Ophthalmology
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Randomized Controlled Trial Comparative Study Clinical Trial
Prospective study of sub-Tenon's versus retrobulbar anesthesia for inpatient and day-surgery trabeculectomy.
Several retrospective studies have demonstrated the safety and efficacy of sub-Tenon's anesthesia in ocular surgery. This is the first prospective randomized study comparing sub-Tenon's versus retrobulbar anesthesia for glaucoma surgery. ⋯ Sub-Tenon's anesthesia is safe and effective for patients undergoing either inpatient or day-surgery trabeculectomies, and it requires less local anesthetic than retrobulbar anesthesia.
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Color Doppler velocimetry allows simultaneous imaging by B-scan and Doppler ultrasound. This facilitates estimation of blood velocity in the orbital vessels. A pulse arterial waveform providing blood velocity measurements can be obtained from the optic nerve head. The vascular pattern in this region consists of multiple peripapillary blood vessels and a central artery. The exact contribution of the arteries in this area to velocimetry readings was undetermined. ⋯ The results demonstrate that color Doppler ultrasound of the optic nerve head provides velocimetric measurements of blood flow in the central retinal artery. Although some investigators using different apparatuses have produced velocimetry measurements from the posterior ciliary arteries, in this study reliable measurements were not obtainable form color indices in the peripapillary area.
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Retinal arteriovenous malformations can be seen in a variety of ways and have multiple, associated, ocular changes that can affect vision. The authors report two cases of retinal arteriovenous malformation. In each case, a central retinal vein occlusion developed. ⋯ The authors propose that a turbulent flow, high intravascular volume, and arteriolar pressure in the venous side of the retinal arteriovenous malformation may lead to vessel wall damage, thrombosis, and occlusion. They also suggest that compression of the central retinal vein by the mass effect of the arteriovenous malformation on the optic nerve further leads to turbulence and thrombosis.
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Randomized Controlled Trial Comparative Study Clinical Trial
Peribulbar anesthesia. Effect of bicarbonate on mixtures of lidocaine, bupivacaine, and hyaluronidase with or without epinephrine.
The pH-adjustment of local anesthetic solutions with sodium bicarbonate may shorten onset time and improve spread of neural blockade. The authors undertook a prospective, double-masked, randomized study to see if a pH-adjusted mixture of lidocaine, bupivacaine, and hyaluronidase had faster and more complete onset of neural blockade, when used for peribulbar anesthesia. Eighty patients were randomly assigned to four groups and received a peribulbar block with one of four mixtures: group 1 (L) = 2% lidocaine, group 2 (LPH) = 2% lidocaine with 0.06 meq/ml sodium bicarbonate, group 3 (LE) = 2% lidocaine with 1:100,000 epinephrine (commercially prepared), or group 4 (LEPH) = 2% lidocaine with 1:100,000 epinephrine with 0.06 meq/ml sodium bicarbonate. ⋯ The LPH group had the fastest onset to complete akinesia (7.0 +/- 2.0 minutes, mean +/- SEM) when compared with the onset time of all other groups (group 1 = 11.5 +/- 1.9 minutes, group 4 = 13.1 +/- 1.4 minutes, and group 3 = 16.0 +/- 1.8 minutes, significance greater than 95% by analysis of variance). Furthermore, when compared with group 3 by analysis of variance, group 4 had a faster onset time. The authors conclude that pH-adjustment of solutions with bicarbonate of either lidocaine/bupivacaine/hyaluronidase or commercially prepared lidocaine with epinephrine/bupivacaine/hyaluronidase decreases the onset time of peribulbar anesthesia.