Nasal CPAP employing a jet device for creating positive pressure.

A nasal CPAP system consisting of a jet device (weight 5 g) connected with a binasal nose-piece is described. A positive airway pressure is obtained with the system applied to newborn infants provided a certain magnitude of air is brought to the jet device, and a resistance, presented by the airways, exists against the flow of air. As the system requires neither a manometer nor an excess pressure safety valve, pressures in the nasopharynx were recorded at various jet flows to illustrate the flow/pressure relationship. The CPAP can easily be etablished at definite pressures by simple adjustment of the jet flow, using this flow/pressure curve. The system appeared efficient for the treatment of apnoea, apparently due to a special attribute of the jet device. Oesophageal pressures were measured at various gas flows and at various stages of RDS, and in children with healthy lungs. The pressure appeared high with increased density of the lungs, but constant in healthy lungs despite various gas flows. Extreme pressure excursion were recorded during crying and increased muscular tone. This may explain the high frequency of pneumothorax in RDS.