Comparative Effects of Intrathecal Midazolam and Bupivacaine Combination with Bupivacaine Alone for Spinal Anaesthesia in Gynaecological Procedures

Abstract

The present study was undertaken to determine the onset of sensory block, time to achieve maximum level of sensory block and analgesic efficacy of intrathecal midazolam given in combination with bupivacaine and also to observe undesirable side effects(if any) produced by midazolam bupivacaine combination. One hundred patients (ASA I & ASA II) scheduled for elective gynaecological surgery in age range of 45-60yrs were randomly allocated to two equal groups. Group I received 12.5mg of 0.5% hyperbaric bupivacaine with 0.4ml of normal saline in L3- L4 interspace while Group II received 12.5mg(2.5ml) of 0.5% hyperbaric bupivacaine with 0.4ml (2mg) of preservative free midazolam. Standard monitoring of haemodynamic parameters was recorded throughout the procedure. Onset of sensory block, time to achieve maximum sensory block and the level of block were also recorded. Sedation scores were recorded every two minutes for twenty minutes and then every 10 minutes till the end of surgery. Pain assessment was done by VAS score. Duration of pain free period up to rescue analgesia or VAS score greater than 40mm was noted. Unwanted side effects were also noted. There was no significant difference in demographic distribution of patients. There was no statistically significant difference in onset of sensory block (p=0.735) and time to achieve maximum level of sensory block in both groups (p=0.45). Sedation score was comparable in both groups. There was a significantly higher duration of pain free period in Group II (274.9±18.07min) than Group I (187.2±16.8 min) (p<0.05). The number of patients developing bradycardia and hypotension was comparable. Midazolam prolonged the post-operative analgesia of intrathecal bupivacaine in gynaecological patients without increasing the incidence of side-effects.