The effect of ondansetron and dexamethasone on reduction of post operative nausea and vomiting (PONV) in laparoscopic cholecystectomy

INTERVENTION: Dexamethasone (8 mg, increased volume to 2 ml) before induction of anesthesia Intervention 1: Dexamethasone (8 mg, increased volume to 2 ml) before induction of anesthesia. Intervention 2: Ondansetron(4mg, increased volume to 2 ml) before induction of anesthesia. Intervention 3: Normal Saline, 2 ml, before induction of anesthesia. Normal Saline, 2 ml, before induction of anesthesia Ondansetron(4mg, increased volume to 2 ml) before induction of anesthesia Prevention CONDITION: Nausea and vomiting after laparoscopic cholecystectomy. ; Vomiting following gastrointestinal surgery Vomiting following gastrointestinal surgery PRIMARY OUTCOME: Nausea after surgery. Timepoint: In the recovery room after surgery‐6 and 24 hours after surgery. Method of measurement: Observation and history taking of patients, relatives and nursing staff. Vomiting after surgery. Timepoint: In the recovery room after surgery‐6 and 24 hours after surgery. Method of measurement: Observation and history taking of patients, relatives and nursing staff. INCLUSION CRITERIA: INCLUSION CRITERIA: Candidate for laparoscopic cholecystectomy, ASA class I‐II, age 15‐80 years Exclusion criteria: Gastroesophageal reflux ‐ Severe obesity ‐ difficult airway