Study Of Monitoring The Volume Of Irrigating Fluid Absorbed With Ethanol Method During Minimally Invasive Percutaneous Nephrolithotomy

Background and ObjectivePercutaneous nephrolithotomy (PCNL) is an important component of endourology. Lahme S performed PCNL by F14～F16 percutaneous channel in 2001 and named it minimally invasive percutaneous nephrolithotomy (MPCNL).Wu Kai-jun and others improved and innovated MPCNL in technical details to make it more simple and practical,and expand its area of application. Large amounts of irrigating fluid are used during MPCNL and fluid absorption is associated with complications. The objective of this study is to evaluate the necessity of monitoring the volume of irrigating fluid absorbed during MPCNL and explore the ways to reduce the absorption of irrigating fluid by monitoring the amount of irrigating fluid absorbed during MPCNL with ethanol method. Patients and MethodsIn this study 20 patients with calculus of renal or superior ureter from 2008/11 to 2009/1 were collected.They all underwent minimally invasive percutaneous nephrolithotomy.0.9% saline containing 1% ethanol was used as the irrigating fluid, the ethanol concentration in the patient's exhaled breath was measured every 10 minutes during the procedure. The volume of irrigating fluid absorbed was calculated by the formula below: Abstot=Σ(2140+3430 x EB-ethanolIi)×ΔEB-ethanol+(44+806×EB-ethanolIi) (Abstot:the total absorption during the operation,EB-ethanolI:ethanol concentration at beginning of 10 minutes period,ΔEB-ethanol:change in ethanol concentration during a 10 minutes period).Heart rate and mean arterial pressure were recorded during operation. Hemoglobin concentration, serum electrolyte, carbon dioxide-combining power, serum creatinine and blood urea nitrogen were measured before and after operation. Factors thought to affect the amount of irrigating fluid absorbed were studied, including the amount of irrigating fluid used, the duration of operation, and the intrapelvic pressure.ResultsAll the operations completed successfully. Fluid absorption was observed in all patients.The volume of irrigating fluid absorbed was 50.21-685.02ml, and the mean was 202.47±145.81 ml.There was no statistical significant difference in heart rate, mean arterial pressure, serum Na+,K+,Cl-and serum creatinine between pre-and postoperation (P>0.05),but the differences in hemoglobin concentration, carbon dioxide-combining power and blood urea nitrogen between pre-and postoperation were statistically significant (P<0.05).The volume of irrigating fluid absorbed in patients with total time of the intrapelvic pressure higher than 30mmHg >10min, or the amount of irrigating fluid used>10000ml, or the duration of operation>1h was more than the others significantly (P<0.05). ConclusionsNot all the patients undergoing MPCNL need monitoring the volume of irrigating fluid absorbed during the operation routinely. The ethanol method is safe, valid, simple, convenient, and suitable for patients with compromised cardiorespiratory or renal satus, who were more likely to develop volume overload because of fluid absorption. Avoiding high pressure in renal pelvis, shortening operation time, and reducing the amount of irrigating fluid used help reduce the amount of irrigating fluid absorbed.