Background: Fluid absorption and associated electrolyte derangement is an inevitable complication of Transuretheral Resection of Prostate (TURP) and Percutaneous Lithotripsy (PCNL) irrigation during transurethral resection of prostrate and PCNL. Aim: to analyse changes in serum electrolytes, Lactate Dehydrogenase (LDH) and acid base status, and to evaluate their role as early predictors of clinical and haemodynamic changes following continuous irrigation during transurethral resection of prostrate and PCNL.