Conditions: Hemorrhoids Pain
Keywords: hemorrhoids hemorrhoidectomy S (+) ketamine pain
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 83
Healthy volunteers: no

Brief summary:
The purpose of this study is to determine whether the use of perioperative intravenous S (+) ketamine reduces the amount and degree of postoperative pain.

Furthermore the purpose of this study is to determine whether the use of perioperative intravenous S (+) ketamine effects cognitive function in the early postoperative period.

Detailed description:
The mechanism of development of postoperative pain is complex. Central and peripheral sensitization are playing an important role and this can lead to postoperative hypersensitization. Several studies have shown, that S (+) ketamine can be effective to reduce sensitization and postoperative pain. Ketamine (2-O-chlorophenyl-2-methylamino cyclohexanone) is a N-Methyl-D-Aspartat (NMDA) receptor antagonist. S (+) ketamine has a four times stronger affinity to the NMDA receptor compared to R (-) ketamine. The duration of action for S (+) ketamine is shorter than R (-) ketamine and it has fewer side-effects.

The purpose of this study is to compare the analgetic effect of pregabalin and placebo used in the perioperative period.

The hypothesis is that perioperative intravenous S (+) ketamine gives significant better analgesia than placebo without effecting cognitive function.

The study is including patients undergoing hemorrhoidectomy.

Arms:
arm 1: Saline 0,9% arm 2: None

Interventions: intervention 1: S (+) Ketamine intervention 2: Placebo
Intervention descriptions: intervention 1: 0,35 mg/kg bolus after induction of anaesthesia; 5 ug/kg/min. continuous until the end of surgery intervention 2: isotonic saline

Protocol document: