Postoperative nausea and vomiting (PONV) are common and distressing symptoms after surgery under general anesthesia. Despite advances in balanced anesthesia in recent decades, PONV can result in delayed discharge from the Post-Anesthesia Care Unit (PACU) recovery room, unexpected hospitalization and increase in medical costs.~The latest class of antiemetic for the prevention and treatment of PONV are the serotonin receptor antagonists (ondansetron, granisetron). These antiemetics do not have the negative effects of the older generations. Headache and dizziness are the main adverse effects of the serotonin receptor antagonists in the dosages used for PONV .~The FDA approved dose for the prevention of PONV is 1mg. This is based on a dose range study from Wilson and associates in which 0.1, 1.0, and 3.0 mg were associated with risk ratios for postoperative vomiting. The majority of studies on granisetron suggest that 3mg is superior to 1mg for the prevention of PONV, but those were published by a single center and there have been serious concerns about the validity of the data. In previous studies done on elective open abdominal surgery or vaginal hysterectomy but not in strabismus ophthalmic surgeries.~The ocular surgery associated with the highest incidence of PONV is strabismus surgery up to 85%. Vomiting after surgery is more likely 2-8hours than immediate postoperatively. Strabismus is a day case procedure and thus participants have to cope with emesis in the recovery room, or when traveling, or at home.~In this study, investigators compared two doses of granisetron in strabismus ophthalmic surgeries under general anesthesia
Investigators aim to determine the optimal dose of granisetron in strabismus ophthalmic surgeries under general anesthesia to prevent postoperative nausea and vomiting