A Study of Intrathecal Bupivacaine and Bupivacaine With Midazolam in Lower Abdominal Surgeries

Abstract

BACKGROUND Several adjuvants have been tried along with local anaesthetic in spinal anaesthesia for prolonging the duration of analgesia . Intrathecal midazolam produces anti-nociception and potentiates the effect of local anaesthetics. The aim of this study is to study the comparison between intrathecal bupivacaine and bupivacaine with midazolam with spinal anaesthesia. MATERIALS AND METHODSThis is a comparative, randomised, double-blinded study of 90 patients within the age group of 18 -60 years with ASA status I or II, undergoing various lower abdominal surgical procedures. They were randomly allocated to one of the two groups, each containing 45 patients as follows: The B group receiving 2 mL of 0.5% hyperbaric bupivacaine (10 mg) and 1 mL of 0.9% saline intrathecally; the BM group receiving 2 mL of 0.5% hyperbaric bupivacaine (10 mg) with 1 mL (1 mg) of preservative-free midazolam. The onset, duration of sensory/ motor block, the time to achieve maximum sensory block and the level of block, time for first rescue analgesia, sedation score, quality of anaesthesia and side effects were noted. RESULTSThere was no significant difference in the demographic distribution of the patients. There was no statistically significant difference in the onset of the sensory block (p-value > 0.05) and time to achieve maximum level of sensory block in both groups (p-value > 0.05). Mean duration of sensory block or effective analgesia in group BM was 330.88 ± 16.36 minutes, while that in group B was 273.68 ± 15.69 minutes, which was statistically significant (p-value < 0.05). There was no statistically significant difference between both the groups with respect to motor block and quality of anaesthesia. The sedation score was comparable in both groups. The side effect profiles in both groups were also comparable. CONCLUSIONThe addition of 1 mg preservative-free midazolam to 0.5% hyperbaric bupivacaine prolongs the duration of effective analgesia as compared to bupivacaine alone and delays the need for postoperative rescue analgesics without affecting the onset of block and without increasing the risk of side effects. Spinal anaesthesia with bupivacaine is routinely administered for lower abdominal surgeries with adequate motor blockage, additionally providing effective pain relief in the initial post-operative period due to its long duration of action. 1 However, the Cardiovascular Collapse/ Central Nervous System (CC/CNS) ratio of bupivacaine is narrow (2.7) with a higher propensity of irreversible cardiovascular collapse. 1 'Financial or Other Competing Interest': None. Submission 22-11-2017, Peer Review 16-12-2017, Acceptance 22-12-2017, Published 08-01-2018. Corresponding Author: Dr. Partha Pratim Deka, Meridiyen Apartments, Apt. No. 409, Deralakatte, Yenepoya Medical College, Mangalore-575018, Karnataka, India. E-mail: dr.parthadeka@live.in DOI: 10.14260/jemds/2018 Therefore, in order to minimise the dose of bupivacaine and to reduce its side effects the use of an adjuvant that would prolong its duration...