The effect of stimulus frequency on the in vivo pressure generating capacity of the human diaphragm is unknown at lung volumes other than functional residual capacity. The transdiaphragmatic pressure (Pdi) produced by a pair of phrenic nerve stimuli may be viewed as the sum of the Pdi elicited by the first (T1 Pdi) and second (T2 Pdi) stimuli. We used bilateral anterior supramaximal magnetic ph...

1. The functional residual air (defined as the lung volume at the end of normal expiration) has been determined in a series of normal individuals and in ten patients with lobar pneumonia at different stages of the disease. 2. The rate, depth, and minute volume of respirations were measured in the same individuals by a graphic method. 3. When appreciable cyanosis was present the oxygen content a...

Gravity-dependent changes of regional lung function were studied during normogravity, hypergravity, and microgravity induced by parabolic flights. Seven healthy subjects were followed in the right lateral and supine postures during tidal breathing, forced vital capacity, and slow expiratory vital capacity maneuvers. Regional 1) lung ventilation, 2) lung volumes, and 3) lung emptying behavior we...

Pulmonary function tests have rarely been assessed in preschool children with cystic fibrosis (CF). The objective of this multicenter study was to compare pulmonary function in 39 preschool children with CF (height, 90-130 cm; 16 homozygous Delta F508) and in 79 healthy control children. Functional residual capacity (helium dilution technique) and expiratory interrupter resistance (Rint(exp)) (...

Airway conductance is known to increase with an increase in the lung volume at which it is measured, owing to a change in transpulmonary pressure and lung tissue tension. We investigated the effect of surgical resection of lung tissue on functional residual capacity and airway conductance in patients with localized lung disease (i.e., carcinoma or tuberculosis) and in patients with lung cysts o...

It is still not known whether persistent increases in functional residual capacity (FRC) and residual volume (RV) after lung transplantation are due to preexisting hyperinflation. Therefore, the aim of this study was to determine the effects of chronic lung hyperinflation on static lung volumes after heart/lung (HLT) and bilateral lung transplantation (BLT). Static lung volumes were measured in...

The purpose of this study was to register breathing patterns, in healthy subjects, during breathing with a positive expiratory pressure. Integrated electromyographic (IEMG) activity of the following muscles was assessed: scalene muscle, parasternal muscle and abdominal muscles, using surface electrodes. Inspiration time, expiration time, total breathing cycle time, tidal volume and breathing fr...