Effect of N2O on nausea and vomiting via intraabdominal pressure.

BACKGROUND AND OBJECTIVE: In this study we aimed to investigate whether there is an effect of N2O on postoperative nausea and vomiting (PONV) via intraabdominal pressure (IAP). METHODS: A total of 40 patients with risk class ASA I-II and age ranging between 20 and 50 years were enrolled in the study. The patients were monitored for electrocardiography (ECG), peripheral oxygen saturation (SpO2), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), end-tidal carbon dioxide (ETCO2) and body temperature. IAP was measured by a central venous pressure manometer placed in the urine catheter. Heart rate (HR), SpO2, SBP, DBP, MBP, ETCO2, body temperature and IAP were measured before the induction of anesthesia and every 10 minutes throughout the operation. Nausea and vomiting were questioned at the first and second postoperative hours. The patients were randomly grouped into two groups. Induction in both groups was provided using 2 mg/kg propofol, 2 µg/kg fentanyl and 0.1 mg/kg vecuronium, and endotracheal intubation was performed. The maintenance of anesthesia was provided by 40 % O2 + 60 % N2O, 1-2 % sevoflurane and 50 µg fentanyl + 2 mg vecuronium every 45 minutes in the first group. In the second group, 60 % dry air was used instead of 60 % N2O. RESULTS: There was no significant difference in terms of HR, SpO2, SBP, MBP, ETCO2, body temperature, nausea-vomiting and IAP. CONCLUSIONS: In conclusion, we think that N2O usage during the general anesthesia in patients without intraabdominal problems may increase IAP level for some degree whereas it does not increase PONV. In addition, N2O usage does not change ETCO2 values (Tab. 3, Fig. 3, Ref. 32).