STATIC COMPLIANCE IN INFANTS WITH HMD. EFFECTS OF DIFFERENT LEVELS OF PEEP

Abstract

The measurement of lung compliance is useful in establishing the optimal PEEP in the treatment of adult RDS. This study was conducted to assess the value of this determination in infants with HMD. Six newborns (B.W. 1340 gm, Gest. age 31 weeks) who required mechanical ventilation because of severe HMD were studied. Airway pressure, tidal volume and esophageal pressure were recorded at different levels of PEEP and peak pressure (PIP) while the infant's respiration was controlled using a prolonged inspiration, so that tidal volume and airway pressure reached a plateau. The values of static compliance (ml/cm H2O) were: Lung compliance decreased as PEEP or PIP were increased, suggesting that no significant alveolar recruitment occurred. The pressure/volume curve did not show a linear part, but became progressively flatter as the PIP increased. The use of PEEP moved the tidal volume into this flatter part of the curve. The only exception to this was the decrease in CL seen at O PEEP and PIP of 10 cm H2O or less, indicating alveolar collapse. In conclusion, increasing PEEP produces a progressive decrease in CL and therefore this measurement is of no value in determining the optimal PEEP in infants with HMD.