When a subject is totally immersed in water while holding his breath, a loss of buoyancy occurs.This phenomenon can be demonstrated by resting the subject on 1 pan of a balance, the loss of buoyancy being reflected as a gain in weight on the balance. This gain in weight (or loss of buoyancy) was first observed by us while determining body density by an underwater weighing method (1). This gain ...

Three submariners were confined in a chamber for 284 hours in a heliumoxygen-nitrogen environment at 7 atmospheres pressure. Electrodermal conductance (EDC) levels, changes and recoverability prior to and following hyperventilation and breathholding were obtained before, three times during, and once at the termination of the pressurization phase of the experiment. In addition, breathholding tim...

Single-breath transfer factor obtained using a multibreath estimate of alveolar volume (TI) was measured before and after salbutamol in twenty patients with reversible airflow limitation. The effective breathholding time was calculated by four methods due respectively to Ogilvie and colleagues as modified by the American Thoracic Society (ATS), ATS Epidemiological Standardization Project (ESP),...

Background Cine DENSE MRI is an established myocardial strain imaging technique with high accuracy and rapid data analysis. Current cine DENSE protocols utilize breathholding (BH); however, this practice limits the use of this technique to patients with good BH capabilities, excluding many pediatric and some heart failure patients. We propose a free-breathing (FB) framework for cine DENSE that ...

The nature of the pulmonary capillary blood flow is fundamental for the understanding both of pulmonary hemodynamics and of respiratory gas exchange. Direct examinations of the surface of the lung in the cat, rabbit, dog and rat (1-5) have indicated that pulmonary capillary blood flow is basically non-pulsatile. On the other hand, experimental studies by Lee and DuBois (6), using the body pleth...

The nature of the pulmonary capillary blood flow is fundamental for the understanding both of pulmonary hemodynamics and of respiratory gas exchange. Direct examinations of the surface of the lung in the cat, rabbit, dog and rat (1-5) have indicated that pulmonary capillary blood flow is basically non-pulsatile. On the other hand, experimental studies by Lee and DuBois (6), using the body pleth...