European Journal of Cardiovascular Medicine

Post-operative pain control in children remains one of the most important yet challenging aspects of anesthetic management. Inadequately treated pain in early life can result in physiological stress responses, delayed wound healing, and long-term behavioral and psychological consequences such as anxiety or hyperalgesia [1]. Effective pain management therefore constitutes an ethical as well as clinical priority in pediatric anesthesia, requiring techniques that ensure adequate analgesia while minimizing systemic side-effects [2].

Regional anesthesia has become an integral component of multimodal peri-operative analgesia in children. The caudal epidural block, first introduced more than half a century ago, remains the most frequently employed regional technique for infra-umbilical procedures because of its reliability, simplicity, and safety [3]. It provides dense intra-operative analgesia and excellent post-operative comfort without significant hemodynamic instability when appropriately dosed [4].

Among long-acting amide local anesthetics, bupivacaine has traditionally been considered the gold standard because of its potent and prolonged sensory blockade. However, its association with cardiotoxicity and central nervous system toxicity has led to the development of safer S-enantiomer analogues—ropivacaine and levobupivacaine—which demonstrate similar efficacy with improved safety margins [5, 6]. These newer agents exhibit reduced lipid solubility and lower affinity for myocardial sodium channels, resulting in less motor blockade and reduced cardiotoxic potential [7].

Several randomized controlled trials have compared the analgesic efficacy of these drugs in pediatric populations with variable conclusions. Agarwal et al. (2019) found all three agents in 0.25 % concentration to be comparable in onset and duration of analgesia [1], whereas Unal et al. (2007) observed marginally faster recovery and lesser motor block with ropivacaine [2]. El-Bohigy et al. (2018) noted slightly longer duration of analgesia with bupivacaine but faster ambulation with ropivacaine and levobupivacaine [6]. These findings emphasize subtle yet clinically relevant differences in the pharmacodynamics of these agents.

Motor recovery is an important consideration in pediatric day-care surgeries where early mobilization and discharge are desirable. Breschan et al. (2005) demonstrated that ropivacaine produced less motor impairment and facilitated smoother recovery compared with bupivacaine [7]. Similarly, Ivani et al. (2002) confirmed that 0.2 % ropivacaine provided effective sensory blockade with minimal motor weakness [10]. Such properties make ropivacaine particularly useful when early ambulation is required.

Levobupivacaine, the S-enantiomer of bupivacaine, offers a promising compromise between potency and safety. Studies comparing levobupivacaine with ropivacaine suggest near-equivalent analgesic duration and superior hemodynamic stability [8, 9]. Its balanced profile has led to increasing preference in pediatric anesthesia where safety margins are paramount [5].

Recent literature also explores adjuvant drugs such as dexmedetomidine and clonidine to prolong caudal analgesia by synergistic α₂-adrenergic receptor action [4]. Although these agents enhance block duration, their routine use remains debated due to potential sedation or bradycardia. Thus, identifying the optimal base local anesthetic that ensures prolonged analgesia without adjuvants continues to be clinically relevant [3, 9].

Despite abundant international data, comparative evidence involving all three local anesthetics under standardized conditions within Indian tertiary-care pediatric populations remains limited. Variability in concentration, volume, and methodology across existing studies complicates interpretation [3, 5]. The present retrospective randomized controlled trial was therefore done  to compare 0.25 % ropivacaine, levobupivacaine, and bupivacaine for caudal analgesia in pediatric lower-abdominal surgeries, focusing on analgesic efficacy, safety, and overall parental satisfaction. By unifying methodology and objective pain scoring, this study aims to contribute definitive data to optimize pediatric regional anesthesia practice.

AIM

To compare the efficacy and safety of caudal ropivacaine, levobupivacaine, and bupivacaine in providing postoperative analgesia for pediatric patients undergoing elective lower abdominal surgeries at a tertiary care hospital.

OBJECTIVES

1.To evaluate and compare the duration of postoperative analgesia and pain intensity scores among the three local anesthetic agents—ropivacaine, levobupivacaine, and bupivacaine—administered via caudal epidural block in pediatric patients.

2. To assess and compare the incidence of adverse events, requirement for rescue analgesia, and parental satisfaction with postoperative pain control in each study group.

Study Design and Duration

A retrospective, randomized, controlled, double-blind clinical study was conducted over a period of two years, from January 2022 to December 2024, in the Department of Anesthesiology, at a tertiary care teaching hospital. The study was approved by the Institutional Ethics Committee, and written informed consent was obtained from the legal guardians of all participating children.

Study Population

Children aged 1–10 years, classified as ASA Physical Status I–II, operated for elective lower abdominal surgeries (such as herniotomy, orchidopexy, or urethroplasty) under general anesthesia with caudal analgesia, were enrolled.

Inclusion Criteria

• Pediatric patients aged 1–10 years.
• ASA grade I or II.
• Operated for elective infra-umbilical surgery under general anesthesia with planned caudal block.
• Informed parental consent obtained.

Exclusion Criteria

• Refusal of consent.
• Known hypersensitivity to amide local anesthetics.
• Coagulation disorders, spinal deformities, or local infection at the injection site.
• Pre-existing neurological or neuromuscular disease.

Randomization and Blinding

Participants were randomly grouped using a computer-generated randomization sequence into three equal groups:

• Group R: Ropivacaine 0.25 % (1 mL/kg)
• Group L: Levobupivacaine 0.25 % (1 mL/kg)
• Group B: Bupivacaine 0.25 % (1 mL/kg)

Drug solutions were prepared in identical syringes by an anesthesiologist not involved in data collection. Both the administering anesthesiologist and postoperative observers were blinded to group allocation.

Procedure

After induction of general anesthesia, patients were placed in the lateral decubitus position, and the caudal space was identified using anatomical landmarks under aseptic precautions. The allocated drug was injected slowly after confirming negative aspiration for blood or CSF. Standard intraoperative monitoring was maintained.

Outcome Measures

1. Primary Outcomes: Duration of postoperative analgesia (time from caudal injection to first rescue analgesic) and postoperative pain scores (FLACC / Wong–Baker scales).
2. Secondary Outcomes: Incidence of adverse effects (hypotension, bradycardia, urinary retention, nausea/vomiting), time to first rescue dose, total rescue analgesic requirement within 24 h, and parental satisfaction scores.

Statistical Analysis

Data were analyzed using SPSS version 21.0. Continuous variables were expressed as mean ± SD and analyzed by one-way ANOVA; categorical data were compared using the Chi-square test. A p-value < 0.05 was considered statistically significant.

Table 1. Baseline Demographic and Surgical Characteristics

Baseline characteristics such as age, gender, weight, and surgical duration were statistically comparable across all three groups (p > 0.05), confirming successful randomization and group homogeneity.

Table 2. Duration of Postoperative Analgesia

Although bupivacaine demonstrated the longest mean duration of analgesia (13.4 hours), the difference among groups was not statistically significant (p = 0.08). The sequence of efficacy remained Bupivacaine > Ropivacaine > Levobupivacaine.

Table 3. Postoperative Pain Scores (FLACC / Wong–Baker FACES)

Pain scores showed a consistent downward trend in all groups. Ropivacaine produced slightly lower scores in the early postoperative period (0–6 hours), suggesting better early pain control, although differences were not statistically significant.

Table 4. Time to First Rescue Analgesic and Number of Doses in 24 Hours

Patients receiving bupivacaine required their first rescue dose later and had slightly fewer analgesic doses in 24 hours. The pattern supports its longer analgesic profile compared to ropivacaine and levobupivacaine.

Table 5. Incidence of Adverse Events

The incidence of minor adverse events was low and comparable among all three groups (p > 0.05). No significant hemodynamic instability or severe complications occurred, confirming that all agents were safe for pediatric caudal administration.

Table 6. Parental Satisfaction Scores

Overall satisfaction with postoperative pain management was high across all groups. The highest satisfaction was reported in the bupivacaine and ropivacaine groups, consistent with their longer analgesic duration and better pain scores.

Analgesic efficacy: Comparable among all three local anesthetics, with bupivacaine showing a slight edge in duration.

1. Pain relief: Ropivacaine yielded marginally better early postoperative pain control.
2. Safety profile: No significant difference in adverse events; all drugs were well tolerated.
3. Clinical outcomes: High parental satisfaction and minimal need for rescue analgesics affirm that all three agents are effective for pediatric caudal analgesia.

Context and Clinical Significance

Postoperative pain control in pediatric surgical patients remains a cornerstone of enhanced recovery and patient satisfaction. Children experience variable pharmacodynamic responses to anesthetic drugs owing to differences in body composition, enzyme maturity, and pain perception. Among available regional techniques, the caudal epidural block continues to be the most accepted for infra-umbilical procedures because it provides uniform analgesia with a high safety margin when performed correctly. The current retrospective randomized controlled trial was undertaken to compare three long-acting amide local anesthetics—ropivacaine, levobupivacaine, and bupivacaine—with respect to postoperative analgesia duration, pain intensity trends, adverse event profile, and parental satisfaction in a homogeneous pediatric cohort. This study thereby addresses a relevant clinical question on optimizing postoperative comfort while minimizing motor blockade and systemic toxicity (11).

Pharmacologic Rationale and Methodological Uniformity

Bupivacaine, ropivacaine, and levobupivacaine possess closely related chemical structures but differ in optical configuration and lipid solubility, leading to distinct potency and toxicity profiles. Bupivacaine, a racemic mixture, offers excellent sensory block but is associated with a relatively prolonged motor blockade and potential cardiotoxicity. Ropivacaine and levobupivacaine, both S-enantiomers, demonstrate reduced cardiac and CNS toxicity due to lower affinity for sodium channels, while maintaining comparable sensory block characteristics. All agents in this study were used in equipotent concentrations (0.25%) with weight-based dosing to ensure pharmacologic equivalence. Caudal procedures were executed under strict asepsis, following a standardized lateral decubitus positioning, and all syringes were prepared in identical appearance to maintain blinding. The methodological rigor minimizes procedural bias and strengthens the validity of comparative outcomes (12).

Impact and Broader Clinical Implications

The results of this trial reinforce that each of these agents provides reliable postoperative analgesia for elective pediatric lower abdominal surgeries with minimal adverse effects. The slight prolongation in analgesia noted with bupivacaine (13.4 h) must be weighed against its greater tendency for motor block, whereas ropivacaine and levobupivacaine afford early recovery and ambulation. These findings support a balanced approach—selecting bupivacaine where prolonged immobility is acceptable and opting for ropivacaine/levobupivacaine in day-care or short-stay procedures. The incorporation of patient-guardian satisfaction as an endpoint adds a real-world dimension, underscoring how pharmacologic subtleties translate into experiential quality for both child and parent (13).

Duration of Postoperative Analgesia

In this study, the duration of effective analgesia followed the sequence Bupivacaine > Ropivacaine > Levobupivacaine, though the difference was not statistically significant (p = 0.08). This is consistent with Botla et al. (2024), who reported durations of 13.2 h, 12.5 h, and 11.8 h respectively (14). Locatelli et al. (2005) similarly found that bupivacaine lasted significantly longer than ropivacaine and levobupivacaine (p = 0.03) in 99 children (15). Cinar et al. (2015), studying infants, also observed longer block duration with bupivacaine (11.5 h vs 8.8 h; p = 0.004) (16). Conversely, Chipde et al. (2014) and Cyriac et al. (2022) found no significant difference at lower mean durations (≈ 4.5–5 h) (17, 18).
When dexmedetomidine was added as an adjuvant, the duration extended dramatically—as demonstrated by Bharti et al. (2014) (13 h with 1.5 µg/kg dexmedetomidine) and Anand et al. (2011) (14.5 h vs 5.5 h; p < 0.001) (19, 20). Imani et al. (2021) corroborated these effects (4.2 h vs 2.7 h; p = 0.001) (21). Collectively, these results affirm that caudal bupivacaine maintains the longest baseline analgesia, while adjuvants substantially enhance duration irrespective of agent used.

Pain Score Trends

Pain intensity assessed by FLACC and Wong–Baker FACES scales showed a uniform decline in all groups. Ropivacaine exhibited marginally lower early (0–6 h) scores—mirroring Chipde et al. (2014) and Botla et al. (2024), who noted smoother early-hour comfort with ropivacaine (17, 14). However, Cinar et al. (2015) observed significantly lower 1- and 3-hour OPS values with bupivacaine (p < 0.05), likely reflecting its higher lipid solubility in infants (16). In a broader context, Zhu et al. (2025) meta-analysis reported comparable 0.5-h pain scores between caudal and quadratus lumborum blocks but lower 4-h pain for QLB, suggesting technique selection may supersede agent choice in certain settings (22). Overall, early comfort appears marginally superior with ropivacaine, whereas bupivacaine maintains longer late-phase relief.

Rescue Analgesic Requirement

The mean time to first rescue analgesic was 13.3 h with bupivacaine, 12.8 h with ropivacaine, and 11.9 h with levobupivacaine, echoing Locatelli et al. (2005) and Botla et al. (2024), who documented a similar hierarchy (15, 14). Dexmedetomidine-augmented regimens reported by Bharti et al. (2014) and Anand et al. (2011) extended this interval up to 14–15 h, underscoring the adjuvant’s dose-dependent benefit (19, 20). The present data therefore reaffirm bupivacaine’s prolonged sensory blockade and demonstrate that rescue analgesic timing parallels analgesic duration trends across agents.

Adverse Events and Hemodynamic Stability

The current study observed a low incidence of minor adverse events—hypotension (8–10 %), bradycardia (≈ 5 %), and urinary retention (≈ 5 %)—with no statistically significant differences among groups (p > 0.05). These findings align closely with Botla et al. (2024) and Cinar et al. (2015), who reported equally minimal complication rates and no hemodynamic compromise (14, 16). Adjuvant studies by Imani et al. (2021) and Bharti et al. (2014) confirmed that dexmedetomidine addition did not increase adverse effects, apart from mild sedation at higher doses (21, 19). Furthermore, Zhu et al. (2025) found comparable adverse event rates between caudal and QLB techniques (10–12 %) (22). This cumulative evidence validates the excellent safety profile of all three local anesthetics for pediatric caudal use.

Parental Satisfaction and Clinical Outcomes

High satisfaction levels were recorded in all groups, with ≈ 65 % of parents rating “excellent.” Comparable satisfaction indices were reported by Cyriac et al. (2022) and Botla et al. (2024), reflecting parallel analgesic efficacy and tolerability (18, 14). Although older studies rarely included satisfaction endpoints, newer investigations such as Anand et al. (2011) emphasized better emergence behavior and calmer recovery with dexmedetomidine-enhanced ropivacaine (20). The current findings therefore affirm that patient-guardian satisfaction is high across agents and correlates primarily with adequate pain relief and minimal postoperative agitation.

Integrated Evidence Synthesis

Across multiple trials, caudal bupivacaine consistently yields the longest analgesic duration but with slightly increased motor block potential. Ropivacaine and levobupivacaine offer nearly equivalent sensory efficacy with reduced toxicity, enabling faster ambulation. The present results align closely with pooled data from major comparative studies (14–18) and reinforce the pharmacologic principle that S-enantiomers provide safer sensory-selective blockade. When adjuvants such as dexmedetomidine are used, the distinction between agents becomes less clinically relevant, as duration and comfort are markedly enhanced without safety compromise (19–21). These converging outcomes strengthen the external validity of our findings and support individualized agent selection based on surgical duration, recovery goals, and institutional protocols.

Table 7. Comparison of Analgesia Duration Across Studies

Table 8. Postoperative Pain Score Trends Across Studies

Table 9. Time to First Rescue Analgesia and Analgesic Use

Table 10. Incidence of Adverse Events in Comparative Studies

Table 11. Parental Satisfaction and Recovery Outcomes

The current study demonstrates that ropivacaine, levobupivacaine, and bupivacaine each provide effective and safe postoperative analgesia in pediatric lower abdominal surgeries performed under caudal block. Although bupivacaine offers a marginally longer duration of analgesia, ropivacaine ensures smoother early recovery and minimal motor blockade, while levobupivacaine represents an equally safe and efficacious intermediate option. The results affirm the suitability of all three agents for routine pediatric caudal analgesia, with agent selection tailored to clinical priorities.

Limitations

1. The study was single-center with a modest sample size (n = 113), which may limit generalizability.
2. Pain assessment relied on observer-dependent scales (FLACC, Wong–Baker), introducing potential subjectivity.
3. Serum drug concentrations were not measured, precluding pharmacokinetic correlation.
4. Long-term neurobehavioral outcomes and motor recovery times were not included.

Future Directions

Future multicenter trials with larger samples, objective pain monitoring, and pharmacokinetic evaluation are recommended. Comparative assessments incorporating ultrasound-guided techniques, adjuvants, and multimodal analgesic protocols would further refine pediatric regional anesthesia strategies. Studies exploring neurotoxicity biomarkers and long-term sensory outcomes could enhance mechanistic understanding and safety assurance.

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