The present study was conducted in 120 patients receiving peribulbar block for cataract extraction to test efficacy of peribulbar blockade using a temperature — adjusted lidocainebupivacaine mixture (warmed to 3SFC) and to compare it to alkalinized mixtures with or without hyaluronidase ; both at room temperature.
Patients were randomly assigned to one of 3 groups A, B and C (n = 40), who receieved 8 ml of 3 different local anaesthetic mixtures. Group A received the solution LBpff6.7; that is 1:2 mixture oflidocaine 2% & bupivacaine 0.5% alkalinized to apH of 6.7. Group B received the solution LBHPH6.7; that is the same mixture to which 150 IU of hyaluronidase was added Group C received the solution of LBtempi8 / that is plain 1: 2 mixture of lidocaine-bupivacaine warmed to a temperature of 38C. The No. of successful blocks after 10 min was significantly lower in group A (13 out of40) compared to groups BandC (31 and 33 respectively). Onset time to occular akinesia was significantly longer in group A (9.5 4.2 min.) than in groups B and C (6.7 3.9 and6.4+4.0 min respectively).
Patients of group B felt pain significantly earlier in the postoperative period (after 157.5 42.1 min) than patients of groups A and C (after 251.2 36.7 and 246.3 45.2 min respectively). All patients with successful blocks had adequate analgesia and lid akinesia enough for surgery. The present study demonstrated that warming of 1:2 mixture oflidocaine 2% and bupivacaine 0.5% to 38C before peribulbar blockade is a simple, safe and effective method for increasing the success rate and improving the quality of block. This method could replace hyaluronidase avoiding risks associated with its use |
