Background: Spinal anaesthesia with ropivacaine is widely used for lower abdominal and lower limb surgeriesdue to its favorable sensory-motor separation and safety profile. The baricity of the local anaesthetic solutioninfluences onset time, density of block, and hemodynamic effects. Plain (isobaric) solutions tend to spread unpre-dictably, whereas hyperbaric formulations—made denser by addition of dextrose—may offer more reliable blockcharacteristics. This study compares onset, level, duration of sensory and motor blockade, haemodynamicchanges, and adverse effects between plain and hyperbaric 0.75% ropivacaine in elective lower abdominal andlower limb procedures.Methods: In this prospective, randomized, double-blinded trial, 100 ASA I–II adult patients (age 18–65 years)scheduled for elective lower abdominal or lower limb surgery under spinal anaesthesia were enrolled. Patientswere randomized to receive 3 mL of 0.75% isobaric ropivacaine (Group P, n=50) or 3 mL of 0.75% hyperbaricropivacaine (Group H, n=50). Spinal puncture was performed at L3–L4 with a 25G Whitacre needle in the sittingposition. Sensory block onset (time to T10 dermatome), maximum level achieved, and two-segment regressiontime were recorded. Motor block was assessed by Modified Bromage Scale every minute until full block. Hemo-dynamic parameters (heart rate, blood pressure) were monitored every 2 minutes for 20 minutes, then every 15minutes until end of surgery. Adverse events (hypotension, bradycardia, nausea, headache) were documented.Results: Group H exhibited a faster sensory onset (mean ± SD: 3.2 ± 0.8 min vs. 4.5 ± 1.1 min; p < 0.001) andhigher maximum block level (T4 vs. T6; p = 0.002). Two-segment regression was prolonged in Group H (180 ±22 min vs. 150 ± 18 min; p < 0.001). Motor block onset and duration were also significantly faster and longerrespectively in Group H (onset 4.0 ± 0.9 min vs. 5.3 ± 1.2 min, p < 0.001; duration 160 ± 20 min vs. 135 ± 15min, p < 0.001). Incidence of hypotension was higher in Group H (30% vs. 16%; p = 0.04), though easily managedwith fluid bolus and vasopressors. No significant differences in bradycardia or other side effects were noted.Conclusions: Hyperbaric 0.75% ropivacaine provides faster onset, higher block level, and longer duration ofsensory and motor blockade compared with plain solution but is associated with a greater incidence ofhypotension. Selection of hyperbaric formulation may be advantageous when rapid, dense block is desired, withpreparedness to manage hemodynamic changes.
Kant et al. (Thu,) studied this question.