CALCIUM HOMEOSTASIS DURING IV INFUSION OF 1.5-PERCENT GLYCINE IN ANESTHETIZED PIGS

We have examined changes in plasma concentrations of calcium in seven anaesthetized pigs during i.v. infusion of irrigating fluid containing 1.5% glycine. Volumes infused were 875 ml at 20 min (22 ml kg(-1)), 1 475 ml at 40 min and 2075 ml at 60 min (75 ml kg(-1)). Plasma concentr ations of sodium decreased from 134.5 (SD 3.4) to 112.8 (6.7) mmol lit re(-1) at 60 min and correlated with the volume of glycine infused (r( 2) = 0.73; P < 0.0001). Changes in total calcium concentrations were n ot statistically significant. A decrease in ionized calcium concentrat ion was observed at 40 min (1.12 (0.05) vs 1.24 (0.04) mmol litre(-1); P < 0.05) and reached 1.11 (0.05) mmol litre(-1) at 60 min (P < 0.01) . However, when corrected for pH, this decrease was not statistically significant. These results suggest that changes in plasma concentratio ns of sodium rather than changes in calcium homeostasis are probably m ore important in the development of transurethral prostatic syndrome.