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Objectives: High-altitude pulmonary edema (HAPE) can develop in unacclimatized persons after acute ascent to high altitude and is associated with fibrinolytic and coagulation abnormalities. The authors investigated whether fibrinolytic and coagulation abnormalities were associated with the severity of HAPE., Methods: Sixty-one patients who developed HAPE after acute ascent to altitudes above 3600 m were recruited. Twenty unacclimatized controls who acutely ascended to the same altitude and 20 acclimatized inhabitants served as controls. Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) levels were measured using chromogenic substrate assays. Plasma fibrinogen concentration was determined by the sodium sulphite fractionation method. The concentrations of fibrin/fibrinogen degradation products (FDP) and D-dimer were measured by enzyme linked immunosorbent assay., Results: The plasma concentrations of D-dimer, fibrinogen, FDP and t-PA and PAI-1 were significantly higher in patients with HAPE than controls. In addition, these abnormalities were correlated with the severity of HAPE. The plasma concentrations of D-dimer and fibrinogen recovered to normal upon recovery from HAPE while t-PA, PAI-1 and FDP levels in HAPE patients still remained significantly increased over those of unacclimatized controls., Conclusion: The development of HAPE is associated with abnormalities in the fibrinolysis and coagulation system, and these abnormalities correlate with the severity of HAPE.

High altitude illnesses pose health threats to unwary travelers after their acute ascent to high altitude locations. The incidence of high altitude illnesses among unacclimatized persons who acutely ascend to Tibet has not been previously reported. In the present study, we surveyed the incidence of high altitude illness among 3628 unacclimatized persons who had no previous high altitude experience and who traveled to Tibet by air to an altitude of 3600 m. These subjects were asked to answer questions in a written questionnaire about symptoms associated with high altitude illnesses that occurred within 2 weeks of their first arrival, their severity, and possible contributing factors. Physical examination and appropriate laboratory tests were also performed for hospitalized subjects. We found that 2063 respondents had mild acute mountain sickness with an incidence of 57.2%, and 249 (12.07%) of them were hospitalized for treatment. The incidence of high altitude pulmonary edema was 1.9%, while no case of high altitude cerebral edema was found. Additionally, there was no report of death. Psychological stresses and excessive physical exertions possibly contributed to the onset of HAPE. Acute mountain sickness is common among unacclimatized persons after their acute ascent to Tibet. The incidence of HAPE and HACE, however, is very low among them.

Objective: To assess the role of oxidative metabolism and nitric oxide synthesis for elucidating their pathophysiological mechanisms in a Tibetan patient with essential hypertension., Methods: The serum levels of total superoxide dismutase (T-SOD), malondialdehyde (MDA), total antioxidant capacity (T-AOC), nitric oxide (NO) and nitric oxide synthase (NOS) were assayed in sixty native Tibetans (thirty hypertensive patients and thirty healthy volunteers as control)., Results: The levels of T-SOD, T-AOC, NO and NOS were significantly lower in the patient group than in the control group (P < 0.01); MDA was significantly higher in the patient group than in the control group (P < 0.01). The level of MDA had a strong negative correlation with T-SOD, T-AOC, NO and NOS (r = -0.82, -0.76, -0.79, -0.73, respectively, P < 0.001 for all)., Conclusion: Tibetan patients with essential hypertension (EH) may have underlying oxidative metabolism dysfunction and depressed NO synthesis, both responsible for the hypertensive process.