The immediate success and flow of a newly constructed arteriovenous fistula is mainly dependent on arterial inflow and subclavian venous flow. An arterial inflow rate of 40 ml/min or more and subclavian venous flow rate of 400 ml/min or more measured by colour flow duplex imaging prior to the operation will be associated with better outcomes, and therefore the use of colour flow duplex imaging is warranted during the evaluation of patients who are candidates for an arteriovenous fistula operation.

Purpose: To investigate the blood flow changes in ophthalmic artery with color Doppler ultrasonography after strabismus surgery. Methods: Twenty eyes of 19 patients who underwent recession or resection surgery on two horizontal rectus muscles in 1 eye were examined using color Doppler ultrasonography preoperati vely and 1 week and 1 month postoperatively. Measurements from both eyes of 1 6 age- and sex-matched normal subjects served as control data. The systolic maximum velocity, mean velocity, end-diastolic velocity, pulsati I ity index, and resistance index of the ophthalmic artery were determined. The Mann-Whitney U test was performed for comparison of the control and study group preoperatively for any hemodynamic parameter. Statistical comparison of the preoperative and postoperative measures in the study group was performed with Friedman's two-way analysis of variance. Results: No difference (P>.05) was observed preoperatively between the study and control groups for any hemodynamic parameter in the ophthalmic artery. Although the ophthalmic artery showed a slight increase in systolic maximum velocity 1 month postoperatively, there were no statistically significant differences (P>.05) in velocities or resistance in the ophthalmic artery at any interval. Conclusion: Two horizontal rectus muscle operations in a previously unoperated eye do not cause significant hemodynamic changes in the ophthalmic artery. However, further studies are needed to obtain more information about the effect of multiple vertical rectus muscle operations on the blood flow parameters of the ophthalmic artery. Journal of Pediatric Ophthalmology and Strabismus 2000;37:94-100.