Acute Effects of Full Urinary Bladder and Full Caecal Urinary Reservoir on Regional Renal Function

Abstract

Scintillation camera renograms were recorded in six patients without a history of bladder function disturbances and in eight patients with caecal urinary reservoir. Each patient was studied once with empty bladder/reservoir and once with full bladder/reservoir. Renograms were obtained from parenchyma, pelvis and whole kidney. Time was measured from injection of isotope to peak of the renogram curve (T_max) and to the point corresponding to the centre of gravity of the area under the curve (T_g). A full reservoir gave longer T_max and T_g for both parenchyma and pelvis than an empty reservoir. With full bladder the only significant change was T_g increase for renal pelvis. In the patients with full caecal reservoir, the elimination of radioisotope from the renal pelvis was significantly slower, reflected as longer T_max and T_g, than in the subjects with full bladder. In comparisons between empty and full bladder/reservoir, T_g permitted clearer separation between the groups than did T_max. The higher T_max and T_g values for full than for empty reservoir indicated obstruction to urinary flow and could be ascribed to the high intrareservoir pressure. Regularly occurring pressure waves with amplitudes of 30-65 cm H₂O were recorded in the reservoirs, sometimes reflected as transient increases in radioisotope activity in the renograms. In some patients the two kidneys differed considerably in their response to a full urinary bladder or reservoir. The cause may have been difference in the dynamics of the two ureterovesical junctions or of the ureterointestinal anastomoses. It is concluded that the full urinary bladder exerts little influence on renal parenchymal and pelvic function, as measured by scintillation camera renography, but that a full caecal urinary reservoir considerably slows the passage of the radioisotope.