A COMPARISON OF THE EFFECTS OF 2% LIGNOCAINE AND 0.5% BUPIVACAINE WITH 0.75% ROPIVACAINE AS PERIBULBAR BLOCK FOR CATARACT SURGERIES IN ASA 2 PATIENTS

Abstract

Background: The most commonly accepted and used route of anaesthesia administration for cataract surgeries is the peribulbar route with a mixture of 2% lignocaine and 0.5% bupivacaine. It is a simple technique which produces the desired anaesthetic, analgesic and akinetic effect on the eye. But both these anaesthetic agents are reported to produce cardiovascular and central nervous system side-effects. Safer agents like ropivacaine are being introduced into the clinical practice. Most of the patients undergoing cataract surgeries have associated comorbidities such as a hypertension, diabetes mellitus and asthma. Also, today's population is largely addicted to alcohol and smoking. Such patients are graded based on the American Society of Anaesthesiologists (ASA) grades prior to surgeries to assess their perioperative risks. This study focuses on comparing the characteristics of peribulbar blocks with 0.75% ropivacaine with the popularly used bupivacaine and lignocaine mixture and to assess their cardiotoxicity in ASA 2 patients. Methods: Eighty patients of ASA 2 category with comparable demographic characteristics were allocated to two random groups of 40 each. Patients of groups A (lignocaine and bupivacaine) and B (ropivacaine) were given 8 ml mixture of 2% lignocaine (4 ml) + 0.5% bupivacaine (4ml) and 8 ml of 0.75% ropivacaine each and 100 IU of hyaluronidase respectively. Block characteristics like onset and duration of action and hemodynamic variables like systolic blood pressure, diastolic blood pressure and pulse rate were recorded, studied and analysed. Results: Duration of onset of the block in both the groups was comparable but the total duration of the block and analgesia was found to be longer in group A than in group B. It was observed that there were uctuations in the recorded values of blood pressure and pulse rate intraoperatively and postoperatively in Group A whereas these parameters were stable in Group B. Conclusion: Ropivacaine 0.75% in a volume of 8 ml with 100 IU of hyaluronidase is as effective as a 4:4 mixture of bupivacaine 0.5% and lignocaine 2% in a volume of 8 ml with 100 IU of hyaluronidase with regards to onset of action. The total duration of the block and hemodynamic changes are less uctuating with the usage of ropivacaine indicating that ropivacaine is a safer drug for induction of peribulbar anaesthesia in ASA 2 grade cataract patients.