[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. In series 2, RBA was followed by a 15-min period of Vörösmarthy oculopression (VMO; pressure 30 and 40 mmHg in 10 patients each) which produces both ocular and orbital compression. Before and again after both RBA and oculopression, we determined the intraocular pressure (pio), the systolic retinal and ciliary perfusion pressures or blood pressures, respectively, and the ocular pulsation volume (PVoc) using oculo-oscillo-dynamography. After injection, pio was increased by an average of 4.5 mmHg, the ocular perfusion and blood pressures were lowered by 8.5 and 4.2 mmHg, respectively, and PVoc was reduced by an average of 0.47 microliters (51%) in both series 1 and 2. These effects of RBA may be interpreted as a depressing influence on ocular circulation. 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)