Evaluation of efficacy of peribulbar block with the combination of 2% lidocaine and 0.5% bupivacaine in comparison with 2% lidocaine and 0.75% ropivacaine in cataract surgery

INTRODUCTION: Cataract surgery is performed under peribulbar or retrobulbar block. Majority of the patients posted for cataract have some form of medical diseases like diabetes, hypertension, angina, ischaemic heart disease etc. Lidocaine and bupivacaine are the most commonly used local anesthetic for the block procedure. Here we compare the efficacy of peribulbar block in cataract surgery using the combination of 1:1 mixture of 2% lidocaine with 0.5% bupivacaine and 1:1 mixture of 2% lidocaine with 0.75% ropivacaine. MATERIALS AND METHODS: It is a prospective, randomized, double blinded study including 60 patients were devided into two groups of 30 each, Group-R received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0.75% ropivacaine and 15 IU/ml of hyaluronidase and group-B received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0. 5% bubivacaineand 15 IU/ml of hyaluronidase. Peribulbar block was performed as per Bloomberg’s modification of the Davis and Mandel technique where 5 ml of local anesthetic was injected in the infero temporal region and 3 ml of drug was injected in the superi nasal area. Patients were assessed for sensory block, eyelid and occular movements at an interval of 2 minutes. Systolic, diastolic and mean arterial pressures, heart rate, oxygen saturation, ECG were monitored non invasively at 1,3,5,8,10,15 and then every 10 minutes till the end of the surgery. OBSERVATION AND DISCUSSION: Mean time for the onset of sensory blockade was 2.70 ± 6.5 minutes in Group B and 2.63 ± 0.57 minutes in group R with P-value 0.671, showing no significant difference in the onset of sensory blockade. Onset of motor blockade was 6.53 ± 1.81 minutes in group B, and 7.57 ± 1.46 minutes in the group R, the P-value being 0.018 was statistically significant. Regarding the duration of analgesia, our study showed mean time for analgesia lasted for 295 ± 54.63 minutes in group B and 414.67 ± 99.47 in group R with P value 0.001 showing statistically significant prolongation of duration of analgesia with group R. We observed a significant increase of mean IOP in bupivacaine group from 13.333 ± 1.582 mm Hg to 21.966 ± 2.697 mm Hg, whereas in ropivacaine group it increased from 12.766 ± 1.222 mm Hg to 13.0 ± 1.341 mm Hg after peribulbar anaesthesia.