Epidural anesthesia is an integral and important component of modern anesthetic practice, as it revolutionizes pain management and surgical procedures [1]. The anesthesiologist places it at any level of the vertebrae to provide anesthesia and analgesia, supplement general anesthesia, decrease the need for a deeper plane of general anesthesia, and provide a stable hemodynamic preoperative course. Currently, it is commonly used in surgeries involving the lower limbs, abdomen, and pelvis [2, 3]. It provides the advantage of controlled anesthesia, allowing adjustable levels of anesthesia, and assuring optimal pain relief while preserving muscle function and sensation, if needed. Lower abdominal and lower limb surgeries have the benefit of avoiding the disadvantages associated with general anesthesia, such as airway manipulation, the use of multiple drugs, and other undesired effects such as postoperative nausea, vomiting, and the need for supplemental analgesics [4]. As early postoperative mobilization and rehabilitation with minimal pain and discomfort are the most desirable features of modern surgical practice, epidural anesthesia has become a desirable technique [5]. It can be used to provide continuous analgesia using infusion pumps for sustained delivery of medication, particularly in postoperative settings. The combined spinal-epidural technique has the advantage of rapid onset of spinal anesthesia and flexibility of epidural analgesia, offering a balanced approach to pain management during labor and surgery [6]. It has now been added to the multimodal analgesia approach, incorporating adjuncts such as opioids and non-steroidal anti-inflammatory drugs to enhance analgesic efficacy while minimizing adverse effects. Supplementation of drugs is possible even during surgery by placement of an epidural catheter. The local anesthetic commonly used in epidural anesthesia is bupivacaine. Bupivacaine, an amide long-acting local anesthetic, is advantageous as it is highly stable. The high potency and long duration of action of its sensory anesthesia are desirable characteristics [7]. Clonidine, a selective partial alpha-2 agonist and aniline derivative, has been used for sedation and as an antihypertensive agent. However, it has some undesirable side effects, such as bradycardia, hypotension, dry mouth, glucose intolerance, and rebound hypertension [8]. Therefore, there is a need for alternative drugs with a better safety profile. Dexmedetomidine, a highly selective alpha-2 agonist, is a very recent and advanced agent. It has sedative, analgesic, and hemodynamic stabilizing effects in addition to reducing anesthetic drug requirements. As Dexmedetomidine is a relatively newer and rapidly emerging drug, we decided to compare its efficacy as an epidural adjuvant with clonidine in our institution in patients undergoing elective infraumbilical surgeries. In this study, we will compare epidural 15ml Bupivacaine 0.5% plus Clonidine 1µg/kg vs 0.5% [9]. Bupivacine 15ml plus Dexmedetomidine 1mcg/kg for infra umbilical surgeries concerning the time of onset of sensory and motor blockade, duration of analgesia, the sedation profile, and adverse effects, if any. The aim of the study is to compare the efficacy of Dexmedetomidine and Clonidine added to Bupivacaine in epidural anesthesia for below-umbilical surgeries [10].

This prospective study was conducted in the Department of Anesthesiology, Kakatiya Medical College, and MGM Hospital, Warangal. After obtaining approval from the hospital's scientific and ethics committee and written informed consent, 60 patients were enrolled in this study. The study population included patients of either sex, ASA Grade 1 and 2, in ages between 20-60 years, all patients posted for elective below umbilical surgeries who underwent epidural procedures were included in this study.

Inclusion criteria

1. Age between 20-60 years
2. Males and Females
3. ASA grade 1 & 2
4. Patients undergoing elective lower limb surgeries, lower abdominal surgeries, urological surgeries, and gynecological procedures.

Exclusion criteria

1. Patient refusal
2. ASA grades 3 & 4
3. Patients on beta blockers and α2 antagonists
4. Patients are allergic to dexmedetomidine clonidine or bupivacaine.
5. Local infection at the site of injection
6. Patients with weight >120kg
7. Patients with height <150cm
8. Pregnant and lactating mothers
9. Uncontrolled hypertension or diabetes mellitus
10. Emergency surgery
11. Hemodynamically unstable patients

Method

Preoperative assessment was done for each patient and written informed consent was taken. Patients were allowed for a period of fasting of 8 hours for solids and 2 hours for clear liquids and were given premedication with Tab. Alprazolam 0.5mg and Tab. Ranitidine 150mg at night before surgery. On the day of surgery, the patient was shifted into the operation theatre, an 18 G cannula was secured and as per ASA standards, all monitors - ECG, Non-Invasive blood pressure, pulse oximeter, temperature skin probe, and basal vital parameters were recorded.  Patients were placed in a sitting position. Epidural space was identified with loss of resistance technique at L2-L3 level using 18G Tuohy's needle. A test dose of 3ml of 1.5%Lignocaine with 1:200000 epinephrine was given after negative aspiration of CSF and blood. After the test dose, in the absence of any adverse sequelae, the total amount of the study drug was given slowly through an epidural needle.

Dexmedetomidine which comes in ampules 1ml contains 100mcg/ml taken in the insulin syringe (1ml capacity). So, 0.1ml contains 10mcg. According to the body weight, dexmedetomidine solution was added to 0.5% Bupivacaine solution. In our study, we were taking 1mcg/kg of Dexmedetomidine. Clonidine which comes in 1ml ampoules, each ampoule having 150mcg was taken similarly in a 1ml syringe and added as 1mcg/kg to 0.5% Bupivacaine solution. Intraoperatively, the onset of sensory and motor blockade, maximum level of sensory blockade attained and duration of sensory and motor blockade were noted. Any intraoperative events like hypotension, bradycardia, shivering, nausea, and vomiting were recorded. After the surgery, patients were shifted to the recovery room where they remained until complete recovery of sensory and motor blocks. Postoperatively, vital parameters were monitored.

Parameters studied were onset of sensory block, Maximum level of sensory block attained and time taken for the same, Regression time, onset and duration of motor blockade, and Sedation, with the Ramsay sedation scale as a reference, sedation scores were recorded just before the initiation of surgery and thereafter every 30 minutes during surgical procedure, finally taking the mean sedation score in each individual, and complications if any. Heart rate <60 bpm was considered as bradycardia and treated with Inj. Atropine 0.6mg IV. Systolic blood pressure of <90mm hg was considered hypotension and treated with Ink. Mephenteramine 6 mg intravenous boluses. Nausea and vomiting were treated with Inj. Ondansetron 4mg IV. Shivering was treated with Inj Tramadol 0.5mg/kg I.V

Statistical Analysis

The collected data was entered into Microsoft Excel Worksheet-2010 and data was taken into IBM SPSS Statistic for Windows, version 24 (IBM Corp., Armonk, N.Y., USA) software for calculation of frequency, percentage, mean, standard deviation, and probability value. Qualitative data was represented in the form of frequency and percentage. The association between qualitative variables was assessed by the Chi-Square test and Fisher's exact test. The values of p (<0.05) were considered as significant.

This prospective, randomized, double-blinded comparative study was conducted in the Department of Anaesthesiology, Kakatiya Medical College, Warangal, over 24 months (September 2022–August 2024). Sixty patients undergoing elective lower abdominal, lower limb, urological, and gynecological surgeries were enrolled and randomized into two groups (n=30 each) based on the adjuvant used with epidural bupivacaine:   Group D: 15 mL of 0.5% bupivacaine + 1 µg/kg dexmedetomidine   Group C: 15 mL of 0.5% bupivacaine + 1 µg/kg clonidine. The demographic profile, anthropometric measurements, and ASA physical status were comparable between groups (all p > 0.05) (Tables 1–3).  The mean age in groups A and B was 44.9 ± 3.43 years and 45.13± 3.06 years respectively. The p-value calculated was 0.2871 indicating no statistical difference.

The majority of subjects in group D were males, i.e., 18 subjects (60 %), followed by 12 females (40 %). The majority of subjects in group C were males, i.e., 16 subjects (53.33 %), followed by 14 females (46.66 %). The statistical P value calculated was 0.3804 which indicated that there was no statistical difference between the groups in terms of gender-wise distribution of subjects of the subjects (Table 2).

The majority of subjects in group D came under ASA category I, n=20 subjects (66.67 %) followed by 10 subjects (33.33 %) under ASA category II. The majority of subjects in group C came under ASA category I, n= 23 subjects (76.67 %) followed by 7 subjects (23.33%) under ASA category II. The statistical p-value calculated was 0.3804which indicated that there was no statistical difference between the groups in terms of ASA categories-wise distribution of the subjects (Table 3).

Block Characteristics: Dexmedetomidine demonstrated a significantly faster onset of sensory (4.38 ± 1.05 vs. 6.08 ± 1.15 min; p = 0.01) and motor blockade (8.19 ± 1.42 vs. 10.95 ± 2.31 min; p = 0.01) compared to clonidine (Table 4). The duration of both sensory (7.85 ± 1.05 vs. 7.12 ± 1.15 hrs; p = 0.01) and motor blockade (7.89 ± 1.45 vs. 7.15 ± 1.13 hrs; p = 0.01) was prolonged in Group D. 

                                *Significant

Hemodynamic and Oxygenation Parameters: No significant intergroup differences were observed in heart rate, systolic/diastolic blood pressure, mean arterial pressure, or SpO₂ at any time point (all p > 0.05).   Analgesic Efficacy: Group D exhibited superior analgesia, evidenced by: Lower Verbal Rating Scale (VRS) scores at all intervals (0–24 hrs; p ≤ 0.05) (Table 5).  Delayed time to first rescue analgesia (8.38 ± 1.46 vs. 8.00 ± 1.89 hrs; p = 0.05).  Sedation and Adverse Effects: Group D had significantly higher proportions of patients with a sedation score of 3 (46.66% vs. 10%; p = 0.005).  Side Effects: Nausea (13.33% vs. 16.67%), vomiting (10% vs. 6.67%), and shivering (10% vs. 13.33%) were comparable (p = 0.0652). 

Epidural anesthesia is a preferred anesthesia for below the umbilicus surgeries and its effectiveness in providing analgesia with fewer side effects makes it the procedure of choice. The addition of adjuvants such as clonidine and dexmedetomidine has been shown to enhance the quality and duration of analgesia. Dexmedetomidine is a highly selective α2-adrenergic agonist. It prolongs the sensory block and improves postoperative analgesia by modulating the nociceptive pathway and reducing sympathetic activity [11]. In addition, it does not cause respiratory depression. [12] Clonidine is an α2A-adrenergic receptor agonist with similar benefits associated with increased sedation and hypotension however, it is less selective. The use of these adjuvants has demonstrated a reduction in opioid requirements and improved recovery profiles [13]. The current study was done in two groups of patients Group D (dexmedetomidine) and Group C (clonidine). Demographic characteristics including age, gender, height, weight, and ASA classification showed no statistically significant differences between groups which shows equal distribution in both groups. A similar pattern of distribution was also followed by other studies by Bajwa SJ et al. [14], Godugula VDSNH et al. [15], Bhati K et al. [16], and others [11, 12].

In this study, we found the mean onset time of sensory was significantly shorter in group D (4.38 ±1.05 min and 8.19 ±1.42 min) as compared to group C (6.08 ±1.15 min and 10.95 ±2.31 min), with p = 0.01. Similarly, the duration of motor block was significantly longer in Group D (7.85 ±1.05 and 7.89 ±1.45 hours) than in Group C (7.12 ±1.15 and 7.15 ±1.13 hours) similar findings have been reported by previous studies in this field. [17, 18]. The duration of surgery did not differ significantly between the two groups with a mean duration of 2.12 ±0.05 hours in Group D and 2.93 ± 0.02 hours in Group C (p = 0.586) which is in concordance with findings of other studies [36–38]. The results of this study also showed that no statistically significant differences were found in both groups in comparison for heart rate, systolic, diastolic, and mean arterial pressure. The SpO2 values remained similar in both groups at various time intervals post-block. This indicates that both adjuvants were similar in maintaining hemodynamic stability throughout the perioperative period [19, 20].

The assessment of pain using the verbal pain intensity scale found consistently lower scores in group D compared to group C at 0, 2, 4, 6, 12, and 24 hours, and all the p values were ≤ 0.05, indicating superior analgesia in the dexmedetomidine group. The time for the first rescue analgesic was slightly longer in group D 8.38 ±11.46 hours) compared to Group C (8 ±11.89 hours), which showed Group D had an overall lesser requirement for rescue analgesic as compared to Group C. The incidence of side effects which included nausea, vomiting, and shivering were comparable between the two groups, with no statistically significant differences. Both appear to be equally safe in this study [11-13]. Therefore, from all the above results we found that dexmedetomidine provides superior analgesia with faster onset and prolonged duration of blocks compared to clonidine without altering hemodynamic stability. It has a good safety profile with fewer adverse effects which makes it an adjuvant of choice in epidural anesthesia for infraumbilical surgeries.

Our study comparing dexmedetomidine and clonidine added to bupivacaine in epidural anesthesia for below-umbilical surgeries found no significant differences in age, sex, height, weight, ASA category distribution, heart rate, blood pressure, and SpO2 levels. However, the dexmedetomidine group exhibited faster onset and longer duration of sensory and motor blocks than the clonidine plus bupivacaine group. Additionally, dexmedetomidine required rescue analgesics after clonidine was added to bupivacaine. Dexmedetomidine added to bupivacaine consistently reported lower VRS scores across all time points, while incidences of side effects did not significantly differ between the groups. Hence our study concludes that dexmedetomidine is a better add-on agent to bupivacaine in epidural anaesthesia for below umbilical surgeries.

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