Spinal anaesthesia with low-dose bupivacaine in marginally hyperbaric solutions for caesarean section: A randomised controlled trial.

BACKGROUND

Conventional hyperbaric spinal anaesthesia solution (SAS) with 8% glucose and low-dose bupivacaine may reduce the incidence of hypotension in caesarean section compared to standard doses, and marginally hyperbaric SAS (≤0.8% glucose) can induce a lower block level and a lower incidence of hypotension in nonobstetric patients than conventional 8% glucose SAS.

OBJECTIVE

The objective of this study was to evaluate the clinical efficacy of marginally hyperbaric low-dose bupivacaine solutions used for spinal anaesthesia during caesarean section.

DESIGN

A randomised, controlled clinical trial.

SETTING

Single medical centre.

PATIENTS

One hundred twenty women scheduled for elective caesarean section were randomised into four groups.

INTERVENTIONS

Caesarean section after combined spinal-epidural anaesthesia using hyperbaric preparations of low-dose SAS (7.2 mg bupivacaine and 2 μg 1.6 ml sufentanil in one of the following: 8%, 0.8%, 0.5% or 0.33% glucose solution.

MAIN OUTCOME MEASURES

The dermatomal sensory block and degree of motor block of the lower extremities and adverse effects of anaesthesia were recorded.

RESULTS

The maximum cephalad sensory block level and the incidence of hypotension decreased as the density of SAS fell (T1, T2, T4 and T6, P < 0.001; 48.3, 30, 13.3 and 10.3%, P = 0.003). The incidence of shivering reduced with decreasing density of SAS (P < 0.05). There was no significant difference in the quality of anaesthesia (efficacy of motor block and sensory block) between the groups (P > 0.05).

CONCLUSION

Compared with conventional 8% glucose hyperbaric SAS, marginally hyperbaric (0.5 or 0.33% glucose) low-dose bupivacaine solutions led to a significantly lower height of cephalad spread and incidence of hypotension with no impact on the efficacy of spinal anaesthesia for caesarean section.