Breathing pattern and efficiency of the respiratory muscles in healthy prematures and in prematures with respiratory distress syndrome.
The relationship between the compliance of the respiratory system (Crs), measured by mouth occlusion technique, and the the breathing pattern, the central inspiratory activity, and the performance of the respiratory muscles respectively, was studied in healthy prematures and in prematures presenting with the respiratory distress syndrome. With decreasing Crs, respiratory rate, instantaneous minute-ventilation, airway pressure at 0.1 s after end-expiratory occlusion (P0.1), effective inspiratory impedance, the average rate of change of the pressure generated during the inspiratory effort against closed airways, and the work of breathing increased; inspiratory and expiratory times decreased overproportionally. We conclude that the changes in lung mechanics predispose prematures with a Crs of less than 1 ml X cmH2O-1 to develop respiratory failure because they cannot perform the respiratory work demanded by intact central regulation mechanisms.
D000403:Airway Resistance; D003964:Diaphragm / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007366:Intercostal Muscles / Q000503:physiopathology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D010369:Pectoralis Muscles / Q000503:physiopathology*; D012119:Respiration; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology*; D014692:Ventilation-Perfusion Ratio; D014939:Work of Breathing