Respiratory Physiology at Altitude

Abstract

The changes in respiratory physiology that occur with increasing altitude are driven by the fall in the partial pressure of oxygen that occurs with decreasing barometric pressure. At altitude, respiratory system changes occur which impact on each step of the oxygen cascade that occurs within the body. These changes are pivotal to the process of acclimatisation to altitude. The study of human respiratory physiology at altitude has the potential to produce research that will be translational to disease states characterised by hypoxaemia.

Sudden onset hemiplegia at high altitude

“…The Valsalva manoeuvre is performed to raise right atrial pressure. The vasoconstriction of the pulmonary vasculature seen at high altitude12 would also increase right atrial pressure, increasing the likelihood of right-to-left shunting.…”

Syncope at altitude: An enigmatic case

“…Ventilatory response increases via peripheral chemoreceptors, thus lowering P a CO 2 (hypocapnia), which in turn can inhibit ventilation. Respiratory alkalosis gradually leads to renal compensation by bicarbonate diuresis . Over time, P a CO 2 and H + ions increase, stimulating central chemoreceptor‐mediated ventilatory drive.…”

“…Respiratory alkalosis gradually leads to renal compensation by bicarbonate diuresis. 13 Over time, P a CO 2 and H þ ions increase, stimulating central chemoreceptor-mediated ventilatory drive. Hypobaric hypoxia also stimulates vasodilatation and consequent sympathetic reflex over-activity and this increases heart rate, maintains blood pressure, and adequate oxygen delivery.…”

Pulmonary Function Tests Vary in Different Cities of Baluchistan, Pakistan

“…Researchers have linked BMI to changes in lung function relation between BMI and pulmonary function has been previously examined and BMI has been reported to be negatively associated with values for dynamic lung volumes including forced vital capacity (FVC) and forced expiratory volume in first second (FEV1) 8 .The core features vary population to population and habitat to habitat even in the same country reference values differs, town specific reference values play vital role in studying various respiratory functions, defects leads to several maladies and spirometric variations which reveals the pulmonary function variations 20 . Lung function is known to vary with different ethnicity, and it is therefore important to set up normative values applicable to the ethnic group of the local population and therefore lung function values for a given ethnic group can be change over time .We conclude that FVC, FEV1, PEFR, and FEV1/FVC have significant differences in mean, the means of Baluchistan city were less than a per standard Chamanern mean values, it also gives significant differences within Citys of Baluchistan city as spirometric values exclusively depends upon body shape, chest size, BMI, Age, environment, life style, anatomical differences, altitude and lung development.…”