Biomedical subjects

A de la Rocha

Publications and source records attributed to A de la Rocha.

3 recordsLinked to original sources

PubMed1983

Respiratory function after paralysis of the right hemidiaphragm.

We studied a 45-yr-old man with normal lung function before and 7 wk after right phrenic nerve crush. Total lung capacity, functional residual capacity, and forced vital capacity decreased with residual volume remaining unchanged. Static compliance was also unchanged. Ventilatory response to CO2 (delta Ve/delta PaCO2) was preserved, but P0.1 response to CO2 (delta P0.1/delta PaCO2) increased. Analysis of raw mouth pressure suggested that these responses were the result of a new rapid pattern of inspiratory pressure development. Regional washout was slowed on the side with paralysis, but the normal apex-to-base gradient of regional volumes was preserved. Inhaled 133Xe boluses were distributed away from the side of paralysis, and bolus distribution changed relatively little with increased flow. These results suggested that in compensation for paralysis of a hemidiaphragm, a new pattern of inspiratory muscle recruitment developed, involving more rapid contraction of the remaining muscles of inspiration.

Forced Expiratory Volume↗

PubMed1983

Ventilatory control after pulmonary resection.

Because pulmonary resection decreases pulmonary compliance, the effects of resection on ventilation might be similar to the known effects of elastic loading. We evaluated the breathing pattern and ventilatory drive in 12 patients before and after pulmonary resection with mean tissue loss of 4 segments. During resting ventilation, the only significant change after resection was a decrease in inspiratory time (Tl). At a higher level of minute ventilation (VE), induced by CO2 rebreathing, significant changes included increased respiratory frequency, decreased tidal volume and Tl, and increased occlusion pressure (P0.1). Both ventilation and occlusion pressure responses to CO2 (delta VE/delta PACO2, delta P0.1/delta PACO2) were unchanged after resection. We conclude that increased ventilation induced by CO2 rebreathing unmasks a breathing pattern after pulmonary resection which is similar to that seen with breathing against an external elastic load.

Female↗

PubMed1975

Surgical aspects of regional myocardial blood flow and myocardial pressure.

The surgical technique of cardiopulmonary bypass with either an empty beating or an empty fibrillating ventricle produces marked changes in the regional blood flow and oxygen demand of the left ventricle. This paper describes the changes which occurred in the regional perfusion of both the normal and the hypertrophied left ventricle during these conditions and relates them to the known changes in oxygen demand. It also correlates the changes in flow with the measurable changes in myocardial tissue pressure-systolic when the heart is beating and continuous when fibrillating. The various types of filbrillation had identical effects on both regional tissue pressure and regional flow. The subendocardial blood supply was adequate or more than adequate under each of these conditions so long as the coronary perfusion pressure was maintained at an adequate level. A low perfusion pressure during ventricular fibrillation of any type led to a marked reduction in flow to the subendocardial portion of the left ventricle: The presence of ventricular hypertrophy accentuated this danger.

Animals↗