RESUMO
Chest wall in children is more compliant, slow twitch muscle fibers are less than adults and the alveolus are smaller hi size and lesser hi number. Airways are more expandable and smaller hi diameter. In the other hand the inhalational anesthetics can cause respiratory depression and rapid shallow ventilation. These changes can cause microatelectasia, low respiratory system compliance and increase hi work of breathing. Controlled ventilation probably will prevent these events. This study is going to compare behaviors of respiratory system under inhalational anesthesia. In a clinical trial, 60 pediatric patients between 6 months to 6 years of age, ASA I and II, who were candidates of elective surgery on extremities and lower abdomen, entered to study. Patients were randomly allocated hi two groups of spontaneous and controlled ventilation. In the first group hihalational and in the second group intravenous inductions was performed. Both groups were given halo thane [0.8-1%] hi a 50% mixture of N[2]O and O[2] for maintenance of anesthesia. HR, RR, BP, SPO[2] and T before hiduction and all of these plus EVT and peak and plateau APs, 5 minutes after induction and every 15 minutes thereafter were measured and dynamic and static compliance were calculated by using measured data. Data was analyzed by ANOVA, T student and Chi square tests. Patients hi spontaneous ventilation group had significantly more RR and EtCO[2] and less awakening time [p<0.05].Total mean of HR, SBP, DBF, SPO[2], T, PIP, PltlP, dynamic and static compliance after hiduction of anesthesia had no statistical differences between the two groups. There are no constant significant differences between the two groups hi respiratory system compliance, airway pressures and T and this study can not prove the development of significant changes hi respiratory system indices between the two groups. Thus microatelectasis [if developed] is not clinically important during less than one hour surgeries