Comparison of the effect of the ondansetrone 4 mg in combination with dexamethasone 4 mg and dexamethasone 8 mg on post operative nausea and vomiting after elective cesarean section under spinal anesthesia

Determination the effect of low dose of dexamethasone on prevention of nausea and vomiting after cesarean section

A randomized, double-blind, placebo controlled clinical trial.135 Patients will randomly allocated to 3 groups using balanced block randomization.The study is phase 3

The site of research is Yas Hospital.After approval by the Ethics and Clinical Studies Committee of Tehran University of Medical Science the investigation will be started.Informed consents will be obtained from all of the patients.The study drugs are being prepared by a person who is not subsequently involved in the research and will be packed in an envelope that the patient code has been written on it and just before spinal anesthesia will be opened and injected .The anesthesiologist of operation room and all operation and recovery room nurses and the nurses responsible for the questionnaire are unaware of the type of drug and the patient group. Incidence of nausea and vomiting will evaluate intraoperatively, in the recovery room and 3,6,12,24 hrs postoperatively.

Inclusion criteria;Female 18-45 yrs,ASA class 1-2, uncomplicated pregnancy,elective cesarean section Exclusion criteria:History of motion sickness and severe morning sickness, symptoms of cardiovascular ,hepatic,renal and psychotic diseases,unwillingness to work with scholars

Just before spinal anesthesia group 1: 4 mg ondansetron plus 4 mg dexamethasone with 3 cc volume , group 2: 4 mg ondansetron plus 8 mg dexamethasone with 3 cc volume and group 3: 4 mg ondansetron and normal saline with 3 cc volume will receive intravenously.

Incidence of nausea and vomiting after cesarean section

Patients will randomly allocated to 3 treatment groups using balanced block randomization.There are 3 interventions therefore the blocks will contain 6 letters(AABBCC) and we will have 22 blocks in total (135/6=22). We can have twenty block models that they will be arranged in random order and finally the 2 next blocks will select randomly among that 20 models and will be added.

The study medications are prepared by an anesthesiologist who does not otherwise participated in the study and then are enveloped and sealed and patient′s code are recorded on it. The envelopes will open in operation room just before spinal anesthesia by an anesthesiologist who is blinded to patient′s study group and type of solution and then will inject intravenously. All of the nurses and patients are blinded to the type of solution and to the patient′s study group allocation.also the nurse who fill the questionnaire