Fortschritte der Ophthalmologie : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
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In a study of 280 patients (265 with cataract, 15 with strabismus), we investigated the ocular circulatory effects of 3 methods of anesthesia widely used in ophthalmic surgery, retrobulbar, peribulbar and general anesthesia. Retrobulbar anesthesia (RETRO) was performed with 2, 5 or 8 ml of a mixture (BLH-Mix) of bupivacaine 0.75%, lidocaine 2% and hyaluronidase; with 5 ml BLH-Mix and addition of adrenaline in a low (1:500,000) or a higher (1:200,000) concentration; with 5 ml bupivacaine 0.75% or lidocaine 2% or mepivacaine 2%; with 5 ml mepivacaine 2% and addition of 150 units hyaluronidase; or with 5 ml BLH-Mix plus adrenaline and additional oculopression. Peribulbar anesthesia (PERI) was performed with 8 ml BLH-Mix (5 ml inferotemporally/3 ml superonasally) or 10 ml BLH-Mix (8/4) injected outside the muscle cone. General anesthesia was performed using halothane (inspiratory concentration 0.5 vol%) and nitrous oxide (65 vol%); respiration was adjusted to produce slight hyperventilation (alveolar pCO2 33 mmHg) or forced hyperventilation (pCO2 20-25 mmHg), respectively. The following variables were measured; systolic ciliary perfusion and blood pressures (PPs,cil and Ps,cil, respectively) and ocular pulsation volume (PVoc) using oculo-oscillodynamography of Ulrich, and the intraocular pressure (IOD) using the Draeger handapplanation tonometer. ⋯ The anesthesia-induced lowering of both ocular perfusion and blood pressures as well as of the ocular pulsation volume, which is a measure of the pulsatile choroidal blood flow, can be interpreted as reflecting an inhibitory influence on ocular circulation. We suggest the following mechanisms to account for the changes during LA: elevation of IOP, adrenaline-induced retrobulbar vasoconstriction, LA-induced retrobulbar vasoconstriction (hypothetical), improved penetration of LA brought about by the orbital compression occurring during oculopression. The relative significance of the separate mechanisms differs, however, between the various LA types. The changes found during general anesthesia are attributable to the halothane-induced reduction of systemic blood pressure and cardiac stroke volume as well as to a relative hyperventilation-induced choroidal vasoconstriction. The results are relevant for ophthalmic surgery with respect to the prevention of complications and problems depending on pathologic or at least unphysiological changes in ocular circulation, e.g...
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Uni- or bilateral dilatation of pupils that are not reactive to light and lack miosis in response to 1% pilocarpine may be caused by contact with plants containing alkaloids such as scopolamine and atropine. Other causes of a non-light-reactive dilated pupil, such as Adie's tonic pupil, third nerve palsy and lesion of the mesencephalic pretectal region, must be excluded before testing the iris sphincter reaction to 1% pilocarpine. Among the naturally growing flowers in Germany, deadly nightshade (Atropa belladonna), jimson weed (thornapple, Datura stramonium) and black henbane (Hyoscyamus niger) contain enough alkaloids to cause mydriasis by direct contact. ⋯ These plants can grow very large and are often planted in tubs. They have to be cut back each year before the winter. This is typically how the eye is contaminated by parts of the plants, which can cause dilatation of the pupil mimicing a neuroophthalmological disorder.
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Fortschr Ophthalmol · Jan 1990
Randomized Controlled Trial Comparative Study Clinical Trial[Modification of hemodynamic retrobulbar anesthesia effects by different oculopression procedures (with and without orbital compression)].
For studying the influence of orbital compression--an essential component of the clinically used methods of oculopression--on the hemodynamic effects of retrobulbar anesthesia, two series of investigations were performed preoperatively in 40 patients. In series 1, we initially performed retrobulbar anesthesia (RBA) with 5 ml of a bupivacaine/lidocaine mixture with adrenaline. RBA was followed by a 15-min period of suction-cup oculopression (SCO; negative pressure -100 and -150 mmHg in 10 patients each), which represents an experimental "pure" oculopression without compression of orbital tissue. ⋯ After SCO, pio was lowered by an average of 8.5 mmHg, and the ocular blood pressures remained unchanged at the post-injection levels. The perfusion pressures, however, were increased to their initial values, and even beyond in some cases. Thus, the inhibitory effects of RBA on ocular circulation are partially set off by the effects of SCO.(ABSTRACT TRUNCATED AT 250 WORDS)
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Fortschr Ophthalmol · Jan 1990
Randomized Controlled Trial Clinical Trial[Suction cup ocular pressure versus Vörösmarthy oculopression. Biometry differences].
In a 20-min follow-up after oculopression, biometric measurements were taken before, immediately after, and 5, 10, 15 and 20 min after finishing oculopression. Thirty-two eyes were measured by ultrasound using the immersion technique with a 10 MHz A-scan probe. Sixteen cataract patients more than 50 years of age and 16 healthy young subjects up to 30 years of age took part in the study. ⋯ Suction-cup oculopression revealed no distinct changes in these compartments. Nevertheless, 10 min after oculopression, there was no statistically significant difference between the two oculopression techniques. When comparing the age groups, the cataract patients showed more express change than the younger subjects.
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Fortschr Ophthalmol · Jan 1990
Randomized Controlled Trial Comparative Study Clinical Trial[Eyelid akinesia after various techniques of facial nerve block].
Lid akinesia was investigated after the application of one of three techniques to achieve facial nerve blockade in each of 32 patients undergoing cataract surgery. Modifications of the O'Brien, Atkinson and Lint block techniques were applied in twelve, ten, and ten patients, respectively. Before and 1, 3, 5 and 10 min after administration of 5 ml 1% lidocaine (Xylocain) with naphazolin nitrate 1:20,000 (Privin) voluntary muscle activity of the orbicularis oculi muscle was recorded, and the area under the EMG curve was calculated for quantitative comparison of muscular activity between the groups. ⋯ In six additional patients, the topographic distribution of a mixture of metrizamide (Solutrast) and the anesthetic solution was evaluated radiographically to assess potential causes of differences in the effectiveness of the block techniques. Within 1 min after modified O'Brien block, the voluntary activity of the orbicularis oculi muscle and the force of lid closure were significantly, lower than those after both the modified van Lint and the Atkinson techniques: furthermore, a significant decrease in the voluntary lid movement was observed within 3 min. Whereas the modified O'Brien block nearly abolished voluntary muscle activity, force of lid closure and lid movement, there was only a minor decrease in the area under the EMG curve and in the force of lid closure after the modified van Lint and Atkinson blocks (about 20%).(ABSTRACT TRUNCATED AT 250 WORDS)