Immersion anesthesia for extracorporeal shock wave lithotripsy. Review of two hundred twenty treatments.

Two hundred twenty extracorporeal shockwave lithotripsy (ESWL) treatments at the New York Hospital-Cornell Medical Center between September, 1984, and April, 1985, were reviewed with respect to anesthetic management. One hundred seventy-four treatments (79%) were performed under a regional anesthetic technique (RA), either with an indwelling epidural catheter (155 treatments), or with a single spinal injection (19 treatments). Forty-six treatments (21%) were performed under general anesthesia (GA). Ninety per cent of the patients were classified as ASA I or II. Hypotension during treatment, defined as blood pressure falls greater than 20 per cent of baseline mean arterial pressure, was recorded with 19.5 per cent of the regional anesthetic treatments (18.7% of the epidurals and 26.3% of the spinals) and 13.0 per cent of the general anesthetic treatments. Blood pressure falls were larger in the regional group than in the general group. The average recovery room stay was longer for the bupivacaine (0.25-0.5%) epidurals and the tetracaine (0.4%) spinals (252 min and 212.1 min, respectively) than for the lidocaine (1.5-2.0%) epidurals and the general anesthetics (101.7 min and 102.1 min, respectively). General anesthesia, with controlled ventilation, was advantageous in minimizing renal excursion and stone movement during treatment. Yet, in appropriately selected and sedated patients, regional anesthesia with continuous lidocaine epidural techniques was found to provide acceptable anesthesia for patients undergoing ESWL.