THE USE OF CONSTANT NEGATIVE DISTENDING PRESSURE (CNDP) IN THE TREATMENT OF PULMONARY INTERSTITIAL EMPHYSEMA (PIE)

Abstract

Pulmonary interstitial emphysema (PIE) Is an occasional complication in infants with severe hyaline membrane disease on assisted ventilation (IPPB), most commonly in infants weighing <1500 gm. It is frequently followed by pneumothorax, subcutaneous emphysema and bronchopulmonary dysplasia. Treatment has consisted of differential intubation (unilateral), open thoracotomy with splaying of the lung, and chest tubes to rupture larger bullae.Five newborns weighing 1500 gm or less with bilateral PIE on x-ray were treated with constant negative distending pressure (CNDP). Three had significant bilateral PIE with subsequent pneumothoraces and elevation of pCO2 to 60-100 mmHg. The infants were placed in a negative pressure chamber with CNDP -3 to -6 cm H2O. IPPB was continued but without positive end expiratory pressure (PEEP). As the infant's clinical condition improved, the peak inspiratory pressure (PIP) was decreased. Over the next 12 to 24 hours the PIP were lowered significantly. There was no progression of PIE, and a gradual resolution over the next few days. The infants' pCO2 gradually dropped from the 60's to normal range of 40-50. We conclude that where mechanical ventilation is necessary with PIE, CNDP should replace PEEP which allows lower PIP to ventilate the infant adequately and prevents further complicatIons.