Dilutional hypocalcaemia from urological irrigating fluids.

A normal serum calcium concentration is essential for cardiovascular and muscular function. The hypocalcaemia-inducing potential of urological irrigating fluids was studied in 7 young men and in 10 prostatectomy patients. A total of 48 intravenous infusions of 1,000 ml of various irrigating fluids showed consistently that dilution of the serum calcium concentration occurs. The magnitude of the dilution was in between that recorded for albumin and for sodium. The free calcium concentration, however, correlated closely with the serum sodium level. These results suggest that dilutional hypocalcaemia can be expected to coexist with hyponatraemia in patients who develop the transurethral resection syndrome.