Abstract 108

Background. Severe CDH is associated with lung hypoplasia, low lung volumes, low dynamic compliance (CDYN), high airway resistance(RAW) and often pulmonary hypertension and compromised gas exchange. Surgical repair is postponed until the baby is stabilized, on the grounds that removal of abdominal organs from the thoracic cavity is not beneficial in the presence of poor gas exchange. Aims. To study the effects of surgical repair on lung mechanics and gas exchange in newborn infants with severe CDH. Materials and Methods. Tidal Volume (VT ml/kg), Minute Ventilation (VE ml/min/kg), CDYN(ml/cmH2O/Kg) and RAW (cmH2O/ml/min) were measured with a BICORE CP100 (Sensor Medics) in 5 infants (BW 2020-3660 g; GA 33-42 w; postnatal age 2-25 d) with severe left CDH, 6h before and 6h after surgical repair. All babies were curarized, intubated and ventilated by IPPV with a Babylog 8000 ventilator (Dräger): the ventilator settings and the FiO2 were maintained constant troughout the period of observation. Results. VT, VE and CDYN were significantly lower and RAW significant higher than normal before surgery. After surgical repair there was a marginal improvement in lung function: average (SD) changes and p values (p) were respectively: VT + 1.08 (0.83) ml/kg (p<0.05); VE +80 (62) ml/min/kg(p<0.05); CDYN +0.16 (0.30) ml/cmH2O (p-n.s.); RAW-14(29) cmH2O/ml/min (p-n.s.). Arterial pH and blood gases did not change appreciably. Conclusions. Surgical repair of severe CDH does not seem to improve significantly lung function; prognosis is determined by the severity of respiratory insufficiency rather than the precocity of surgery.(Supported by grants code 95/02/P/387 and 96/02/P/440 of the Italian Ministry of Health).