deviation, P<.5 Table 8: Duration of analgesia (in minutes) (control) Group (dexmedetomidine) Mean±SD 18±5 338±3.15 SD: Standard deviation, P<.5 Time in Min 35 3 5 15 1 5 Mean Graph 5: Duration of analgesia Group Dexmed Group as compared to control Group 1. However, it was statistically non-significant. The incidence of other side effects like nausea, vomiting, headache, shivering and dizziness was comparable in all the groups and statistically non-significant (P >.5) (Table 9 and Graph 6). DISCUSSION The present study entitled a comparative study of dexmedetomidine as an adjuvant to bupivacaine and plain bupivacaine in epidural anesthesia was designed to compare the efficacy of epidural dexmedetomidine 1 mcg/kg and as an adjuvant to.5% bupivacaine in epidural anesthesia with respect to onset and duration of sensory and motor block, duration of analgesia, hemodynamic changes and adverse effect of drugs. The study was performed on 9 patients of ASA Grades I and II of either sex between 18 and 65 years of age, scheduled for lower abdomen and lower limb surgeries. Base Line Comparison of Groups The study included the patients of age group between 18 and 65 years of age. In the present study, the age Table 9: Side effects Side effects Group 1 Group P value Nausea 3 5 >.5 Vomiting 1 1 Shivering 1 Dry mouth 5 7 Headache 1 Urinary retention 1 3 (mean ± standard deviation) in Group 1 was 41.36 ± 6.46 years and in Group 4.36 ± 7.1 years. The age is comparable in both groups (Table 1 and Graph 7). Distribution according to sex was also comparable between the two groups (Table and Graph 8). Time of Sensory Onset (in Minutes) In our study, time of sensory onset to T-1 in Group 1 was 1. ±.6 min, and in Group 7.1 ±.1 min. The onset of sensory block was shortest in Group as compared to Group 1 and thus dexmedetomidine as an adjuvant shortens the time of sensory onset as compared to bupivacaine alone. Hanoura et al. 6 studied intra-operative conditions and quality of post-operative analgesia after adding dexmedetomidine to epidural bupivacaine and fentanyl in the elective caesarean section using combined spinal-epidural anesthesia. They used 1 mcg of dexmedetomidine with bupivacaine; the time of sensory onset was 7. ± 1.8 min. This time is comparable with our time of onset. Manal et al. 7 used ml.5% levobupivacaine and 1.5 mcg/kg dexmedetomidine in epidural anesthesia. The time of sensory onset was 1.6 ± 5.9 min. They concluded that dexmedetomidine is a good alternative to morphine as an adjuvant to levobupivacaine in epidural anesthesia in major abdominal surgeries. Bajwa 3 IJSS Journal of Surgery March-April Volume Issue

No. of pateints 7 6 5 4 3 1 Nausea Vomiting Shivering Dry mouth Graph 6: Side effect No. Of patient 18 14 1 1 8 6 4 11 1 Headache Urinary retention <18 18-7 8-38 39-48 49-58 59-65 Age 18 Group 1 Group et al., 8 used 17 ml of.75% ropivacaine and 1.5 mcg/kg of dexmedetomidine. The time of onset of sensory block to T-1 was 8.5 ±.36 min. This time is comparable with our study. Time of Motor Block Onset (in Minutes) In our study time of motor block onset to bromage in Group 1 was.36 ± 34 min and in Group 14.5 ± 5.18 min. The onset was earlier in Group as compared 3 Bupivacaine Demedetomidine (Gp) Graph 7: Distribution of patients according to their age 15.5 15 14.5 14 13.5 13 Graph 8: Sex Grp -1(control) Grp-(dexmd.) Male Female to Group 1. That is dexmedetomidine as adjuvant shortens the time of motor block onset. Hanoura et al. 6 used 1 mcg/kg of dexmedetomidine with bupivacaine; the time of motor onset was 11.5 ± 4.18 min. This time is comparable with our study. Manal et al. 7 used ml of.5% levobupivacaine and 1.5 mcg/kg dexmedetomidine in epidural anesthesia. The time of motor onset was 18. ± 4.48 min. This time of onset is comparable with our study. Bajwa et al. 9 used 17 ml of.75% ropivacaine and 1.5 mcg/kg of dexmedetomidine. The time of motor onset was 17.4 ± 5. min. This time is comparable with our study. Time of motor block regression (in min): In our study, time of motor block regression to bromage in Group 1 was 15 ± 1. min, and in Group 48.7 ± 8.4 min. The time of motor was longer in Group as compared to Group 1. That is the adjuvant prolonged the time of motor block regression. Hemodynamic Changes Baseline systolic BP, diastolic BP, heart rate, oxygen saturation were comparable. After epidural anesthesia, there was fall in systolic, diastolic BP and HR in each group, but fall in Group was more as compared to Group 1. But after 45 min, they returned to baseline values. Although fall in BP was more in Group, but not statistically significant. There was no statistically significant difference (P >.5) in heart rate in between the two groups. Similar results were also found by Bajwa et al. 1 Bajwa et al. 11 Gupta et al., 1 Syal et al. 13 They all had observations similar to our study. Sedation (Ramsay Sedation Score) Sedation score was more in Group between 6 and 1 min and then in Group 1. Bajwa et al., 9 also found that dexmedetomidine had much better sedation level. Rajini Gupta, Reetu Verma et al., found that sedation score was more in dexmedetomidine than other group. CONCLUSION It can be concluded from this study that dexmedetomidine when given epidural with bupivacaine produces synergistic effect of profound and prolonged motor block, prolonged sensory block and analgesia prolonged to the postoperative period with minimal side effects. Thus, dexmedetomidine can be a good alternative choice to opioids as an adjuvant to bupivacaine for the epidural blockade in lower abdominal and lower limb surgeries. REFERENCES 1. Höhener D, Blumenthal S, Borgeat A. Sedation and regional anaesthesia in the adult patient. Br J Anaesth IJSS Journal of Surgery March-April Volume Issue 31

8;1:8-.. Némethy M, Paroli L, Williams-Russo PG, Blanck TJ. Assessing sedation with regional anesthesia: Inter-rater agreement on a modified Wilson sedation scale. Anesth Analg ;94:73-8. 3. De Andrés J, Valía JC, Gil A, Bolinches R. Predictors of patient satisfaction with regional anesthesia. Reg Anesth 1995;:498-55. 4. Asehnoune K, Albaladejo P, Smail N, Heriche C, Sitbon P, Gueneron JP, et al. Information and anesthesia: What does the patient desire?. Ann Fr Anesth Reanim ;19:577-81. 5. Kamibayashi T, Maze M. Clinical uses of alpha -adrenergic agonists. Anesthesiology ;93:1345-9. 6. Hanoura SE, Hassanin R, Singh R. Intraoperative conditions and quality of postoperative analgesia after adding dexmedetomidine to epidural bupivacaine and fentanyl in elective cesarean section using combined spinal-epidural anesthesia. Anesth Essays Res 13;7:8-7. 7. Kamal MM, Sahar M. Comparative study of epidural morphine and epidural Dexmedetomidine used as adjuvant to levobupivacaine in major abdominal surgeries. Egypt J Anaesth 14;39:137-41. 8. Bajwa SJ, Bajwa SK, Kaur J, Singh G, Arora V, Gupta S, et al. Dexmedetomidine and clonidine in epidural anaesthesia: A comparative evaluation. Indian J Anaesth 11;55:1-1. 9. Bajwa SJ, Arora V, Kaur J, Singh A, Parmar SS. Comparative evaluation of dexmedetomidine and fentanyl for epidural analgesia in lower limb orthopedic surgeries. Saudi J Anaesth 11;5:365-7. 1. Bajwa SJ, Bajwa SK, Kaur J. Comparison of epidural ropivacaine and ropivacaine clonidine combination for elective cesarean sections. Saudi J Anaesth 1;4:47-54. 11. Bajwa SJ, Arora V, Kaur J. Comparative evaluation of dexmedetomidine and fentanyl for epidural analgesia in lower limb orthopaedic surgeries. S J Anaesth 11;4:365-7. 1. Gupta S, Raval D, Patel M, Patel N, Shah N. Addition of epidural clonidine enhances postoperative analgesia: A double-blind study in total knee- replacement surgeries. Anesth Essays Res 1;4:7-4. 13. Syal K, Dogra R, Ohri A, Chauhan G, Goel A. Epidural labour analgesia using Bupivacaine and clonidine. J Anaesthesiol Clin Pharmacol 11;7:87-9. How to cite this article: Singh V, Singh G, Srivastava P, Singh L. Comparative Study of Effects of Dexmedetomidine as Adjuvant to Bupivacaine and Bupivacaine Alone in Epidural Anesthesia. IJSS Journal of Surgery ;():7-3. Source of Support: Nil, Conflict of Interest: None declared. 3 IJSS Journal of Surgery March-April Volume Issue