Sustained arterial blood pressure elevation associated with pneumothoraces: early detection via continuous monitoring

The diagnosis of pneumothorax in the neonate is often heralded by such signs as deterioration of arterial blood gases, arterial hypotension, and cardiac arrest. An awareness of more subtle clinical signs of accumulating extra-alveolar gas may lead to earlier intervention and a decrease in morbidity. Fourteen episodes of pneumothorax developed in seven of 69 neonates who received ventilatory assistance (mean birth weight 1,828 +/- 295 gm), of whom six were ventilated for hyaline membrane disease and one for pneumonia. Instantaneous heart rate and arterial blood pressure (ABP) were monitored continuously in all patients. Changes in vital signs were noted at a mean of 48 minutes (range 12 to 116 minutes) prior to thoracentesis. There was an increase in systolic ABP (7 to 26 mm Hg) associated with 70% of the episodes, and an increase in heart rate and pulse pressure associated with 57% of the episodes. By 20 minutes after thoracentesis there was a rapid decrease in ABP values toward levels not significantly different from base line. A sustained increase in ABP may be an early sign of accumulating extra-alveolar gas. Continuous monitoring and graphic representation of vital signs in the ventilated neonate may suggest the diagnosis of pneumothorax before clinical decompensation occurs.