Effects of fluid absorption following percutaneous nephrolithotomy: Changes in blood cell indices and electrolytes

Effects of fluid absorption on hematological profile in the immediate postoperative period in patients undergoing percutaneous nephrolithotomy (PCNL) have not been given due importance. Considering the limited number of studies available, we conducted this study to evaluate the changes in hemodynamics, complete blood count (CBC), and electrolytes in patients undergoing PCNL using normal saline for irrigation in the prone position. Furthermore, we evaluated the common factors known to affect the absorption.

Forty American Society of Anesthesiologist Class I or II patients aged 18-65 years were recruited who underwent PCNL under general anesthesia. Heart rate, blood pressure (BP), CBC, and serum electrolytes were recorded preoperatively and just before extubation and compared using the Student's t-test. Correlation of these changes with height and total volume of irrigating fluid, total time of irrigation, duration of operation, and total intravenous fluids administered intraoperatively were performed using the Pearson's correlation coefficient.

There was a statistically significant fall in mean hemoglobin (12.5 g/dL to 11.5 g/dL), packed cell volume (38.6%-35.6%), platelet count (2.9 × 10⁵ cells/μL to 2.5 × 10⁵ cells/μL), and sodium ion concentration (Na⁺) (138.9 meq/L to 137.7 meq/L) in the immediate postoperative period as compared to that of the preoperative values. Rest of the blood indices and electrolytes did not show any significant change. There was a significant rise in postoperative heart rate and BP. Postoperative systolic BP showed a significant positive correlation with the total volume of irrigating fluid. No significant correlation was observed with height and total time of irrigation.

This study reveals that there is a significant fall in hemoglobin and Na⁺ during PCNL in the immediate postoperative period. Only, total volume of irrigating fluid and total duration of surgery had a significant correlation with blood cell indices.