The aim of the study is to compare the impact intravenous sedation versus general anesthesia on the efficacy of stone fragmentation in extracorporeal shock wave lithotripsy treatment.

The newer lithotriptors were reported to be less efficacious than the Dornier HM3 lithotriptor; and it is not clear the reason why there is decrease in efficacy of the new lithotriptors. Is it due to their small focal point or to increased patient movement while under intravenous sedation.When the patients get sedated then it will be difficult to control their respiratory movements. Retrospective comparisons suggest that intravenous may facilitate earlier discharge if no manipulation of the airway was done; but they are often associated with pain, hypoxemic respiratory episodes and disruptive movements during lithotripsy Instead of intravenous sedation, general anesthesia offer pain free procedures, no movement of the patient and controlled movement of the respiration leads to stable position of the urinary stones and receives persistent shock wave energy on to the stone bringing about better and early fragmentation. Hence we work on the hypothesis that the new generation shock wave lithotripters have a small focal point, every movement of the stone during the respiration or patient movement, will take the stone out of the focus and there results in loss of shocks leading to lithotripsy failure and use of more fluoroscopy for refocusing the stone.

Thus we think the proper choice of anesthetic technique will improve the efficacy of stone fragmentation in shock wave lithotripsy treatment at least in those who are obese and suffers from occult sleep- apnoea syndrome

Inclusion Criteria:

1. Renal or upper ureteral stone of less than 2cm
2. A.S.A Grade 1.2.3
3. Age above 18 years

Exclusion Criteria:

1. Mid or lower ureteral stones
2. Bilateral renal stones
3. Multiple stones
4. Use of regional anesthesia
5. Coagulopathies (thrombocytopenia, anticoagulation drugs)
6. Suspected or documented difficult intubation
7. History of chronic opioid abuse