High Altitude Pulmonary Hypertension

The effects of hypoxia on the human organism has been considered doubly fascinating by the scientific community. The knowledge of the discrete mechanisms allowing the acclimatization both at genetic level or through the cell mediators production in addition to the macroscopic responses of the cardio-circulatory and ventilatory systems to a hypoxic environment has been progressively developed since the last century; moreover granting a safer stay in hypoxic conditions not only for the residents but also for the different cathegories of workers, sportsmen and tourists has been considered a worthy aim of the medical activity. The effects of hypoxia were simulated in laboratory by means of an induced low pressure environment (normobaric hypoxia) or tested on the subjects at different levels of altitude (hypobaric hypoxia). Far from describing all the physiological and pathological responses of the organism, in this review, the authors expose the state of the art in the knowledge of the responsiveness of the pulmonary circle to the acute or chronic hypoxic condition, its possible progression to the pulmonary arterial hypertension, the latter being more appropriately named High-Altitude Pulmonary Hypertension. The currently available therapeutic options in the treatment of High-Altitude Pulmonary Hypertension are also reviewed. Keywords: Pulmonary hypertension, hypoxia, high altitude, flight, arterial blood, hemoglobin.