Spinal anaesthesia is the anaesthetic technique of choice for most caesarean sections because it provides rapid onset, dense sensory and motor blockade, excellent operating conditions, minimal fetal drug exposure, and allows the mother to remain awake during childbirth. Compared with general anaesthesia, it is associated with lower maternal morbidity, avoidance of difficult airway management and aspiration, improved postoperative analgesia, and earlier maternal–neonatal bonding.¹–³ Despite these advantages, maternal hypotension remains the most frequent complication following spinal anaesthesia for caesarean section, with a reported incidence ranging from 50% to 80% in the absence of preventive measures.⁴⁻⁷ Sympathetic blockade results in arterial and venous vasodilatation, reduced systemic vascular resistance, diminished venous return, and decreased cardiac output. Pregnancy-related physiological changes, including aortocaval compression by the gravid uterus and increased dependence on sympathetic tone, further predispose parturients to hypotension. Clinically significant hypotension may cause maternal nausea, vomiting, dizziness, and altered consciousness, while prolonged reductions in uteroplacental perfusion may adversely affect fetal oxygenation.⁵⁻⁹ Consequently, maintaining maternal haemodynamic stability remains a major objective during obstetric spinal anaesthesia. Hyperbaric bupivacaine is the most commonly used intrathecal local anaesthetic for caesarean delivery because it provides reliable surgical anaesthesia with a predictable onset and duration of action. However, its extensive sympathetic blockade is associated with a relatively high incidence of hypotension and vasopressor requirement.⁴⁻⁸ Although fluid loading, left uterine displacement, and prophylactic vasopressors reduce the severity of hypotension, they do not eliminate it completely, prompting continued evaluation of alternative local anaesthetic agents. Levobupivacaine, the pure S(-)-enantiomer of bupivacaine, was developed to reduce the cardiovascular and central nervous system toxicity associated with racemic bupivacaine while maintaining comparable anaesthetic efficacy.¹⁰⁻¹² Owing to its lower affinity for myocardial sodium channels, levobupivacaine demonstrates a more favourable cardiovascular safety profile and has been shown to produce effective neuraxial blockade with less cardiotoxicity in experimental and clinical studies.¹⁰⁻¹² Several comparative studies have evaluated intrathecal levobupivacaine for caesarean section and have reported satisfactory sensory and motor blockade with improved haemodynamic stability compared with bupivacaine.¹³⁻²⁰ However, the available literature remains heterogeneous with respect to drug baricity, intrathecal dose, study design, and outcome measures. Furthermore, evidence from Indian obstetric populations evaluating hyperbaric levobupivacaine remains limited. The present prospective randomized comparative study was therefore undertaken to compare the maternal haemodynamic effects of intrathecal hyperbaric levobupivacaine (0.5%) and hyperbaric bupivacaine (0.5%) in women undergoing caesarean section under spinal anaesthesia. The primary objective was to compare serial changes in systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate following spinal anaesthesia. Secondary objectives included comparison of the incidence and severity of hypotension, bradycardia, vasopressor requirement, glycopyrrolate administration, and intravenous fluid bolus requirement between the two study groups.

Study Design and Setting This prospective, randomized, comparative, open-label study was conducted in the Department of Anaesthesiology, Government Medical College and Maharashtra Post Graduate Institute of Medical Education and Research (GMC & MPGIMER), Nashik, Maharashtra, India, after obtaining approval from the Institutional Ethics Committee. The study was conducted over a period of 18 months. Written informed consent was obtained from all participants before enrolment. Study Population A total of 200 pregnant women scheduled to undergo elective or emergency lower segment caesarean section (LSCS) under spinal anaesthesia were included in the study. Eligible participants were aged 18–40 years and belonged to American Society of Anesthesiologists (ASA) physical status II. Inclusion Criteria • Pregnant women aged 18–40 years. • Singleton term pregnancy. • Elective or emergency LSCS under spinal anaesthesia. • ASA physical status II. • Provision of written informed consent. Exclusion Criteria Patients with any of the following were excluded: • Refusal to participate. • Contraindications to spinal anaesthesia. • Known hypersensitivity to amide local anaesthetics. • Pregnancy-induced hypertension, eclampsia, or severe pre-eclampsia. • Significant cardiovascular, hepatic, renal, or neurological disease. • Coagulation disorders or anticoagulant therapy. • Local infection at the puncture site. • Multiple pregnancy. • Body mass index >35 kg/m². Randomization Participants were randomly allocated into two equal groups (n = 100 each) using sealed opaque envelopes. • Group LH: Received 10 mg (2 mL) of 0.5% hyperbaric levobupivacaine intrathecally. • Group BH: Received 10 mg (2 mL) of 0.5% hyperbaric bupivacaine intrathecally. Anaesthetic Technique All patients underwent standard pre-anaesthetic evaluation. On arrival in the operating theatre, an 18-gauge intravenous cannula was secured and routine monitoring, including electrocardiography (ECG), non-invasive blood pressure (NIBP), pulse oximetry (SpO₂), and heart rate (HR), was instituted. Patients received intravenous crystalloid preload according to the study protocol. Under strict aseptic precautions, spinal anaesthesia was administered in the sitting position at the L3–L4 or L4–L5 intervertebral space using a 25-gauge Quincke spinal needle. Following confirmation of free cerebrospinal fluid flow, the allocated study drug was injected intrathecally over approximately 10–15 seconds. Patients were immediately positioned supine with left uterine displacement, and supplemental oxygen was administered via face mask throughout surgery. Outcome Measures Primary Outcome Maternal haemodynamic stability assessed by serial measurements of: • Systolic blood pressure (SBP) • Diastolic blood pressure (DBP) • Mean arterial pressure (MAP) • Heart rate (HR) • Haemodynamic parameters were recorded at: • Baseline (before spinal anaesthesia) • Immediately after intrathecal injection (0 minute) • 1, 2, 3, 4, 5, 10, 15, 20, 30, and 45 minutes • End of surgery Secondary Outcomes The following outcomes were compared between the two groups: • Incidence of hypotension. • Severity of hypotension. • Incidence of bradycardia. • Vasopressor requirement. • Glycopyrrolate administration. • Intravenous fluid bolus requirement. Definitions • Hypotension: Systolic blood pressure <90 mmHg or a decrease of >20% from baseline. • Bradycardia: Heart rate <60 beats/min. • Hypotension and bradycardia were managed according to the institutional protocol using standard rescue medications. Statistical Analysis Data were entered into Microsoft Excel and analysed using SPSS software. Continuous variables were expressed as mean ± standard deviation (SD), while categorical variables were expressed as frequencies and percentages. Continuous variables were compared using the independent Student's t-test, whereas categorical variables were analysed using the Chi-square test or Fisher's exact test, as appropriate. A two-tailed P value <0.05 was considered statistically significant.

Patient Characteristics A total of 200 parturients were enrolled in the study and randomly allocated into two equal groups: Group LH (hyperbaric levobupivacaine, n=100) and Group BH (hyperbaric bupivacaine, n=100). All participants completed the study and were included in the final analysis. There were no statistically significant differences between the two groups regarding age, weight, height, body mass index, gestational age, gravida, parity, ASA physical status, or type of caesarean section (P>0.05), indicating that both groups were comparable at baseline . TABLE 1 Age group (years) Group LH (n=100) Group BH (n=100) Total (n=200) p-value 18–20 8 10 18 0.812 21–25 34 32 66 26–30 38 36 74 31–35 15 17 32 36–40 5 5 10 Mean age (years) 27.84 ± 4.36 27.62 ± 4.58 27.73 ± 4.47 Baseline Haemodynamic Parameters Baseline haemodynamic variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and peripheral oxygen saturation (SpO₂) were comparable between the two groups with no statistically significant differences (P>0.05) TABLE 2 Parameter Group LH (n=100) Group BH (n=100) p-value SBP (mmHg) 124.86 ± 11.92 123.94 ± 12.14 0.621 DBP (mmHg) 72.36 ± 9.84 71.88 ± 9.65 0.744 MAP (mmHg) 89.86 ± 9.62 89.23 ± 9.48 0.658 HR (bpm) 89.64 ± 12.39 90.94 ± 10.05 0.415 SpO₂ (%) 99.12 ± 0.74 99.08 ± 0.81 0.716 Serial Changes in Systolic Blood Pressure Following intrathecal administration, systolic blood pressure decreased in both groups. However, the decline was significantly greater in the hyperbaric bupivacaine group. Statistically significant differences were observed immediately after spinal anaesthesia and at 1, 2, 3, 4, 5, 10, 20, 30 and 45 minutes, as well as at the end of surgery (P<0.05). No significant difference was observed at 15 minutes (P=0.054). Patients receiving hyperbaric levobupivacaine maintained significantly higher systolic blood pressure throughout the intraoperative period . TABLE 3. Time Group LH (mmHg) Group BH (mmHg) p-value Basal 124.86 ± 11.92 123.94 ± 12.14 0.621 After spinal 120.80 ± 10.57 112.75 ± 15.16 <0.001 1 min 118.11 ± 11.25 104.29 ± 12.59 <0.001 2 min 116.99 ± 15.19 109.16 ± 15.25 <0.001 3 min 115.22 ± 14.62 103.87 ± 20.24 <0.001 4 min 112.15 ± 16.87 105.03 ± 22.92 0.012 5 min 116.86 ± 21.94 102.25 ± 21.39 <0.001 10 min 112.62 ± 18.11 101.03 ± 22.12 <0.001 15 min 110.64 ± 20.41 104.63 ± 23.52 0.054 20 min 112.38 ± 13.48 107.56 ± 14.99 0.017 30 min 115.93 ± 13.66 110.25 ± 14.86 0.005 45 min 116.94 ± 13.65 112.25 ± 16.48 0.028 End 122.78 ± 9.80 116.74 ± 11.26 <0.001 Serial Changes in Diastolic Blood Pressure Diastolic blood pressure decreased after spinal anaesthesia in both groups. The reduction was significantly greater in the hyperbaric bupivacaine group during the early intraoperative period, particularly between 0 and 10 minutes. Thereafter, DBP gradually recovered and became comparable between the two groups. TABLE 4. Time Group LH (mmHg) Group BH (mmHg) p-value Basal 72.36 ± 9.84 71.88 ± 9.65 0.744 After spinal 70.64 ± 12.12 62.20 ± 15.14 <0.001 1 min 68.34 ± 12.32 65.45 ± 13.68 0.116 2 min 65.78 ± 14.28 63.92 ± 15.58 0.379 3 min 66.84 ± 13.48 63.48 ± 12.48 0.067 4 min 62.53 ± 11.25 55.23 ± 18.73 <0.001 5 min 64.96 ± 13.51 54.44 ± 16.88 <0.001 10 min 63.64 ± 13.37 57.73 ± 19.14 0.011 15 min 62.34 ± 13.77 59.94 ± 15.64 0.249 20 min 61.95 ± 12.89 63.87 ± 13.57 0.305 30 min 63.19 ± 10.32 65.36 ± 18.77 0.311 45 min 65.99 ± 10.83 63.66 ± 18.97 0.286 End 67.28 ± 12.03 65.88 ± 17.75 0.514 Serial Changes in Mean Arterial Pressure Mean arterial pressure demonstrated a pattern similar to systolic blood pressure. MAP declined following spinal anaesthesia in both groups, with a significantly greater reduction in Group BH during the first 10 minutes. After 15 minutes, MAP gradually approached baseline values, and intergroup differences were no longer statistically significant TABLE 5. Time Group LH (mmHg) Group BH (mmHg) p-value Basal 89.86 ± 9.62 89.23 ± 9.48 0.658 After spinal 87.36 ± 8.00 79.00 ± 15.14 <0.001 1 min 84.93 ± 5.95 78.40 ± 13.04 <0.001 2 min 82.85 ± 7.22 79.00 ± 15.30 0.023 3 min 82.97 ± 6.76 76.94 ± 18.87 0.003 4 min 79.07 ± 5.21 72.08 ± 20.43 <0.001 5 min 82.26 ± 7.90 71.71 ± 18.45 <0.001 10 min 79.97 ± 6.02 72.16 ± 20.76 <0.001 15 min 78.44 ± 5.12 74.84 ± 18.76 0.064 20 min 78.76 ± 6.52 78.43 ± 14.04 0.831 30 min 80.77 ± 7.00 80.32 ± 16.93 0.806 45 min 82.97 ± 4.99 79.86 ± 17.37 0.085 End 85.78 ± 7.45 82.82 ± 15.77 0.090 Serial Changes in Heart Rate Heart rate remained relatively stable in both groups throughout surgery. A transient statistically significant difference was observed at four minutes after spinal anaesthesia (P=0.025), whereas all remaining time points showed comparable heart rate values between the groups. TABLE 6. Time Group LH (bpm) Group BH (bpm) p-value Basal 89.64 ± 12.39 90.94 ± 10.05 0.415 After spinal anaesthesia 96.24 ± 14.18 99.26 ± 13.12 0.118 1 min 97.52 ± 15.58 96.42 ± 16.29 0.626 2 min 95.93 ± 12.39 92.13 ± 16.78 0.068 3 min 95.32 ± 18.46 99.39 ± 22.49 0.162 4 min 93.65 ± 17.45 99.81 ± 21.32 0.025 5 min 95.31 ± 19.41 99.03 ± 20.84 0.191 10 min 95.64 ± 13.69 96.54 ± 16.66 0.676 15 min 94.26 ± 13.99 95.15 ± 16.56 0.681 20 min 92.97 ± 12.65 95.28 ± 16.14 0.260 30 min 93.84 ± 14.52 94.38 ± 13.65 0.786 45 min 92.84 ± 14.12 93.38 ± 12.65 0.776 End of surgery 81.34 ± 13.78 83.65 ± 9.42 0.166 Haemodynamic Complications The incidence of haemodynamic complications was significantly lower in the hyperbaric levobupivacaine group (Table 7). Maternal hypotension occurred in 28% of patients in Group LH compared with 61% in Group BH (P<0.001). Bradycardia was also significantly less frequent in Group LH than in Group BH (12% vs. 29%; P=0.003). Patients receiving hyperbaric levobupivacaine required significantly fewer therapeutic interventions. Vasopressor administration was required in 24% of patients in Group LH compared with 55% in Group BH (P<0.001). Glycopyrrolate administration (10% vs. 24%; P=0.008) and intravenous fluid bolus requirement (31% vs. 58%; P<0.001) were also significantly lower in Group LH. Severity of Hypotension The severity of hypotension differed significantly between the study groups (Table 8). Most patients receiving hyperbaric levobupivacaine (72%) maintained normal blood pressure throughout surgery compared with only 39% of patients receiving hyperbaric bupivacaine. Mild hypotension occurred in 18% and 24% of patients in Groups LH and BH, respectively. Moderate hypotension was observed in 8% of patients in Group LH compared with 27% in Group BH, while severe hypotension occurred in 2% and 10% of patients, respectively (P<0.001). Overall Findings Hyperbaric levobupivacaine demonstrated superior maternal haemodynamic stability compared with hyperbaric bupivacaine. Patients receiving levobupivacaine showed better preservation of systolic, diastolic and mean arterial pressures, significantly lower incidences of hypotension and bradycardia, and reduced requirements for vasopressors, glycopyrrolate and intravenous fluid boluses.

The present prospective randomized comparative study evaluated maternal haemodynamic stability following intrathecal administration of hyperbaric levobupivacaine and hyperbaric bupivacaine in women undergoing caesarean section under spinal anaesthesia. The principal finding of this study was that hyperbaric levobupivacaine provided significantly superior maternal haemodynamic stability compared with hyperbaric bupivacaine. Patients receiving levobupivacaine demonstrated better preservation of systolic, diastolic, and mean arterial pressures, together with significantly lower incidences of hypotension and bradycardia and reduced requirements for vasopressors, glycopyrrolate, and intravenous fluid boluses. These findings indicate that hyperbaric levobupivacaine offers a favourable cardiovascular profile while maintaining satisfactory surgical anaesthesia. Baseline demographic, obstetric, and haemodynamic characteristics were comparable between the two study groups, indicating successful randomization and minimizing the influence of potential confounding variables. Consequently, the observed differences in intraoperative haemodynamic responses can reasonably be attributed to the pharmacological characteristics of the intrathecal local anaesthetics rather than baseline patient differences. Maternal hypotension remains the most common adverse effect of spinal anaesthesia during caesarean section. Sympathetic blockade following intrathecal local anaesthetic administration produces arterial and venous vasodilatation, reduced systemic vascular resistance, diminished venous return, and decreased cardiac output. Pregnancy-related physiological changes, including aortocaval compression by the gravid uterus and increased dependence on sympathetic tone, further increase susceptibility to hypotension. If prolonged or severe, maternal hypotension may result in nausea, vomiting, dizziness, decreased uteroplacental perfusion, and fetal compromise. These physiological considerations emphasize the importance of selecting an intrathecal local anaesthetic that provides adequate surgical anaesthesia while minimizing cardiovascular instability.⁴–⁹ In the present study, systolic blood pressure, diastolic blood pressure, and mean arterial pressure decreased following spinal anaesthesia in both groups, as expected. However, the reduction was significantly greater among patients receiving hyperbaric bupivacaine, particularly during the first 10 minutes after intrathecal injection, corresponding to the period of maximal sympathetic blockade. Hyperbaric levobupivacaine maintained significantly higher arterial pressures throughout this critical period, suggesting better preservation of cardiovascular homeostasis. One of the most clinically relevant findings of the present study was the significantly lower incidence of maternal hypotension in the levobupivacaine group (28%) compared with the bupivacaine group (61%). Furthermore, moderate and severe hypotension occurred considerably less frequently following levobupivacaine administration. These findings translated into a substantial reduction in vasopressor administration, glycopyrrolate use, and intravenous fluid bolus requirements, indicating not only statistical significance but also meaningful clinical benefit. Reduced vasopressor exposure may contribute to more stable maternal cardiovascular physiology and improved uteroplacental perfusion during caesarean delivery. Bradycardia occurred significantly less frequently in patients receiving hyperbaric levobupivacaine. Although serial heart rate measurements remained largely comparable between the groups, the lower incidence of clinically significant bradycardia further supports the improved haemodynamic profile of levobupivacaine. Collectively, these findings suggest that the principal advantage of levobupivacaine lies in superior maintenance of cardiovascular stability rather than differences in chronotropic response. The improved haemodynamic profile observed with levobupivacaine is pharmacologically plausible. Levobupivacaine is the pure S(-)-enantiomer of bupivacaine and exhibits lower affinity for myocardial sodium channels than racemic bupivacaine, resulting in reduced cardiotoxicity while preserving local anaesthetic efficacy. Experimental and clinical studies have demonstrated that levobupivacaine produces effective neuraxial blockade with less myocardial depression and a more favourable cardiovascular safety profile.¹⁰–¹² These pharmacological properties likely explain the reduced incidence of hypotension and lower vasopressor requirements observed in the present study. Our findings are consistent with those reported by Bremerich et al., who demonstrated improved maternal cardiovascular stability with intrathecal levobupivacaine while maintaining satisfactory surgical anaesthesia.¹⁴ Similarly, Goyal et al. observed fewer haemodynamic disturbances with levobupivacaine than with hyperbaric bupivacaine during elective caesarean section.¹⁵ More recent studies by Oraon et al. and Sinchana et al. have also reported favourable haemodynamic profiles with levobupivacaine, supporting its role as an effective alternative intrathecal local anaesthetic in obstetric practice.¹⁷–¹⁹ The present study extends these observations by evaluating a relatively large cohort of 200 parturients and by providing detailed serial assessment of haemodynamic variables throughout the intraoperative period. The prospective randomized design, adequate sample size, standardized spinal anaesthetic technique, identical intrathecal drug doses, and comprehensive serial haemodynamic monitoring strengthen the validity of the present findings. In addition to serial blood pressure measurements, clinically relevant outcomes including vasopressor requirement, glycopyrrolate administration, intravenous fluid bolus requirement, and severity of hypotension were evaluated, providing a comprehensive assessment of maternal cardiovascular stability. Nevertheless, certain limitations should be considered while interpreting the results. The study was conducted at a single tertiary care centre, which may limit the generalizability of the findings. The open-label design may have introduced observer bias, although the primary outcome measures consisted of objective haemodynamic variables. Furthermore, neonatal outcomes, umbilical cord blood gas analysis, maternal satisfaction, postoperative analgesic profile, and recovery characteristics were not evaluated. Future multicentre randomized controlled studies incorporating both maternal and neonatal outcomes would further clarify the role of hyperbaric levobupivacaine in obstetric spinal anaesthesia. Overall, the findings of the present study demonstrate that intrathecal hyperbaric levobupivacaine provides superior maternal haemodynamic stability compared with hyperbaric bupivacaine during caesarean section. The lower incidence of hypotension, reduced vasopressor requirement, and fewer haemodynamic interventions observed with levobupivacaine support its use as an effective alternative intrathecal local anaesthetic, particularly in obstetric patients where maintenance of maternal cardiovascular stability is a major clinical objective.

Intrathecal hyperbaric levobupivacaine (0.5%) demonstrated superior maternal haemodynamic stability compared with hyperbaric bupivacaine (0.5%) in women undergoing caesarean section under spinal anaesthesia. It was associated with better preservation of systolic, diastolic, and mean arterial pressures, a significantly lower incidence and severity of hypotension and bradycardia, and reduced requirements for vasopressors, glycopyrrolate, and intravenous fluid boluses. Hyperbaric levobupivacaine may therefore be considered a safe and effective alternative to hyperbaric bupivacaine for spinal anaesthesia in caesarean section, particularly in situations where maintenance of maternal haemodynamic stability is of paramount importance.

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