title: [The respiratory center in normal subjects at 2,240 meters above sea level. The ventilatory and occlusion pressure (P 0.1) responses upon CO2 stimulation].
abstract: Altitude hypoxia imposes acute changes and long term adjustments in the ventilation of human beings. Most of the present knowledge of the respiratory center behavior at high altitude derives from the studies of ventilatory response to both hypoxia and hypercapnea. Other indexes of respiratory center output such as the occlusion pressure (P 0.1) response to a variety of stimuli are at present being evaluated. We could not find, however, studies on the P 0.1 responses to CO2 at high altitude. In this study we analyze the ventilatory and P 0.1 responses to CO2 in a group of 32 normal subjects, all of them natives and residents of Mexico city (altitude of 2,240 meters) and we compared them with those reported at sea level. The slope of both, the ventilatory and P 0.1 responses to CO2 was found to be similar to that reported at sea level; 4.52 +/- 1.29 L. min. mmHg and 0.07 +/- 0.01 cm H2O/mmHg respectively. The crossing over of such responses, however, is shifted to the left of the reported at sea level. This means higher levels of both ventilation and P 0.1, for the same level of end-tidal PCO2, at high altitude. This finding might be explained in the basis of the so-called "acclimatization to hypocapnea".
mesh_terms: D000064:Acclimatization; D000328:Adult; D000531:Altitude; D002245:Carbon Dioxide / Q000097:blood; D002555:Cerebrospinal Fluid / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000502:physiology; D010313:Partial Pressure; D012125:Respiratory Center / Q000502:physiology*; D012129:Respiratory Function Tests
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
vernacular_title: Estudio del centro respiratorio en sujetos normales a 2,240 metros sobre el nivel del mar. La respuesta ventilatoria y de la presión de oclusión (P 0.1) al estímulo del CO2.