Comparative study between ketamine and bupivacaine intrathecally in lower abdomen and lower limb surgery

Background: There is an on-going quest to know which agent is the better agent for intrathecal anaesthesia for pain relief due to surgical stimuli. Bupivacaine is commonly used local anaesthetic agent for spinal anaesthesia but it has some disadvantages like slower onset of action. Ketamine shows beside its general anaesthetic effect, a local anaesthetic like action. Series of studies have shown a potent analgesia after spinal administration of ketamine alone or in combination with opioids and α2 agonists, suggesting that ketamine alters pain perception at the spinal level. So, the objective of this study to compare the effectiveness of Ketamine action intrathecally with that of bupivacaine in respect to onset & duration of analgesia, onset & duration of motor block, sedation, cardiovascular effects and any other side effects like nausea, vomiting. Materials and methods: In this hospital based prospective comparative study, 100 patients of ASA (American Society of Anaesthesia) I and II scheduled for lower abdominal and lower limb surgery were taken. Patients were divided into two equal groups. Group I – Received 3 ml of hyperbaric bupivacaine (0.5%). Group II – Received 3 ml of hyperbaric Ketamine [taken from 2ml of preservative free ketamine (100mg) added with 2ml of 5% dextrose]. Onset and duration of analgesia, onset and duration of motor block, central effects like sedation, effects on cardiovascular system and any other side effects were compared in both the groups. Analysis data was carried out using the available statistical package of SPSS-20 (Statistical Package for Social Science – version 20 “PASW” statistics). Results: The onset of sensory block and motor block were faster in ketamine group as compared to bupivacaine group. The duration of analgesia was longer in ketamine group as compared to bupivacaine group. The duration of motor block was almost equal in both the groups. About sedation, more patients were sedated in ketamine group as compared to bupivacaine group. Patients in ketamine group were more stable cardiovascularly as compared to bupivacaine group. Conclusion: Ketamine can be used as a pure local anaesthetic for spinal anaesthesia with advantage of faster onset of analgesia and motor block as well as longer duration of analgesia. Ketamine group appeared more hemodynamically stable also. So, ketamine can be used as an alternative to bupivacaine for moderate duration of lower abdomen and lower limb surgery despite its central effect like sedation.