Fixed Dose versus Height-Adjusted Conventional Dose of Intrathecal Hyperbaric Bupivacaine for Caesarean Delivery: A Prospective, Double-Blinded Randomised Trial.

Katarzyna Białowolska,Małgorzata Malec-Milewska,Agnieszka Sękowska,Bartosz Horosz

doi:10.3390/jcm9113600

Abstract

The optimal intrathecal dose of local anaesthetic for caesarean section (CS) anaesthesia is still being debated. We performed a study to compare the effectiveness and safety of spinal anaesthesia with 12.5 mg of hyperbaric bupivacaine and a dosing regimen of conventional doses adjusted to parturient height. One hundred and forty parturients scheduled for elective CS were enrolled. The fixed-dose group (FD) received a spinal block with 12.5 mg of hyperbaric bupivacaine with fentanyl, whereas the adjusted-dose group (AD) received a height-adjusted dose of bupivacaine (9–13 mg) with fentanyl. Sensory block ≥ T5 dermatome within 10 min and no need for supplementary analgesia were set as the composite primary outcome (success). Rates of successful blocks and complications were compared. Complete data were available for 134 cases. Spinal anaesthesia was successful in 58 out of 67 patients in the FD group and 57 out of 67 in the AD group (p > 0.05). Eight spinals in each group failed to produce a block ≥ T5 in 10 min, and one patient in the FD group and two in the AD group required i.v. analgesics despite sensory block ≥ T5. No differences were noted in terms of hypotension, bradycardia and nausea between the FD and AD groups. Compared to the height-adjusted dose regimen based on conventional doses of hyperbaric bupivacaine, the fixed dose regimen of 12.5 mg was equally effective and did not increase the risk of spinal block-related complications.

Highlights

Spinal block is the most common type of anaesthesia used for caesarean section (CS), with nearly 95% of elective and 45% of emergency procedures performed under spinal or spinal-epidural anaesthesia [1,2]
Limiting the intrathecal dose of local anaesthetic (LA) to doses as low as 6–7 mg of hyperbaric bupivacaine has been proposed in order to minimize the complication rate, but this comes at an increased risk of inadequate anaesthesia and may require the use of combined spinal-epidural technique to assure the desired level of effectiveness [7,8,9]
Three patients in each group were excluded from analysis: in four cases, there was no clinical sign of spinal blockade after intrathecal injection and the procedure had to be repeated

Summary

Introduction

Spinal block is the most common type of anaesthesia used for caesarean section (CS), with nearly 95% of elective and 45% of emergency procedures performed under spinal or spinal-epidural anaesthesia [1,2]. The intrathecal dose of hyperbaric bupivacaine effective in 95% (ED95) of spinals for caesarean section has been established to be 11.2 mg [4], 0.06 mg/cm of height [5], or even more recently 12.6 mg of hyperbaric bupivacaine [6]. Limiting the intrathecal dose of local anaesthetic (LA) to doses as low as 6–7 mg of hyperbaric bupivacaine has been proposed in order to minimize the complication rate, but this comes at an increased risk of inadequate anaesthesia and may require the use of combined spinal-epidural technique to assure the desired level of effectiveness [7,8,9]. Dose-adjustment protocols were proposed for conventional doses, with the main interest in limiting the rate of spinal block-related maternal hypotension. Despite convincing data on no relation between intrathecal spread of local anaesthetic and maternal height and weight, adjusting the dose of LA to patient size is still being debated [10,11,12,13,14,15]

Methods

Results

Discussion

Conclusion