To the Editor:
We read with interest the study by Yee et al.  comparing patient movement during retrobulbar block placement with methohexital or alfentanil administration. Although we too have found alfentanil to be useful for this purpose, two questions are raised.
No mention was made of the needle used. As the 23-gauge Atkinson needle (Visitec Registered Trademark, Sarasota, FL) produces a greater stimulus on skin penetration compared with local infiltration and advance of a smaller, sharper needle, the choice of needle influences alfentanil dose titration. The elderly ophthalmic surgical population is usually more sensitive to respiratory and cardiovascular depressant effects of alfentanil, and we are surprised that the 1500 micro gram used in the series (20 micro gram/kg times weight) did not have significant respiratory depression and that no mention was made of hemodynamic variables.
We have achieved satisfactory patient comfort and tolerance of the block without significant respiratory or cardiovascular compromise with titration of 250- to 750-micro gram doses of alfentanil (5-10 micro gram/kg). Contrary to the concern of patient movement causing complications, earlier awakening with smaller doses of an anesthetic or opioid would assist in differentiating problems such as brainstem anesthesia or pain from retrobulbar hemorrhage.
E. G. Pivalizza, MBChB, FFA
D. C. Abramson, MBChB, FFA
Department of Anesthesiology, Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030
1. Yee JB, Schafer PG, Crandall AS, Pace NL. Comparison of methohexital and alfentanil on movement during placement of retrobulbar nerve block. Anesth Analg 1994;79:320-3.