Comparison of the effect of different glucose concentration on the intrathecal spread of 0.5% bupivacaine and 2% lidocaine

Abstract

O-30 Introduction: Among the factors that govern the spread of local anaesthetic (LA) solutions through the CSF, glucose concentration of the solution has the most evident influence. The aim of this study was to investigate whether LA solution with low concentration of glucose has potential advantages on the development of the block after spinal anaesthesia with decreased risk of extensive cephalic spread of the LA. Methods: Eighty patients who underwent spinal anaesthesia were randomly allocated into four groups to receive different LA solution: Group 1:0.5% bupivacaine in 8% glucose; Group 2: 2% lidocaine in 6% glucose; Group 3: 0.5% bupivacaine with 0.8% glucose; and Group 4: 2% lidocaine with 0.6% glucose. LA solutions were injected at L3-L4. Standard technique was used:patient in sitting position; 4 ml LA solution was injected over 15 s through a 26 G Quincke needle. Results: Onset of block was rapid in all groups, but the mean time to block the T10 dermatome was shorter in patients from Groups 1 and 2 compared with patients from Group 3 and 4 (P>0.05). Mean block in patients who received LA solution with higher glucose concentration was more extensive (maximum level was higher by two dermatomes) than in the patients who received LA solution with low glucose concentration. The range of block in Group 1 and 2 was higher than in Group 3 and Group 4. (Table)Table 1: Characteristics of the block after spinal anaesthesia with different glucose concentration of LA solution Conclusion: Solutions of LA with low glucose concentration (just sufficient to make the solution only slightly hyperbaric in comparison with CSF), have advantages on the intrathecal LA spread when injected in the L3-L4 interspace by a standard technique. Block to the level of the umbilicus is reached without affecting the upper thoracic dermatomes.