Pathophysiologically Based Ventilatory Management of Severe Bronchopulmonary Dysplasia.

Abstract

Both “new” and “old” bronchopulmonary dysplasia features overlap in preterm infants with severe bronchopulmonary dysplasia. The optimal ventilation strategy for infants with severe bronchopulmonary dysplasia has not been clarified yet. Principally, the lung is a multi-compartmental heterogeneous tissue with regionally varying compliance and resistance.Generally, 2 critical strategical errors are common while ventilating infants with established bronchopulmonary dysplasia: (i) ventilatory management as if they are still in the acute phase of respiratory distress syndrome and (ii) early extubation attempts with the aim of reducing ventilator-induced lung injury. Considering the heterogeneous character of bronchopulmonary dysplasia, although there is no unique formulation for optimal ventilation, the most physiologically appropriate ventilation mode may be the combined mode of volume-guaranteed synchronized intermittent mechanical ventilation and pressure support ventilation. With the volume-guaranteed synchronized intermittent mechanical ventilation mode, slow compartments of the lung with high resistance and low compliance can be adequately ventilated, while fast compartments having relatively normal resistance and compliance can be ventilated well with the pressure support ventilation mode. The following settings are advisable: frequency = 12-20 breaths per minute, tidal volume = 10-15 mL/min, positive end expiratory pressure = 7-12 cmH2O, and inspiratory to expiratory time ratio = 1 : 5. Higher oxygen saturations such as 92%-95% should be targeted to avoid subsequent pulmonary hypertension.In conclusion, there is no evidence-based ventilation recommendation for infants with severe bronchopulmonary dysplasia. However, given the changing pattern of the disease and the underlying pathophysiology, these infants should not be ventilated as if they were in the acute phase of respiratory distress syndrome.