Renoprotective effect of mannitol infusion during extracorporeal shock lithotripsy.

OBJECTIVE To evaluate the role of mannitol infusion in preventing or ameliorating renal injury that accompanies shock wave lithotripsy as measured by changes in resistive index (RI). METHODS Between February and September 2006, 38 patients (28 men and 10 women) underwent extracorporeal shock wave lithotripsy (ESWL) for radiologically documented renal stones in The Surgical Specialties Hospital ESWL unit, Baghdad, Iraq. The 38 patients aged 20-50 years with renal stones of 10-20 mm size, scheduled for ESWL therapy, were divided into a control group (20 patients) and mannitol group (treatment group of 18 patients). All patients had their renal RI measured before ESWL, immediately after ESWL, then 3 and 7 days later. While patients in the mannitol group were given 0.5 gm/kg mannitol infusion during lithotripsy, the control group patients were given nothing. Changes in renal RI in both groups were evaluated statistically within the group and between the 2 groups. RESULTS A significant rise in renal RI was found in the control group immediately after ESWL, then 3 and 7 days after. It increased from an initial value of 0.5875 to 0.6500, 0.6300, and 0.6245. The mannitol group showed fewer changes, yet still significant from 0.5850 to 0.6061, 0.6022, and 0.5967. This elevation of renal RI in the control group when compared to the mannitol group was statistically significant. CONCLUSION Mannitol has a renoprotective function when given during ESWL, as evidenced by the statistically significant reduction in renal RI.