The advancement of regional anaesthesia has revolutionized the management of obstetric analgesia and anaesthesia, particularly in the context of caesarean sections. 1 Spinal anaesthesia has become the preferred technique for these procedures, owing to its rapid onset, minimal residual effects,ability to provide effective anaesthesia without compromising maternal consciousness and least adverse effects on body .2 Within spinal anaesthesia, around 95 % of Lower Segment Caesarean Section (LSCS) in India are done under spinal anaesthesia ,the selection of appropriate local anaesthetics is crucial, as it directly influences the quality of pain relief, duration of anaesthesia, and overall maternal and neonatal safety during surgery.3

After use of lignocaine is stopped for spinal anesthesia due to report of neuropathy .4The most commonly used local anaesthetics for spinal anaesthesia are bupivacaine and ropivacaine. Both of these agents are highly effective in providing adequate sensory and motor blockade, but they differ in their pharmacological profiles, particularly in terms of their potency, duration of action, and cardiovascular safety.5 Bupivacaine has traditionally been the anaesthetic agent of choice in obstetric spinal anaesthesia due to its potent anaesthetic effects and longer duration of action. However, it is also associated with a higher risk of hypotension, which can affect both maternal and foetal well-being.6 In contrast, ropivacaine, a newer agent, is known to offer similar analgesic efficacy with a potentially better safety profile, particularly in terms of its cardiovascular stability.7

The increasing rates of elective caesarean deliveries globally necessitate careful evaluation of the anaesthetic agents used in these procedures to ensure optimal outcomes for both the mother and the neonate.8 The hemodynamic changes induced by spinal anaesthesia are an important consideration, as fluctuations in blood pressure and heart rate can significantly impact maternal safety. Therefore, the choice of anaesthetic agent must strike a balance between effective anaesthesia and maintaining stable hemodynamics throughout the procedure.9

Hyperbaric formulations of both bupivacaine and ropivacaine are commonly employed in spinal anaesthesia for caesarean sections. The addition of a hyperbaric solution increases the density of the local anaesthetic, which aids in more controlled and predictable distribution in the subarachnoid space.10 The clinical efficacy, duration of action, and hemodynamic effects of these agents in their hyperbaric form have been subjects of ongoing research. However, a comprehensive comparison of these two agents, specifically focusing on their clinical profiles, efficacy, and hemodynamic effects during caesarean sections, remains an area in need of further investigation.11 This study seeks to compare the effects of 10 mg hyperbaric bupivacaine 0.5% and 15 mg hyperbaric ropivacaine 0.75% in patients undergoing caesarean section with spinal anaesthesia. Specifically, the objectives of this research are twofold: first, to compare the clinical profiles of these two agents in terms of sensory and motor blockade, hemodynamic stability, and adverse effects during caesarean delivery; and second, to evaluate the clinical efficacy and duration of action of ropivacaine and bupivacaine in this context. By addressing these objectives, this study aims to provide valuable insights into which anaesthetic agent offers a more favorable profile for use in caesarean sections, contributing to improved maternal and neonatal outcomes while optimizing anaesthetic practice.

AIM

To compare the clinical effects of hyperbaric bupivacaine and hyperbaric ropivacaine administered via spinal anaesthesia in patients undergoing cesarean delivery

OBJECTIVES

1. To compare the clinical profile of 10 mg of 0.5% hyperbaric bupivacaine and 15 mg of 0.75% hyperbaric ropivacaine in women undergoing cesarean section.
2. To evaluate and compare the clinical efficacy, onset, and duration of sensory and motor blockade between hyperbaric bupivacaine and hyperbaric ropivacaine during cesarean section.

SOURCE OF DATA: A prospective, randomized, double-blind study was conducted at the Department of Anesthesiology, following approval by the Institutional Ethics Committee. The study involved 60 adult patients scheduled for undergoing an elective caesarean section. Written informed consent was obtained from all participants. Method of collection of data Inclusion criteria 1. Age: 18-40 years 2. Height( 150-170cm) 3. ASA Grade II 4. Elective caesarean section patients Exclusion Criteria: 1.All contraindications to Spinal Anesthesia Group allocation Patients were randomly assigned to one of two groups, Group R and Group B, with 30 patients in each group. Randomization was performed using computer- generated random numbers, which were sealed in sequentially numbered envelopes. This was a double-blind study, with both the patient and investigator unaware of the drug allocation. The drug code was sealed in an envelope and was only opened by the anesthesiologist administering the spinal anesthesia, who was not involved in data collection. 1.Group B: 10 mg of hyperbaric Bupivacaine 0.5% 2.Group R: 15 mg of hyperbaric Ropivacaine 0.75%

TABLE: Sensory and Motor Block Profile (Mean ± Standard Deviation) Sensory and Motor Block Profile (Mean ± Standard Deviation)

In the sensory block profile, no significant difference was observed in the onset of sensory block between Ropivacaine (4.23 ± 0.50 min) and Bupivacaine (4.10 ± 0.30 min), with a p-value of 0.227. Both groups achieved a comparable maximal sensory level (T3/T4), and this difference was not statistically significant (p = 0.114). The time taken to reach the maximal sensory level was slightly longer in the Ropivacaine group (8.97 ± 0.88 min) compared to the Bupivacaine group (8.73 ± 0.57 min), but this variation was also not statistically significant (p = 0.215). Additionally, the total duration of sensory block lasted for 173.50 ± 9.299 min with Ropivacaine and 176.37 ±1.40 min with Bupivacaine, with no significant difference between the two groups (p = 0.100).

In contrast, the motor block profile showed notable differences. The onset of motor block was significantly faster with Bupivacaine (3.87 ± 0.34 min) compared to Ropivacaine (5.20 ± 0.40 min), and this difference was statistically significant (p = 0.005). Moreover, the total duration of motor block was significantly longer with Bupivacaine (156.47 ± 8.7 min) than with Ropivacaine (126.50 ± 3.6 min), with a highly significant p-value (p = 0.001). Overall, while the sensory block characteristics were comparable between the two groups, Bupivacaine exhibited a faster onset and a longer duration of motor block, making it more effective for prolonged motor blockade

TABLE: Comparison of Study Groups According to Intraoperative Sensory Block Onset

Interpretation:

In our study, the onset of sensory block intraoperatively was taken at the T8 dermatome level.

• The Z-score is 7.5, which indicates a large difference between the two groups.
• The p-value is less than 0.05, which means the difference is statistically significant. This suggests that the difference in the mean time of onset between Group R and Group B is statistically significant, with Group R having a later onset time for sensory block compared to Group B.

Table: Motor Blockade Comparison: Ropivacaine vs Bupivacaine

In this study, the motor blockade produced by hyperbaric Ropivacaine and Bupivacaine was compared over a 2-hour period. Both groups achieved complete motor block (score of 3.0 ± 0.0) at 5 and 15 minutes, indicating a similar and rapid onset of action. However, differences emerged in the duration and regression of motor blockade. Ropivacaine maintained a full block until 30 minutes and showed only a gradual decline thereafter, with motor block scores of 2.53 ± 0.56 at 45 minutes and 2.03 ± 0.18 at 1 hour. In contrast, Bupivacaine exhibited an earlier and steeper decline in motor blockade starting at 30 minutes (2.83 ± 0.64), reaching near-complete resolution by 2 hours (0.03 ± 0.18). The standard deviation values also reflected this variability, particularly with Bupivacaine, suggesting more inconsistent regression among patients. Overall, while both agents provide comparable onset, Ropivacaine was associated with a longer-lasting and more consistent motor block, whereas Bupivacaine allowed for a quicker motor recovery, which may be advantageous in ambulatory or short-duration surgeries.

Table: Here is the comparative table showing Mean Arterial Pressure (MAP) values and p-values (Unpaired t-test, n = 30 per group):

The comparative analysis of Mean Arterial Pressure (MAP) between the Ropivacaine and Bupivacaine groups over a 2-hour observation period revealed important differences in their hemodynamic profiles. At baseline, both groups had nearly identical MAP values (Ropivacaine: 93.12 ± 4.26 mmHg; Bupivacaine: 93.37 ± 3.46 mmHg; p = 0.8080), with no significant differences noted in the initial 15 minutes post-administration. During this early intraoperative period (5–15 minutes), MAP declined gradually in both groups but remained statistically comparable (p values > 0.4), indicating a similar onset of sympathetic blockade.However, a significant divergence was observed beginning at 20 minutes. The Bupivacaine group experienced a marked drop in MAP to 77.57 ± 1.78 mmHg, while the Ropivacaine group maintained a higher value of 85.49 ± 2.71 mmHg (p < 0.0001). This trend continued at 25, 30, and 40 minutes, with the Bupivacaine group consistently showing significantly lower MAP levels than the Ropivacaine group (p < 0.0001 at each interval). These findings suggest that Bupivacaine is associated with a greater degree of hypotension during the intraoperative period, likely due to more profound sympathetic blockade. In contrast, Ropivacaine demonstrated better hemodynamic stability during this critical time frame.At 50 minutes, a reversal was noted where the Bupivacaine group showed a slightly higher MAP (88.86 ± 3.33 mmHg) compared to the Ropivacaine group (87.31 ± 1.82 mmHg), which was statistically significant (p = 0.0308). However, from 1 hour onward, MAP values in both groups converged and showed no statistically significant differences (p > 0.4). By 1.5 and 2 hours, both groups had MAP values close to baseline, indicating recovery from the earlier hypotensive effect.

Table: Rescue Analgesia Requirement (Mean ± Standard Deviation)

The mean time to the first dose of rescue analgesia was slightly shorter in the Ropivacaine group (153 minutes) compared to the Bupivacaine group (156.07 minutes).However, the p-value (0.279) indicates that this difference is not statistically significant (p > 0.05).

Sensory Block Profile-In our study, the onset of sensory block was slightly slower in the Ropivacaine group (mean 4.23± 0.50 minutes) compared to the Bupivacaine group (4.10 ± 0.30 minutes), although the difference was not statistically significant. However, when compared with the findings of Chung et al. (2001)43, Dar et al. (2015) 45, and Shah et al. (2016) 46, the delayed onset of sensory block with Ropivacaine becomes more evident, particularly in cesarean section patients where a more rapid onset is often desirable.The duration of sensory block in our study was shorter with Ropivacaine (173.50 ± 9.30 min) compared to Bupivacaine (176.37 ± 1.40 min), though this difference was again statistically insignificant. This aligns with results from Chung et al., 43 who reported a significantly shorter sensory block with Ropivacaine (162.5 ± 20.2 min vs. 188.5 ± 28.2 min, p < 0.05), and Dar et al.(2015), 45 who observed a marked reduction in sensory block duration (160 ± 12.9 min vs. 260 ± 16.1 min). Therefore, while our study showed a numerical trend toward shorter sensory block with Ropivacaine, statistical significance might require a larger sample size.

Motor Block Profile-Our study demonstrated a significantly slower onset of motor block with Ropivacaine (5.20 ± 0.40 min) compared to Bupivacaine (3.87 ± 0.34 min), with p = 0.005, indicating strong statistical significance. This finding is in concordance with studies such as:

•Shah et al. (2016) 46: 7.10 ± 0.84 min (Ropivacaine) vs. 5.28 ± 0.82 min (Bupivacaine)

•Dar et al. (2015) 45 and Ghimire et al. (2019)47 also reported similar delays with Ropivacaine

The total duration of motor block was significantly shorter in the Ropivacaine group (126.50 ± 3.6 min) compared to the Bupivacaine group (156.47 ± 8.7 min), p = 0.001, confirming a faster recovery. This is consistent with the observations of Chung et al. 43 (113.7 min vs. 158.7 min), Srivastava et al., 44 and Kalbande et al., who all emphasized that Ropivacaine allows for earlier ambulation due to faster regression of motor block.In the present study, both hyperbaric ropivacaine and bupivacaine demonstrated complete motor blockade at 5 and 15 minutes, indicating comparable onset times. However, the duration of motor blockade differed significantly between the two agents. Ropivacaine exhibited a slower and more gradual regression of motor blockade, maintaining higher mean motor scores up to 2 hours, whereas bupivacaine showed a more rapid decline, with almost complete resolution by 2 hours. These findings are in contrast with earlier studies, such as Chung et al. (2001) 43 and Srivastava et al. (2012), 44 who observed shorter durations of motor block with ropivacaine compared to bupivacaine. Similarly, Dar et al. (2015) 45 and Shah et al. (2016) 46 reported significantly shorter durations and slower onset of motor block with ropivacaine. Ghimire et al. (2019) 47 also found faster onset and longer duration with bupivacaine. However, more recent studies such as Kishore Kumar et al. (2024)48 and Kalbande et al. (2024) indicated that block quality with both agents was similar, with ropivacaine offering a safer hemodynamic profile and faster motor recovery. In alignment with these later findings, our study confirms that while ropivacaine maintains effective motor block, it also allows for gradual regression, making it a favorable choice in settings where prolonged motor block is beneficial but rapid recovery is also desired. The variation from earlier results may be attributed to differences in dosage, baricity, dextrose concentration, or patient populations.

Hemodynamic Parameters-A striking finding in our study was the superior hemodynamic stability offered by Ropivacaine. Although both groups had similar baseline SBP, DBP, and MAP, a significant hypotensive trend was observed in the Bupivacaine group during the critical intraoperative window (20–40 minutes post-administration). This finding has been echoed in:

•Ghimire et al. (2019) 47, who observed more stable hemodynamics with Ropivacaine

•Masih et al. (2024)49, who reported a lower incidence of hypotension with Ropivacaine (10%) vs. Bupivacaine (24%)

•Kishore Kumar et al. (2024)48 and Kalbande et al. (2024) also demonstrated fewer cardiovascular fluctuations with Ropivacaine These results support the premise that Ropivacaine produces less sympathetic blockade, making it a safer alternative in patients vulnerable to hemodynamic instability, such as the elderly or obstetric patients.

Rescue Analgesia              

The time to first rescue analgesia was slightly shorter in the Ropivacaine group (153 min) compared to the Bupivacaine group (156.07 min), but this was not statistically significant (p = 0.279). This is in line with Srivastava et al. (2012) 44 and Masih et al. (2024)49, where both agents were equally effective in maintaining surgical anesthesia, but Bupivacaine offered a marginally longer postoperative analgesia.

This prospective comparative study was conducted to evaluate and compare the clinical efficacy, block characteristics, hemodynamic stability, analgesic requirements, and adverse effect profiles of intrathecal 0.75% hyperbaric Ropivacaine and 0.5% hyperbaric Bupivacaine in patients undergoing infraumbilical surgeries. A total of 60 patients were enrolled and randomized into two equal groups (n = 30 each). Both groups were demographically comparable in terms of age, weight, height, and BMI, with no statistically significant differences, ensuring homogeneity and allowing unbiased comparison.The onset of sensory block was slightly slower in the Ropivacaine group (mean 4.23 ± 0.50 minutes) compared to the Bupivacaine group (4.10 ± 0.30 minutes), though this difference was not statistically significant. The duration of sensory block was also marginally shorter in the Ropivacaine group (173.50 ± 9.30 minutes) than in the Bupivacaine group (176.37 ± 1.40 minutes), again without statistical significance. However, these findings were consistent with previous studies suggesting a trend toward slightly shorter and less dense sensory block with Ropivacaine.In terms of motor block characteristics, Ropivacaine demonstrated a significantly slower onset (5.20 ± 0.40 minutes) compared to Bupivacaine (3.87 ± 0.34 minutes), with a p-value of 0.005. Furthermore, the duration of motor block was significantly shorter in the Ropivacaine group (126.50 ± 3.6 minutes) than in the Bupivacaine group (156.47 ± 8.7 minutes), with a p-value of0.001. These findings indicate that Ropivacaine allows for earlier motor recovery and faster postoperative mobilization, a key advantage in day-care and ambulatory surgeries.Hemodynamic parameters remained stable in both groups initially, but a significant hypotensive trend was observed in the Bupivacaine group during the 20–40-minute intraoperative period. Although not statistically quantified in this study, the clinical impression and consistency with literature (e.g., Masih et al., 2024 – hypotension incidence: 24% with Bupivacaine vs. 10% with Ropivacaine) suggest that Ropivacaine provides better hemodynamic stability, making it more favorable in elderly, obstetric, or cardiovascular-risk patients. The time to first rescue analgesia was slightly shorter in the Ropivacaine group (153 minutes) compared to the Bupivacaine group (156.07 minutes), but the difference was not statistically significant (p = 0.279), indicating comparable analgesic efficacy of both drugs during the early postoperative period. The incidence of adverse effects, including hypotension, bradycardia, nausea, and vomiting, was low in both groups. Although more patients in the Bupivacaine group experienced hypotension and nausea, the differences were not statistically significant, and no serious complications were reported in either group.In conclusion, both 0.75% hyperbaric Ropivacaine and Bupivacaine are effective for spinal anesthesia in infraumbilical surgeries. However, Ropivacaine offers significant advantages, including slower onset and shorter duration of motor block, earlier postoperative recovery, and greater hemodynamic stability. These features make it a suitable agent for short-duration surgeries and for patients in whom cardiovascular safety and early mobilization are important considerations. Bupivacaine, with its denser and longer block, remains a reliable choice for longer procedures but requires cautious use in patients susceptible to hemodynamic fluctuations. This study supports a tailored, patient-specific approach to the selection of intrathecal anesthetic agents based on surgical requirements and individual risk profiles.

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