# A Comparative Study of Premixed Versus Succedent Administration of Dexmedetomidine and Bupivacaine in the Subarachnoid Block for Infraumbilical Surgeries

## TL;DR

This study compares two methods of administering drugs for spinal anesthesia to see which provides better pain relief and fewer side effects after lower abdominal surgeries.

## Contribution

The study introduces a comparison of sequential versus premixed administration of dexmedetomidine and bupivacaine in spinal anesthesia for infraumbilical surgeries.

## Key findings

- Sequential administration (Group A and C) resulted in longer sensory and motor block durations.
- Premixed administration (Group B) had higher rates of bradycardia and hypotension.
- Group C had the shortest motor block onset time.

## Abstract

Background: The suggested method for infraumbilical surgeries is spinal anaesthesia. Postoperative pain management is challenging, as spinal anaesthesia utilising solely local anaesthetics provides only a short analgesic effect. Therefore, early pain relief is necessary in the postoperative period.

Aims and objectives: In this study, dexmedetomidine and bupivacaine were administered either premixed in a single syringe or sequentially in separate syringes for subarachnoid block in infraumbilical surgeries across different study groups. We compared the sensory and motor block characteristics, intra-operative hemodynamics, postoperative pain relief, and any side-effects in patients undergoing lower abdominal surgeries. The effect of administering dexmedetomidine before bupivacaine heavy and vice versa on these parameters was also assessed.

Methodology: The study involved 120 patients, as classified by the "American Society of Anaesthesiologists", physical status I and II, all scheduled for lower abdominal procedures (gynaecological, urological, orthopaedic, and other lower abdominal procedures) under spinal anaesthesia. Three groups of patients were randomly selected: Group A received two intrathecal injections. The first injection consisted of 5 mcg of dexmedetomidine diluted in preservative-free normal saline (0.5 mL), followed by 12.5 mg of 0.5% heavy bupivacaine (2.5 mL), both in separate 3 mL syringes. In Group B, participants received intrathecal injections of premixed solution divided into two separate 3 mL syringes, one with 2.5 mL and the other with 0.5 mL of premixed solution. A premixed solution (3 mL) was made with 5 mcg of dexmedetomidine diluted in 0.5 mL of preservative-free normal saline and 12.5 mg of 0.5% heavy bupivacaine (2.5 mL). Group C participants were given two consecutive intrathecal injections, first 12.5 mg of 0.5% heavy bupivacaine (2.5 mL) using a 3 mL syringe and 5 mcg of dexmedetomidine diluted in preservative-free normal saline (0.5 mL) in a second 3 mL syringe. Statistical analysis has been performed utilizing Statistical Product and Service Solutions (SPSS, version 20; IBM SPSS Statistics for Windows, Armonk, NY).

Results: The earliest average onset time for sensory block has been observed in Group A, which was monitored by Groups B and C. Group C had the lowest average onset time for motor block, followed by Groups A and B. Groups A and C experienced sensory and motor blockage for more extended periods. Compared to Groups A and C, Group B patients have a greater incidence of bradycardia as well as hypotension.

Conclusions: The research illustrates that, in contrast to spinal anaesthesia with a premixed dosage of hyperbaric bupivacaine and dexmedetomidine, sequential intrathecal injection produces a longer sensory and motor block with a quicker onset.