A Comparative Study of Safety and Efficacy between 0.75% Ropivacaine and 1:1 Mixture of 2% Lidocaine with 0.5% Bupivacaine in Peribulbar Blocks for Cataract Surgery

Anesthesia for ophthalmic surgery requires a careful approach. Majority of the patients presenting belong to the geriatric age group. Surgery in this population group is always challenging and is associated with various risks, whether it is performed under general anesthesia or regional anesthesia.

As general anesthesia can be hazardous in the elderly population and not advisable in view of a short procedure (15–20 min), needle blocks especially peribulbar blocks are the most preferred for anesthesia in cataract surgeries.

Peribulbar anesthesia is routinely performed with a mixture of local anesthetics, most commonly bupivacaine and lidocaine.Although Bupivacaine is commonly used due to its longer duration of action, it became apparent that accidental overdose was often fatal due to severe cardiac arrhythmias and neurotoxic effects.1

The aminoamide, Ropivacaine, a derivative of mepivacaine, was introduced in 1996 as the safer alternative to bupivacaine.It has a significantly higher threshold for cardiac and CNS toxicity than bupivacaine due to its less lipophilic and stereoselective properties.2

Hence we intend to take up this study in out set up to compare the safety and efficacy between 0.75% Ropivacaine and 1:1 mixture of 2% Lidocaine and 0.5% Bupivacaine in peribulbar blocks in patients undergoing cataract surgery.

Another comparative study on 80 patients showed that Ropivacaine 0.5% and lidocaine 2% as a 1:1 mixture in a volume of 8 ml with 100 IU of hyaluronidase was as effective as a 1:1 mixture of bupivacaine 0.5% and lidocaine 2% in a volume of 8 ml with 100 IU of hyaluronidase with regards to onset and total duration of the block and side effects and hemodynamic changes.1

A case control study compared 2 local anaesthetics (lignocaine + Bupivacaine with Ropivacaine) in patients undergoing cataract surgery and concluded that Ropivacine as a local anaesthetic drug has slightly higher efficacy and faster onset than that of traditional lignocaine with bupivacaine combination.3

Ropivacaine is found to be a suitable choice for local anesthesia showing a short and predictable onset of surgical anesthesia with better control of post-operative pain relief. 4

A study comparing Ropivacaine & mixture of bupivacaine/lignocaine revealed that ropivacaine represents an effective alternative to mixture of bupivacaine/lignocaine in peribulbar anaesthesia, due to the similar characteristics in motor and sensitive blockade, intraocular dynamics and its lower systemic toxicity. Therefore, 0.75% ropivacaine alone is a suitable option for performing peribulbar block in cataract surgery.5

In ophthalmic surgeries, ropivacaine in peribulbar anesthesia is associated with lower rate of block failure when compared to bupivacaine.6