Intraocular pressure and ropivacaine in peribulbar block: a comparative study with bupivacaine.

BACKGROUND: The aim of this study was to compare the effects on intraocular pressure (IOP) of ropivacaine and bupivacaine in peribulbar block. METHODS: The study involved 40 patients with ASA physical status I, II or III undergoing cataract surgery under peribulbar block. Patients were allocated to two groups according to the local anesthetic used: Group R (n=20), 1.0% ropivacaine and Group B (n=20) 0.75% bupivacaine, both associated with 50 IU. ml-1 hyaluronidase, in peribulbar double injection technique. IOP was measured at four time points: 0=before block (control); 1=1 min after block; 2=5 min after block; 3=15 min after block. RESULTS: Mean values of IOP (mm Hg) after block were significantly lower in Group R in comparison to Group B: time point 1=13.4+/-3.2 vs 20.8+/-4.7; time point 2=10.9+/-3.7 vs 14.4+/-3.8; time point 3=7.7+/-4.0 vs 10.5+/-3.1. The variation of IOP was different in each group. In Group R, the mean values obtained at the three time points after block were significantly lower than the control; in Group B, the mean value of IOP rose significantly 1 min after block and was lower than control only at time point 3. CONCLUSIONS: Ropivacaine 1.0% associated with hyaluronidase in peribulbar block is better than 0.75% bupivacaine under the same standard conditions for lowering IOP in intraocular surgery. This effect is probably due to relaxation of the extraocular muscles after the block with both anesthetics, and possibly to a smaller intraocular blood volume due to vasoconstriction in the case of ropivacaine.

Ropivacaine in peribulbar block: a comparative study with bupivacaine.

BACKGROUND: Ropivacaine is a new local anesthetic with alleged lower systemic toxicity and slightly lower potency as compared with bupivacaine. The present study aimed to evaluate the efficacy of ropivacaine in peribulbar block, as compared with that of bupivacaine. METHODS: Eighty patients aged 45-92 years with physical status ASA I, II, or III were randomized to Group R (n=40) or Group B (n=40). Group R received 8.0 ml of 1.0% ropivacaine and Group B received 8.0 ml of 0.75% bupivacaine, both solutions with 50 IU/ml hyaluronidase, to induce peribulbar block according to the double-injection technique. Decreased ocular motility was the only criterion of successful block. RESULTS: The percentage of patients with decreased ocular motility showing successful block was higher in Group R 1 and 5 min after injection. A score indicating successful peribulbar block was found in all patients 10 min after injection. While no patient complained of a burning sensation during ropivacaine injection, 22.5% of the patients given bupivacaine reported this symptom. CONCLUSION: Both local anesthetics were effective in inducing peribulbar block for intraocular surgery. A tendency was noted to a faster onset of peribulbar block with ropivacaine; nevertheless, both drugs had a high degree of success for this block.

[Comparative study of circulatory response to tracheal intubation with atracurium and succinylcholine]. / Estudo comparativo das respostas circulatórias à intubação traqueal com atracúrio ou succinilcolina.

Changes in some circulatory parameters after orotracheal intubation (OTI) were investigated in 40 patients anesthetized with thiopental 5.0 mg.kg-1 and fentanyl 100 micrograms, receiving either atracurium 0.5 mg.kg-1 (n = 20) or succinylcholine 1.0 mg.kg-1 (n = 20) to facilitate intubation. In the succinylcholine group (SC), mean values of SAP, DAP, MAP, and HR rose significantly in relation to control at 30 sec and 2 min after OTI. In the atracurium group (A), mean values of SAP, DAP, and MAP rose significantly at 30 sec after OTI, however, contrary to the SC group, mean values of HR did not rise significantly after OTI. Mean values of the double product HR x SAP rose significantly at 30 sec, 2 min, and 5 min after OTI in the SC group, but only at 30 sec and 2 min after OTI in the A group. The magnitude of elevation of those circulatory parameters studied was always greater in the SC group than in the A group. The authors conclude that atracurium does not modify the nature of circulatory changes after OTI but is associated to such changes in a lesser degree when compared to succinylcholine in a standard induction technique with thiopental/fentanyl.