A comparison of the effects of alfentanil/droperidol or fentanyl/droperidol on intra-ocular pressure

Single injection peribulbar anaesthesia. Total upper eyelid drop as an end-point marker

A prospective, observer blinded study on 51 patients undergoing cataract surgery was conducted to assess Total Upper Eyelid Drop as a new end-point marker to single injection peribulbar block. At present, no such clinical marker exists to stop clinicians injecting more than necessary volumes of local anaesthetic and therefore to prevent dangerous increases in intra-ocular pressure. Using this technique, satisfactory ocular akinesia was achieved in 90% of eyes 10 min after injection. Operating conditions were satisfactory in 98% of cases. The mean (range) volume injected was 9.1 (4-15) ml. The mean increase in intra-ocular pressure immediately after injection was 6.9 mmHg, decreasing to 0.7 mmHg after 5 min without the application of ocular compression. We found a negative correlation between the increase in intra-ocular pressure and the volume of injection (p < 0.002), which has never previously been reported. We conclude that Total Upper Eyelid Drop is a reliable endpoint marker for producing satisfactory operating conditions for cataract surgery while minimising increases in intra-ocular pressure and its use may therefore avoid the risks associated with ocular compression.

Alfentanil/promazine versus meperidine/promazine as a sedative regimens during local analgesia for cataract operation

The influence of two intravenous (IV) sedative regimens on intra-ocular pressure (IOP) was investigated in conjunction with retrobulbar local analgesia. Forty patients of either sex, and similar age with body weight within 40-90 kg were allocated equally and randomly to two groups: Group A (alfentanil/promazine) and group M (meperidine/promazine). Measurement of IOP, systolic pressure, pulse rate, respiratory rate, PaCO2, PaO2 and O2 saturation were made before operation, after premedication, after IV sedation and post-operatively. In the Alfentanil group there was significantly stronger decrease of IOP (p < 0.001). In group A the IOP dropped from 18.1 +/- 3.2 mm Hg to 10.3 +/- 2.7 mm Hg, i.e. 43%, while in group M the reduction IOP was from 17.6 +/- 3.5 mm Hg to 12.6 +/- 1.9 mm Hg, i.e. 28.4%. Meperidine caused a significant increase in PaCO2 (4.2 +/- 0.3 mm Hg), however this increase was not sufficient to cause the IOP alterations. The oxygen saturation was lower in group M (decreased by 1.5 +/- 1% in group M versus decrease by 1.0 +/- 1.2% in group A). Cardiovascular parameters were more stable in group A. In conclusion the alfentanil regimen produced a better reduction of the IOP with excellent sedation, operative condition and least anaesthetic side effects.

Premedication for outpatient cataract surgery: a comparative study of intramuscular alfentanil, midazolam and placebo

The effects of i.m. alfentanil and midazolam on anxiety, sedation, hemodynamics, oxygen saturation and intraocular pressure were studied in 90 patients scheduled for outpatient cataract surgery with regional anesthesia. The study was randomized, double-blind, placebo-controlled, and performed on outpatients with ASA physical status I-III and mean age 67.7 +/- 11.7 years. Alfentanil (12.5 micrograms/kg) administered into the deltoid muscle had a marked anxiolytic and short sedative effect, and was associated with stable hemodynamics. Midazolam (20 micrograms/kg) administered similarly had a more prolonged anxiolytic and sedative effect, which impaired co-operation in some patients during surgery. The regional blockade was associated with a significant reduction of oxygen saturation (SpO2), regardless of the premedication used (P less than 0.05). A slight reduction of intraocular pressure (IOP) was found after premedication, but the change was not statistically significant. We conclude that i.m. alfentanil is well tolerated, and its anxiolytic and short sedative effects make it especially suitable as premedication for day-case cataract surgery.