A Comparison Of Respiratory Dynamics Between Pressure Controlled Ventilation And Volume Controlled Ventilation In Children Under Six-year-old Undergoing General Anesthesia With Laryngeal Mask Airway-Ambu

Objective: Laryngeal mask, which plays an important role for pediatric respiratory function, became a common tool for ventilation during general anesthesia in children because of its simple operation and convenience to maintain ventilation. Compared with adults, it is more often for children to present hyperresponsiveness such as cough, apnea and laryngospasm when using of laryngeal mask airway. The infants under 12 month are even more likely to have a mask shift and airway obstruction for their special physiology and anatomy. It should be monitored seriously as the higher incidence of hypoxemia in children. Mechanical ventilation is one of the important methods of respiratory management. Each traditional mechanical ventilation models have advantages and disadvantages. Pressure controlled ventilation was the most frequently used mode in pediatrics in the past 40 years. But there is still little strong clinical evidence to find out which kind of ventilation method is the most superior. The purpose of this research was to compare the influence of both pressure controlled ventilation and volume controlled ventilation on respiratory dynamics by using Continuous Airway Monitoring of Side Stream Spirometer for children under 6-year-old who have general anesthesia with laryngeal mask airway-Ambu during mechanical ventilation, and to find a more safe and effective way with laryngeal mask in pediatric anesthesia.Methods: 100 pediatric patients with hypospadias, scheduled as ASA I or II, were divided into two groups: Group A(aged 1-6, n=60) and Group B(under 1 year, n=40). Each group were further divided into two groups randomly: Pressure controlled ventilation(group P) and Volume controlled ventilation(group V). After intravenous anesthesia induction, LMA-Ambu was inserted. Parameters for respiratory mechanics including tidal volume(VTin/ex), peak inspiratory pressure(PIP), plateau airway pressure(Pplat), mean airway pressure(Pmean), positive end expiratory pressure(PEEP), peak expiratory flow(PEF) and Et CO2 were recorded at the scheduled time points.Expiratory resistance(Re) and work of breathing(WOB) were also calculated. Meanwhile, the hemodynamic changes and complications were recorded.Results: In Group A, PIP was higher(P<0.05) in group V compared with group P at all scheduled time points; In Group B, at the time point of 20 min and 30 min, PIP in group V was significantly higher than that in group P(P<0.05); no complication was observed in each groups.Conclusion: There are some differences in respiratory dynamics indexes between pressure controlled ventilation and volume controlled ventilation in Children under 6-year-old when having general anesthesia with laryngeal mask-Ambu. The pressure control of ventilation provide lower PIP. And in infants, the PIP in volume control ventilation group is significantly higher than that in pressure controlled ventilation group over time.