Evaluation of methods of assisted ventilation in hyaline membrane disease

Two methods of providing assisted ventilation were compared in infants severely ill with hyaline membrane disease (HMD). 10 infants were assigned to each group. One group received ventilation with a volume-cycled respirator, and the other was ventilated using a pressure-limited ventilator and reversed I:E ratio. Both groups were well matched for severity of illness in terms of pH and blood gases. pH and PO2 were quickly corrected by both ventilators. However, the pressure-cycled ventilator group had higher survival and lower complication rates. PAO2 after one hour was substantially improved at the same FIO2 in the pressure-limited group and after 8 hours the FIO2 required to maintain a PaO2 of 50--70 mmHg (6.6--9.3 kPa) was significantly decreased compared with the volume-cycled group. No effects on blood pressure were detected in either group. The study shows that the pressure-limited method is significantly better.