A comparative study of epidural 0.5% isobaric levobupivacaine and epidural 0.5% isobaric levobupivacaine with dexmedetomidine for patients undergoing elective infraumbilical and lower limb surgeries

Abstract

BACKGROUND: The quest for searching newer and safer anaesthetic agents has always been one of the primary needs in anaesthesiology practice. Regional anaesthesia techniques have seen numerous modifications over the last two decades with the advent of many newer and safer local anaesthetics Keeping these factors in mind, S (−)-enantiomer of bupivacaine, levobupivacaine has been developed. The advantages of levobupivacaine over bupivacaine are decreased cardiovascular toxicity and there is also a relatively decreased motor nerve fiber penetration and block, thereby a decreased post operative motor blockade and thus early ambulation of the patients can be achieved. The present study compared the effects of addition of epidural dexmedetomidine 50 micrograms to epidural 0.5% levobupivacaine for infraumbilical and lower limb surgeries. METHODS: Sixty patients of either sex belonging to ASA I & II in the age group of 25-45 years scheduled for infraumbilical and lower limb surgeries were randomly divided into 2 groups (30 each) to receive 0.5% isobaric levobupivacaine 20 ml epidurally with 0.5 ml distilled water (Group A) and 0.5% isobaric levobupivacaine 20 ml plus 0.5 ml dexmedetomidine containing 50 micrograms (Group B). This study evaluated the following parameters like time of onset of sensory blockade at T10 level, maximum sensory blockade achieved and time taken to achieve the same, onset time of motor blockade, degree of motor blockade, time taken to achieve maximal motor blockade, hemodynamic changes in pulse rate, blood pressure and oxygen saturation, side effects and complications, intraoperative sedation scores, duration of analgesia, sensory & motor blockade, and any postoperative adverse reactions. RESULTS: The data obtained from the above parameters were statistically analysed using SSPS version 16 software. Student t test was used for parametric data and Chi-square test for non parametric data. P<0.05 was considered as statistically significant. Maximal sensory level was achieved with addition of dexmedetomidine ranging from T4 to T6.Also the onset time of motor blockade was shortened with group A showing 19.33 minutes and group B showing only 14.5 minutes.The maximal motor blockade achieved was also intense (Bromage 3) with the addition of dexmedetomidine. Duration of analgesia, sensory and motor blockade were prolonged when levobupivacaine is combined with dexmedetomidine epidurally. Changes in hemodynamic parameters (blood pressure & heart rate) were very minimal in the dexmedetomidine group. Adverse effects experienced in general were statistically insignificant in both the groups. Mean sedation score in group B (Dexmedetomidine group) was predominantly found to be 2 as per Ramsay sedation score. None of the patients in group B had deep sedation or profound respiratory depression.