عوامل خطر تهوع و استفراغ پس از بي هوشي عمومي با اكسيد ازت

Risk factors of postoperative nausea and vomiting following the use of N20 in general anesthesia

Background : PONV has been variously reported to occur in up to 92% of the patients who receive N20 during general anesthesia. However , it is not yet clear that when , why , in whom and under which cir umstances does N20 induce nausea and vomiting. Objective : To determine the incidence rate of PONV after the adminstration of N20 according to age , sex , anatomical site of the operation , duration of anesthesia and history of not on sickness in order to define the main rick factors. Methods • 100 patients who were scheduled for surgery in four of the teaching hospitals of Rasht city were sequentially and non-randomly studied. Except N20 , all other PONY inducing factors as described in the Literature , were defined as exclusion criteria. All patients received general bbalanced anesthesia with the same regimen including N20 in 50% to 70% concentrations. No antiemetics were administered. The occurence of PONV was recorded for six hours after the termination of anesthesia. Findings : PONY (Nausea/Vomiting/both) occurred in 55% of the patients. In the 15-i5 years age group 50.8% in the 36-55 years age group 62.1% among females 63.2% and in males 44.2% experienced PONY. 80% of the patients with a history of motion sickness and 46.7% of those without it suffered PONY Considering the anatomical site of the operation the highest incidence (63.9%) of PONV was seen in the case of lower abdomen and pelvic operations. Incidence of PONV in-groups with different length of anesthesia was almost the same. Conclusion : Women , patients with a history of motion sickness and those undergoing a lower abdomen or pelvic operations are more prone to PONV following the use of N20. Therefore they require more scrutinising postoperative care till a proper alternative A found for N20.