Intrathecal Atropine Versus Intravenous Metoclopramide for Prevention of Nausea and Vomiting During Caesarian Section Under Spinal Anesthesia

Patients After obtaining the approval of the Mansoura Faculty of Medicine Institutional Research Board (MFM-IRB) and registration with ClinicalTrials.gov, this prospective double blind randomized study will be conducted in the next 6 months on 100 pregnant women undergoing elective CS in obstetric surgery unit in Mansoura University Hospital, Mansoura, Egypt. A written informed consent will be taken from each patient selected to participate before inclusion in the study.

Inclusion criteria Patients with ASA physical status class I or II; indications for CS other than fetal or maternal pathology and surgery scheduled for within 4 days of physiological term will be included in this study.

Exclusion criteria Patients with any of the following criteria will be excluded from the study: 1) age < 20 or > 35 years; 2) height < 150 or > 180 cm; 2) body mass index (BMI) >35 kg/m2; 4) active labor or emergency CS; 5) emesis gravidarum; 6) multifetal pregnancy; 7) fetal distress; 8) associated medical problem with pregnancy (as hypertension, diabetes mellitus, hepatic impairment or renal impairment);9) obstetric problem (as placenta previa or placental abruption); 10) contraindication for central neuraxial block; 11) history of adverse reaction to any study medication; 12) history of antiemetic drug use; or 13) refusal to undergo regional anesthesia.

Methods All patients participating in the study will be randomly divided into two groups; atropine group and metoclopramide group. The randomization will be simple and balanced (1:1) and will be carried out by a nurse through sealed, unlabeled, opaque envelopes containing computer-generated random numbers. The participants, caregivers and investigators will be blinded to group assignment. Patients in the atropine group will receive IV study solution which is 2 ml saline 0.9% as a placebo + intrathecal study solution which is a premised solution of 2.5 ml of 0.5% hyperbaric bupivacaine, 25 μg fentanyl and 100 μg of a 1 mg/ml preservative-free atropine sulfate solution. Patients in the metoclopramide group will receive IV study solution which is metoclopramide 10 mg in 2 ml + intrathecal study solution which is a premised solution of 2.5 ml of 0.5% hyperbaric bupivacaine, 25 μg fentanyl and 100 μg of preservative-free saline 0.9% as a placebo.

All participants will be instructed to stop oral intake 8 hours before surgery, but they will be allowed to drink moderate amounts of water and juices until 6 hours before surgery. Anesthesia protocol will be standardized in all patients. On arrival of the patient to operative theatre, intravenous (IV) cannula will be inserted and IV infusion of Ringer's acetate (8 ml/kg) will be given over about 20 minutes as a fluid preload before anesthesia. Patients will receive the IV study solution (according to their allocation) 15 minutes before start of anesthesia procedures. The spinal anesthesia will be performed in sitting position under strict aseptic condition. The anesthesia will be given at the level of L2-L3 or L3-L4 with a 25-gauge whit acre needle. Injections will be made using three separate syringes. Patients will be placed in a supine position immediately after the end of injections. A left lateral posture will be applied to all patients.