Orthopedic surgeries lead to moderate to severe postoperative pain, treating which is a challenge to the anesthesiologist¹. Regional anesthesia techniques are increasingly trending for upper and lower limb surgeries, as these provide optimal anesthetic care, which includes postoperative analgesia and improved patient satisfaction². Epidural analgesia provides superior analgesia compared with other postoperative analgesic techniques^3,4. Adequate postoperative pain relief will be helpful in early ambulation of the patient as well as hospital discharge⁵. Adjuvants are commonly used with local anaesthetics to increase duration of anaesthesia or improve the quality of analgesia at lesser local anaesthetic dose requirements. Epidural fentanyl has been used effectively as an alternative to morphine and has been shown to induce fewer complications when compared with epidural morphine⁶. Dexmedetomidine is a newer alpha-2 agonist which has got sedative, anxiolytic, analgesic, and hemodynamic effects when used via epidural route^7,8. In our study we compare the efficacy, analgesic effects of epidurally administered dexmedetomidine and fentanyl along with bupivacaine for patients undergoing lower limb orthopaedic surgeries.

Study Setting This study was conducted among the study participants scheduled for orthopedic surgery under Government Thanjavur Medical College Hospital ,Thanjavur by the Department of Anesthesiology .The study was done for a period from August 2022 to July 2023. Study Design Randomized controlled study Sample Size The study participants fulfilling the inclusion and the exclusion criteria were included in the study throughout the study period. The final attained sample is 60. The study participants were grouped into two groups(30 each GroupBF- received 12ml of 0.5 % bupivacaine with 1 μg/kg of Fentanyl epidurally Group BD - received 12ml of 0.5 % bupivacaine with 1 μg/kg of dexmedetomidine epidurally. Inclusion Criteria 1) ASA grade I and II status. 2) 20-65 years of age. 3) Patients giving informed written consent. 4) Patients scheduled to undergo elective lower limb orthopaedic surgery Exclusion Criteria 1. ASA grade III-V 2. Allergy to amide type of local anaesthetics. 3. Contraindication to epidural anaesthesia 4. Objection to epidural anaesthesia Data Collection Method: After obtaining the Institutional Ethical Committee clearance, the study was started after obtaining patients informed consent. The study participants recruited during the study period i.e 60 will undergo the routine investigations and then the preanesthetic fitness. After informed written consent was taken, patients were kept fasting for six hours and received a tablet of alprazolam 0.5 mg at night before the surgery. Upon arrival in the operation room, ASA standard monitors, including non-invasive blood pressure and pulse oximeter were attached and baseline parameters were recorded. The heart rate and rhythm were monitored from a continuous visual display of an electrocadiogram. An intravenous line with an 18G canula was secured and all the patients were preloaded with 15 ml/kg lactated ringer solution. Patients were positioned in siting position. Under strict aseptic precautions L3-L4 space was identified. Skin and subcutaneous tissue was infiltrated with local anaesthetic injection 2% lignocaine 2ml. Epidural space was identified with an 18G Touhy needle, by using loss of resistance to air technique and a Epidural catheter (18 G) was inserted about 5 cms into the epidural space, A test dose of 3 ml of 1.5% lignocaine with 1:200000 adrenaline was administered after negative aspiration of blood and CSF and thereafter epidural catheter was secured in place(padded). Patients were placed supine. The anaesthetist who performed the procedure was blinded to the study. Preparation of the drug combination : 12 ml of 0.5% bupivacaine was taken in 20 ml syringe to which a calculated dose of 1 μg/kg of dexemedetomidine or fentanyl diluted to 1ml using normal saline was added (TOTAL VOLUME OF 13ml) The following solutions were randomly administered: 12 ml of 0.5% bupivacaine with 1 μg/kg of dexemedetomidine in group BD(n=30) and 1μg/kg of fentanyl in group BF (n=30). Supplemental oxygen provided during surgery. The following parameters were observed following the block 1.Time of Onset of Analgesia to T10, 2.Maximum Sensory Level Achieved , 3.Time To Highest Sensory Level 4.Time Taken For Complete Motor Blockade 5.Two Segment Regression Time. 6.Sedation Score 7.Haemodynamic Parameters 8.Side Effects Statistical analysis: The obtained data was entered in MS Excel Windows 10.Statistical analysis was done with the help of SPSS 23.Continuous data was expressed in terms of mean and standard deviation. Categorical data was expressed in terms of Numbers and Percentages. Test of association for Categorical data was Chi square test and for Continuous data was t test and Anova test.p values <0.05 is considered as statistically significant.

Table 1:Demographic profile of the study participants

Table 2: Comparison of onset of analgesia to T10 in minutes between the

groups in the study population.(Unpaired ‘t’ test)

Table 3: Comparison for level of highest sensory blockade achieved above T10 between the groups in the study population. (Fisher’s exact test)

Table 4: Comparison of time to achieve Maximum sensory level blockade

in minutes between the groups in the study population.(Unpaired ‘t’ test)

Table 5: Comparison of time taken in minutes to achieve complete motor

blockade between the groups in the study population. (Unpaired ‘t’ test)

Table 6: Comparison of two segment regression time in minutes between the groups in the study population.(Unpaired ‘t’ test)

Table 7: Comparison of sedation score between group BD and BF

Table 8: Comparison of side effects between group BD and BF

Graph 1. Comparison of Mean arterial blood pressure between two groups

Graph 2. Comparison of Heart Rate between two groups

RESULTS

Sixty patients who underwent major lower limb orthopaedic surgeries were enrolled in the study and divided into two random groups  BF and BD. The demographic characteristics like Age, Sex, Weight, ASA physical status were similar in all groups and did not show any significant statistical difference. (P >0.05) [Table 1]

 The mean time for onset of T10 sensory block is 11.23 ± 1.32 (minutes)in group BF and 8.45 ± 1.57 (mins) in group BD. There was significant difference among two groups in the time for onset of sensory block to T 10 level. (p<0.05). [Table 2]

The highest sensory level of T5 was achieved in more number of patients in group BD compared to group BF. None of patient in group BF achieved T5 level of sensory block, there was statistical significant difference seen in maximum sensory level achieved. (P<0.05) [Table 3]

The time taken to attain maximum sensory level in group BF (18.13 ± 2.1 mins) was compared to group BD (14.50 ± 1.78 mins),Group BD was earlier and statistically significant P Value < 0.005 [Table 4]

In our study , complete motor block was achieved earlier in group BD than group BF. Time for complete motor block was earlier in group BD 17.57 ± 2.84       minutes when compared to group BF  22.33 ± 3.43minutes [Table 5]

In our study the two segment regression time was longer 129.7 ± 5.52minutes in group BD dexmedetomidine and bupivacaine) when compared to 93.25 ± 7.54 minutes in (fentanyl and bupivacaine) group BF. [Table 6] Better sedation score difference was observed at and after 30 mins in (dexmedetomidine and bupivacaine) group BD when compared to (fentanyl and bupivacaine) group BF. [Table 7]

No statistically significant difference was found between both groups of the study, regarding each of systolic BP, diastolic BP, heart rate, SPO2 (%) throughout the whole duration of the surgery(In our study, Pruritus was observed in two patients and nausea/vomiting among one patient in the fentanyl group and in the dexmedetomidine group, hypotension was developed in one patient but it was not statistically significant.

Epidural blockade is often used either as a sole anaesthetic technique or as an adjuvant technique as it reduces the surgical stress response and postoperative pain.We used an exclusive lumbar epidural route in our study so that postoperative analgesia can be provided and also invasive dural penetration was avoided. Addition of opioids to local anesthetics has several benefits such as improved  pain relief, limited regression of sensory blockade, and decreased dose of local anesthetic  Use of lipophilic opioid (fentanyl) is preferred to hydrophilic as it provides rapid onset of action,rapid clearance, and prevents delayed respiratory depression. Dexmedetomidine is a potent and selective α-2 adrenoceptor agonist. It has relatively high ratio of α-2/α-1 activity (1620:1). The improved specificity of dexmedetomidine for α-2 receptor causes it to be with much more effective sedative, anxiolytic, analgesic and sympatholytic properties with less cardiovascular side effect. In the present study, we found that addition of dexmedetomidine to epidural bupivacaine provided effective intraoperative as well as postoperative analgesia comparable to fentanyl with greater patient satisfaction.

In our study, the mean time of onset of the sensory blockade at the T10 level was fastest for dexmedetomidine followed by the fentanyl group which is consistent with the study done by Bajwa SJS et al⁹. The highest sensory level of T5 was achieved in more number of patients in group BD compared to group BF similar to study done by Bajwa SJS et al¹⁰ and Sarabjit Kaur,et al¹¹ In our study , complete motor block was achieved earlier in group BD than group BF concordance with studies of Rashpal Singh Gill at al¹² and Kumkum Gupta et al¹³.Better sedation score difference was observed at and after 45 mins in  group BD when compared to group BF. This result was also concurrent with studies of Rashpal Singh Gill at al¹², Sarabjit Kaur et al¹¹

In our study, the mean time to two-segment regression of sensory blockade was thelongest for the dexmedetomidine group compared to fentanyl group correlate with the study done by Karnawat R,et al¹⁴ and Bhawana Rastogi et al¹⁵. Significant hypotension and bradycardia were not observed in both the groups and this result was correlated with the study of Sukhminder jit singh bajwa, et al

From our study, we conclude that Dexmedetomidine seems to be a better adjuvant to epidural bupivacaine for lower limb orthopaedic surgeries for attaining early onset of sensory and motor block ,maximum level of sensory block, faster onset of highest level of sensory block, providing better sedation and prolonging two segment regression time when compared to epidural fentanyl with minimal side effects

FUNDING:

None of the authors received funding for this study

COMPETING INTEREST:

There is no competing interest

AUTHORS CONTRIBUTION:

All authors in our study contributed to the data collection of the patients

ACKNOWLEDGEMENT:

The authors like to thank the Dean of the Medical College,Head of the Department Anesthesiology ,Thanjavur Medical College and  Hospital,Thanjavur,TamilNadu.

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