The Transparency of Irrigation Fluids Used in Endoscopic Surgery

Transurethral surgery has been traditionally done using the nonelectrolyte, isotonic 1.5% glycine solution as irrigation fluid. The emergence of modern technologies, which can be applied with electrolyte solutions, such as bipolar resection and LASER evaporation, as well as the worry of transurethral resection (TUR) syndrome have driven urologists away from glycine toward the use of physiologic solution. Differences in the transparencies of these fluids have not been studied.

The ability to resolve two bars at 1 mm apart using a 30° cystoscope lens immersed in different solutions was studied. Physiologic solution, distilled water (DW), and 1.5% glycine solutions containing increasing concentrations of blood, from 0.5% to 2%, were tested. Solutions containing 2% blood were inspected with magnification and microscopy.

One-millimeter resolution was reached in as much as 2% blood in 1.5% glycine solution and as much as 1% blood in DW, but in none of the blood-saline solutions. Magnified and microscopic views of 2% blood solutions showed an even distribution of red blood cells (RBCs) in physiologic solution, clumps of RBCs in 1.5% glycine, and an almost complete hemolysis in DW.

Glycine solution increases the transparency compared to physiologic solution or DW owing to the clumping of RBCs. When the risk of TUR syndrome is low, as in resection of bladder tumors or small prostates, we propose that 1.5% glycine solution should be preferred over saline, owing to its improved visibility.