A prospective comparative study of haemodynamic, electrolyte, and metabolic changes during percutaneous...

To report the haemodynamic, electrolyte, and metabolic changes of a prospective clinical trial comparing minimally invasive percutaneous nephrolithotomy (MPCNL) with percutaneous nephrolithotomy (PCNL) for renal stones.

In all, 71 patients who had undergone MPCNL (37) or PCNL (34) were prospectively assessed. Heart rate and arterial blood pressure were monitored, and samples for electrolyte estimation and arterial blood gas analysis were drawn at the start, 30th, 60th, 90th, and 120th min of irrigation and 24 h later after both procedures.

In the PCNL group, no significant changes occurred in heart rate, arterial blood pressure, electrolytes, and pH. In the MPCNL group, heart rate, arterial blood pressure, and serum sodium levels kept stably during and after irrigation; the decrease in potassium levels was found from the 30th to 120th min of irrigation and did not recovery until 24 h later after operation (P < 0.05), but the potassium levels was normal during the entire observation period; the increase in Cl(-) levels was noted at the 120th min of irrigation (P < 0.05); there was a decreasing trend of pH from the start to the 120th min of irrigation (P < 0.05) and 24 h later after operation this trend attenuated (P < 0.05); the changes in base excess levels were in accordance with those in pH levels.

Although haemodynamic and electrolyte changes remains stable, a trend towards metabolic acidosis is obvious as the irrigation time goes by during MPCNL compared with PCNL. Therefore, arterial blood gases should be monitored during and after MPCNL in patients with prolonged irrigation time.