OBJECTIVEThe authors compared the protective ventilation strategies with the assistance of pulmonary mechanic measurements (PM) to the conventional ventilation practice in order to investigate the incidence of VALI, explore the best ventilator settings in RDS and the clinical effects of hypercapnia in neonates.

METHODSOne hundred and ten newborn infants, diagnosed as respiratory distress syndrome of neonatal and needed ventilator support, were recruited from the intensive care unit from 1994 to 2001. Infants with RDS were divided into non-pulmonary mechanics measurement (NPM) group and pulmonary mechanics measurement (PM) group. The ventilator settings, artery blood gas analysis, ventilator-associated lung injury and other clinical data were analyzed and compared.

RESULTSIn the PM group, expiratory tidal volume of (7.70 +/- 1.05) ml/kg, C(20)/C of (1.98 +/- 0.92) and time constant of (0.09 +/- 0.03) sec were measured. Ventilator setting in PM group [PIP of (26.7 +/- 1.7) cmH(2)O, MAP of (11.9 +/- 2.0) cmH(2)O, Ti of (0.45 +/- 0.10) sec] were significantly less than those in NPM group [PIP of (30.5 +/- 3.4) cmH(2)O, MAP of (14.9 +/- 3.4) cmH(2)O, Ti of (0.75 +/- 0.10) sec P < 0.001, respectively]. No differences were noted in demographic data between the two groups regarding to the pH (7.30 +/- 0.04 vs 7.31 +/- 0.10), PaO(2) [(59 +/- 16) vs (57 +/- 17) mmHg], heart rate [(145 +/- 6) vs (144 +/- 8) bpm] and blood pressure [(39.0 +/- 3.6) vs (40.0 +/- 4.6) mmHg], except for PaCO(2) in PM group which was significantly higher than that in NPM group [(48 +/- 6) vs (40 +/- 10) mmHg, P < 0.001]. OI in PM group was significantly less than that in NPM group (14 +/- 8 vs 19 +/- 13, P < 0.05). Incidence of ventilator-associated lung injury in PM group was significantly lower than that in NPM group (13% vs 32%, P < 0.05). No differences were noted in demographic data between the two groups regarding to the length of ventilator support [(4.2 +/- 1.7) vs (3.9 +/- 1.8) day], length of supplemental oxygen requirements [(13 +/- 7) vs (11 +/- 7) day], length of hospitalization [(22 +/- 11) vs (19 +/- 14) day], mortality (8% vs 14%), incidence of PDA (33 vs 36%) and IVH (40% vs 42%).

CONCLUSIONSThe assistance use of pulmonary mechanics measurement can guide the ventilator adjustment and decrease the ventilator-associated lung injury in neonatal RDS. The low PIP, low tidal volume, shorter inspiratory time and adequate PEEP strategies in the treatment of RDS showed no significant effects on the oxygenation in neonates. The mild permissive hypercarbia in newborn did not increase the incidence of IVH.