Regional anesthesia offers significant advantages in providing optimal surgical conditions and prolonged postoperative pain relief [1]. The versatility of epidural blockade, in particular, has made it a cornerstone of modern anesthesiology, surpassing spinal anesthesia in adaptability. Unlike spinal anesthesia, epidural blockade offers clinicians the flexibility to achieve effective surgical anesthesia while catering to extended surgical durations and providing prolonged postoperative analgesia. Moreover, epidural anesthesia reduces the incidence of hemodynamic fluctuations by producing segmental anesthesia, thus minimizing sympathetic blockade compared with subarachnoid block anesthesia [2]. The emergence of regional anesthesia techniques, especially spinal anesthesia, has transformed the landscape of anesthesia administration, particularly in lower limb and lower abdominal surgeries [3]. Traditionally, Bupivacaine 0.5% heavy has been the preferred agent for intrathecal use in spinal anesthesia due to its efficacy. Bupivacaine, a widely used long-acting local anesthetic known for its high lipophilicity, has been a mainstay in anesthesia practice. However, similar to other amide-type anesthetics, investigations into the underlying mechanisms of local anesthetic-induced cardiotoxicity have directed efforts toward finding fewer toxic alternatives to bupivacaine, focusing on amide-linked agents composed of a single enantiomer [4]. However, concerns regarding its acute life-threatening cardiotoxicity have spurred efforts to identify safer alternatives, leading to the development of Ropivacaine, a relatively new amide-type local anesthetic. Ropivacaine offers several advantages over bupivacaine, primarily because of its unique chemical structure. As a p pure s ' enantiomer, Ropivacaine exhibits lower lipid solubility and reduced cardiotoxicity. Furthermore, it demonstrated easier reversibility after inadvertent intravascular injection, decreased central nervous system toxicity, and a more favorable sensory-to-motor block ratio [5]. In the context of epidural anesthesia, Bupivacaine has long been favored for its efficacy in providing anesthesia and postoperative analgesia.5 However, concerns regarding its cardiac toxicity, particularly after accidental intravascular injection, have prompted a search for safer alternatives.  Ropivacaine's more favorable toxicity profile makes it an appealing option for epidural anesthesia, with studies demonstrating its effectiveness in various surgical procedures, including elective cesarean sections and post-operative analgesia for abdominal surgeries [5-8]. Notably, the motor blockade induced by 0.75% Ropivacaine closely resembles that of 0.5% bupivacaine, indicating its potential as an effective alternative in regional anesthesia procedures. Despite the growing interest in Ropivacaine for regional anesthesia, there is a paucity of research specifically investigating its use in epidural anesthesia for lower abdominal surgeries. Therefore, this study aimed to bridge this gap by evaluating the efficacy of intrathecal Ropivacaine heavy 0.75% compared to intrathecal Bupivacaine heavy 0.5% for lower abdominal and lower limb surgery under spinal anesthesia.

This prospective observational study was conducted in the Department of Anesthesiology, Kakatiya Medical College and Hospital, Warangal from September 2022 to August 2024. Institutional Ethical approval was obtained for the study. Written consent was obtained from all the participants of the study.

Inclusion Criteria

1.Patients who gave informed written consent.

2.Patients who were of ASA grade I or II.

3.The age range considered was 20-65 years old.

4.Patients of both gender

Exclusion Criteria

1.Patients who refuse consent to participate in the study.

2.Patients of ASA grade 3 and 4.

3.Patients with medical disorders.

4.Patients with pre-existing neurological and spinal disorders

5.Patients are allergic to local anesthetics.

6.Patients on anticoagulants/coagulation disorder

Sampling Procedure: 60 patients aged 20 to 65 years admitted to Kakatiya Medical College, Warangal, Telangana for lower abdominal surgeries were assigned a unique identification number (starting from 1 to 60).

Randomization: Subjects complying with the inclusion criteria were randomly assigned with a unique identification number (starting from 1 to 60) in opaque sealed envelopes. The participants were randomly divided into two groups of patients based on unique identification numbers, with odd unique identification numbers assigned to group R, and even to group B to ensure that each patient had an equal chance of being in either group. Allocation was performed by the examiner with the allocation ratio intended to be equal.

Demographics: The age and sex of the study participants were recorded. Analgesic efficacy: Evaluated by observing time for onset and duration of sensory blockade, motor blockade time for maximum sensory blockade, and motor blockade duration of analgesia. Hemodynamic stability assessment was done by examining heart rate, pulse rate, and mean arterial pressure and adverse effects were monitored.

Brief procedure: Upon arrival in the operating theatre, standard monitoring devices including pulse oximetry for saturation, non-invasive blood pressure (NIBP), and electrocardiography (ECG) were applied, and baseline parameters including heart rate, blood pressure, and oxygen saturation were recorded. The patient was placed in a left lateral position or sitting position. With all aseptic precautions, a skin wheal was raised in L3-L4 interspace with 2ml of 2% Lignocaine. An 18 G Touhy needle was passed through this space for about 1cm. The stylet was removed and a 10ml dry glass syringe with an air column of 5ml was firmly attached to the hub of the Touhy needle.  The needle was slowly advanced until it entered the epidural space, which was identified by the loss of resistance to air. Once the epidural space was confirmed, the glass syringe was disconnected. The absence of blood or CSF was verified. An 18G epidural catheter was passed through the epidural space in the cephalad direction until 3cm was in the space. 3ml of 2% Lignocaine with adrenaline 1:200000 was given as a test dose. This is to exclude the presence of a needle in an epidural vein or subarachnoid space. 4 minutes later, 20 ml of the study drug was injected through the epidural catheter intermittently over 3 minutes. All the patients were monitored for cardio-respiratory problems, and side effects if any, and were given supplemental oxygen. Fluid management was done according to requirements including fluid deficit maintenance, blood loss, etc.

The analgesic efficacy was evaluated by observing the time for onset and duration of sensory blockade, motor blockade, time for maximum sensory blockade, and motor blockade, as well as the duration of analgesia. Postoperatively, pulse rate and NIBP were continuously monitored to assess any changes or abnormalities. Additionally, adverse effects were closely assessed to ensure patient safety and comfort. All the collected data were entered into Excel for further analysis, allowing for a comprehensive evaluation of the outcomes and efficacy of the analgesic interventions utilized in the study.

Statistical Analysis: The statistical analysis was carried out using IBM SPSS (Statistical Package for Social Sciences) statistical version 27.0. The analysis includes a frequency table, bar, pie chart, and association of variables based on the Chi-square test Normality of data was checked by Kolmogorov–Smirnov tests of normality. For normality distributed data, the Mean was compared with respect to the t-test (for two groups). All statistical tests were seen at a two-tailed level of significance (p≤0.05).

The baseline characteristics of patients of two groups 0.75% Ropivacaine and 0.5% Bupivacaine for epidural anesthesia are given in Table 1. The mean age of the cases of the Ropivacaine group was 46.6 ± 11.41 years and the Bupivacaine group was 43.17 ± 13.13 years and the p values were (0.284) which is statistically not significant. The gender distribution between the groups shows that there was a higher proportion of males in both groups 60% in the Ropivacaine group and 53.3% in the Bupivacaine group however, the p values were not found to be significant. The absence of significant differences between the groups shows that the groups were comparable in baseline characteristics which allows valid comparison of drug effects.

Table 2 shows the key differences in the onset and duration of sensory and motor blockade between the two groups of the study.  A critical analysis of the table shows that the onset of sensory and motor block was significantly faster with Bupivacaine (1.86 ± 0.65 min and 6.1 ± 0.94 min) compared to Ropivacaine (2.26 ± 0.91 min and 6.69 ± 0.98 min), with p-values of 0.034 and 0.022, respectively. However, Bupivacaine showed significantly longer durations for sensory block (192.63 vs. 161.54 min, and p = 0.004), motor block (155.33 vs. 122.93 min, and p = 0.002), maximum sensory block (228.03 vs. 220.07 min, and p = 0.044), and maximum motor block (197.73 vs. 157.67 min, p < 0.001). Interestingly, Ropivacaine offered a longer duration of analgesia (249.2 vs. 232.0 min, and p < 0.001), making it potentially more favorable for prolonged postoperative pain relief.

                          *Significant

The comparison of adverse effects between the groups is given in Table 3. There was a higher rate of adverse events in the Bupivacaine group compared with the Ropivacaine group. There was an incidence of hypotension in 23.3% of the patients using Bupivacaine as opposed to 10% in the Ropivacaine group but this was not significant (p=0.149). The other side effects like bradycardia, shivering, and nausea/vomiting were also more prevalent in the case of Bupivacaine, but separately none have had statistical significance. Nevertheless, the sum of adverse events was quite high with Bupivacaine (16 events; 53.33%) compared with Ropivacaine (7 events; 23.33) with a p-value of 0.036. This implies more safety profile of Ropivacaine with respect to fewer total side effects.

                          *Significant

The hemodynamic parameters of both groups are depicted in Table 4. The assessment hemodynamic parameters, including pulse rate, mean arterial pressure (MAP), and heart rate, were recorded at 1-, 30-, and 120-minute post-administration. No statistically significant differences were observed between the two groups across all time points, indicating comparable hemodynamic stability. Pulse rate remained within a similar range, as did MAP and heart rate. Although some variability existed, such as a slightly higher MAP at 1 minute in the Bupivacaine group (88.63 mmHg vs. 80.53 mmHg), none of these differences reached statistical significance. Thus, both 0.75% Ropivacaine and 0.5% Bupivacaine maintained stable cardiovascular profiles during epidural anesthesia for lower abdominal surgeries.

Epidural anesthesia remains an important method of regional anesthesia, particularly for lower abdominal and lower limb surgeries. It has several advantages as compared to spinal anesthesia which include better control of duration of surgery, lower incidence of hypotension, and better postoperative analgesia. However, the choice of a local anesthetic agent for epidural anesthesia is important because it determines the efficacy, duration, and safety of the block. Anesthetic agents like procaine are less potent and more effective agents such as Bupivacaine and Etidocaine offer stronger blockade but carry the risk of systemic toxicity. Bupivacaine although used commonly has been sometimes associated with serious cardiovascular complications including sudden cardiac collapse. To eliminate these disadvantages, a newer amino-amide local anesthetic, Ropivacaine was introduced. It structurally resembles Bupivacaine, but unlike bupivacaine, it is made up of a pure S (-) isomer rather than a racemic mixture. It has been demonstrated that such enantiomeric purity can decrease systemic toxicity (particularly cardiotoxicity) without decreasing effective anesthesia [9, 10]. The data on animal and nerve studies indicate its similar effectiveness and enhanced safety record. This was a randomized trial in which 60 patients who were having elective surgeries on the lower abdomen needed to be divided to ensure 30 of them received 20 ml of 0.75 % Ropivacaine in capsules and the other 30 received 0.5 % Bupivacaine in capsules epidurally. There were no significant differences between the two groups in the age and gender mix and this was in line with the results of Garaniya et al [11]. Sridevi et al. [2] Mahajan et al. [6] The onset of sensory blockade was significantly slower in the Ropivacaine group (2.26 ± 0.91 min) compared to the Bupivacaine group (1.86 ± 0.65 min; and p = 0.034). This is consistent with earlier reports by Kulkarni et al. [12] Mahajan et al. [6], Patel SJ, and Whiteside et al. [13] The delayed onset with Ropivacaine could be attributed to its lower lipophilicity, which influences its diffusion into nerve tissue. Similarly, motor block onset was slower with Ropivacaine (6.69 ± 0.98 min vs. 6.10 ± 0.94 min; and p = 0.022), as supported by Gaikwad et al. [14].

However, Bupivacaine demonstrated longer durations of both sensory and motor blockade compared to Ropivacaine (p < 0.005), indicating its superior potency in sustaining neural blockade. These findings are supported by studies from Brown et al. [7] and McGlade et al. [15]. The time to attain maximum sensory and motor block was also shorter with Bupivacaine. Despite this, Ropivacaine showed a significantly longer duration of analgesia, suggesting an advantage in postoperative pain management. Importantly, the incidence of adverse effects was lower in the Ropivacaine group. Although not statistically significant individually, the total number of adverse events was significantly lower with Ropivacaine (p = 0.036). Hypotension, bradycardia, shivering, and nausea/vomiting were all more frequent in the Bupivacaine group. These results reflect the findings of Garaniya et al. [11] and Kalbande et al. [16] reinforcing the improved safety profile of Ropivacaine. Hemodynamic parameters remained stable in both groups throughout the perioperative period, with no significant differences observed again supporting prior literature showing that both agents are hemodynamically stable [16, 17]. In summary, while Bupivacaine offers faster onset and longer blockade duration, Ropivacaine provides better hemodynamic stability, fewer adverse effects, and prolonged analgesia, making it a safer alternative in epidural anesthesia for lower abdominal surgeries.

In conclusion, based on the present clinical comparative study, we conclude that 0.75% Ropivacaine, when administered via the epidural route, provides adequate anesthesia for lower abdominal surgeries. 0.75% Ropivacaine had a short duration of motor block and prolonged duration of analgesia compared with 0.5% bupivacaine. The onset of sensory and motor blocks, hemodynamic changes, and side effect profile of Ropivacaine was not significantly different from that of bupivacaine. Hence, Ropivacaine can be used as a safe alternative to Bupivacaine for epidural anesthesia in lower abdominal surgeries. The short duration of motor block and prolonged duration of analgesia with Ropivacaine suggest that it could be effectively used for early mobilization of patients and better analgesia in the postoperative period.

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