1. 80 ASA I-II patients undergoing elective laparoscopic or proctologic surgery received at induction of general anaesthesia a single i.v. bolus dose of either ketamine 0.15 mg/kg or placebo (0.9% NaCl).

2. The following 50 proctologic procedures were performed using TLA as day surgery cases: perianal vein thrombectomy (n=15), subanodermal fistula resection (n=7), anal polyp resection (n=7), fissurectomy (n=6), perianal abscess revision (n=6), excision of anal skin tags (n=3), hemorrhoidectomy for thrombosed piles (n=3), intersphincteric fistula extirpation (n=1), pilonidal sinus (n=1), and perianal tumor excision (n=1).