Comparative study of electrolytes and metabolic changes during percutaneous nephrolithotomy: spinal vs. general anaesthesia

Background: Percutaneous nephrolithotomy (PCNL) is a common surgery for renal stones and it can be performed under spinal and general anaesthesia. There is always a debate upon the superiority of one of the above technique over other. This study was undertaken to study the metabolic changes associated with the use of above techniques. We also studied the blood loss associated with them. Methods: 60 patients of either sex, aged between 25 to 60 years belonging to ASA physical status I or II undergoing PCNL were divided randomly into two groups and they received spinal (SA) and general anaesthesia (GA) as per standard protocol and study parameters were evaluated. Results: Blood pressure was lower and heart rate was higher in SA group compared to GA group. Changes in pH, bicarbonate, serum sodium, serum potassium and serum lactate were insignificant. Blood loss was report to be lower in SA group. Conclusions: In both the groups, patients were haemodynamically stable throughout the surgery and both the techniques were safe regarding hemodynamic changes and no significant advantage or disadvantage exists between the two. In both the groups there was a trend towards metabolic acidosis with increased lactate levels but it was not clinically significant with any of the anaesthetic technique. No changes were seen in electrolytes levels (Na and K) in any of the groups. Spinal anaesthesia was associated with lesser amount of blood loss and need for post-operative blood transfusion as compared to general anaesthesia.