Biomedical subjects

E D'angelo

Publications and source records attributed to E D'angelo.

3 recordsLinked to original sources

PubMed1977

Effects of uneven elastic loads on breathing pattern of anesthetized and conscious men.

In anesthetized subjects rib cage strapping (RCS) did not change tidal volume (VT) and increased ventilation (V), whereas abdomen strapping (AS) markedly decreased VT and V. Both kinds of strapping decreased expiratory duration (TE), but did not change inspiratory duration (TI) and breathing rate. RCS and AS decreased lung volume by about 200 ml and increased the elastance of the repiratory system by 12 cm H2O/1 and 9 CM H20/l, repectively. The changes produced are mainly due to mechanical factors, although reflexes also seem to be operating in some cases. In conscious subjects RCS decreased VT, TI, TE and did not change V, whereas AS did not change these parameters. The different changes in conscious and anesthetized subjects show the effects of cortical influences, which also partly explain the differen effects elicited in conscious subjects by RCS and AS. The effects produced by RCS are mainly due to the sensation of hindrance to rib cage expansion, rather than to that of rib cage squeezing, as shown by experiments of RCS without reduction of rib cage volume.

Abdomen↗

PubMed1975

Immediate response to expiratory threshold load.

In anesthetized rabbits, cats and dogs the end-inspiratory volume referred to normal FRC (deltaVe.i.) of the first breath during expiratory threshold load (ETL) was greater than control deltaVe.i. The increase of deltaVe.i. was roughly proportional to the increase of end-expiratory volume relative to normal FRC (deltaVe.e.) caused by ETL. During squeezing of the rib cage or of the abdomen or after cordotomy at T1 the phenomenon occurred nearly to the same extent. This suggests that afferent impulses from the chest wall are not essential in determining the phenomenon. The first inspiration during ETL occurred after a delay that was roughly proportional to the increase of deltaVe.e: the arterial Pco2, however, was not significantly increased at the time of the first inspiration during ETL. After bilateral vagotomy the first inspiration during ETL was no longer increased. An explantation of the increased deltaVe.i. of the first inspiration during ETL is provided on the basis of the vagal dependent tidal volume-inspiratory duration characteristic of the respiratory center.

Animals↗

PubMed1975

Stress-strain relationships during uniform and non uniform expansion of isolated lungs.

Stress-strain relationships in various directions were determined on isolated rabbit and cat lungs both during unrestrained and restrained expansion, the latter approximating the condition of cylindrical deformation. Under this condition the distortion due to the weight supported at the lung surface was also studied. Experimental data did not fit the equilibrium equations for a continuum solid, except for relatively small distortions of lung parenchyma. On the contrary, over the full range of lung distortions they fitted a model made up by a three-dimensional network of interconnected springs. While distortions produced even at relatively low lung volumes caused substantial changes of surface pressure distribution, the distorting effects of the weight were negligible under this respect. These results support the conclusion that pleural surface pressure distribution in rabbits, cats and dogs is mainly due to the lung distortion caused by the mismatching between lung and chest wall inherent shapes, while that caused by the lung weight plays only a minor role.

Animals↗