摘要
Continuous improvements in perinatal care have resultedin increased survival of premature infants.Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease(CLD) or bronchopulmonary dysplasia.Strategies to minimize the risk of lung injury have been developed and include improved antenatal management(education,regionalization,steroids,and antibiotics),exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support.The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patientventilator asynchrony that is associated with poor outcome.Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur.This has led to the development of new ventilation modes including neurally adjusted ventilatory assist(NAVA).This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity(Edi) and transmit it to trigger the ventilator in synchrony with the patient's own respiratory efforts.This permits the patient to control peak inspiratory pressure,mean airway pressure and tidal volume.Back up pressure control(PC) is provided when there is no Edi signal and no pneumatic trigger.Compared with standard conventional ventilation,NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants.NAVA is safe mode of ventilation.The majority of studies have shown no significant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage,pneumothorax,or necrotizing enterocolitis when compared to conventional ventilation.Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive.Most previous studies and trials were not sufficiently large and did not inclu
Continuous improvements in perinatal care have resulted in increased survival of premature infants. Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease （CLD） or bronchopulmonary dysplasia. Strategies to minimize the risk of lung injury have been developed and include improved antenatal management （education, regiona-lization, steroids, and antibiotics）, exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support. The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patient-ventilator asynchrony that is associated with poor outcome. Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur. This has led to the development of new ventilation modes including neurally adjusted ventilatory assist （NAVA）. This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity （Edi） and transmit it to trigger the ventilator in synchrony with the patient’s own respiratory efforts. This permits the patient to control peak inspiratory pressure, mean airway pressure and tidal volume. Back up pressure control （PC） is provided when there is no Edi signal and no pneumatic trigger. Compared with standard conventional ventilation, NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants. NAVA is safe mode of ventilation. The majority of studies have shown no signifcant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage, pneumothorax, or necrotizing enterocolitis when compared to conventional ventilation. Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive. Most previous studies and tr
