Objective To evaluate the value of pre-ascent 6-minute walking test performed at a high altitude in predicting the incidence of acute mountain sickness(AMS)induced by rapid ascent to a very high altitude.Methods After baseline information was collected,participants completed the 6-minute walking test at a high altitude of 2 900 m.Then,they rapidly ascended to a very high altitude of 5 000 m.The Lake Louise score was recorded to assess AMS.Results The AMS group showed a shorter pre-ascent 6-minute walking distance(6MWD)at the high altitude than the non-AMS group[480.00(450.00,521.75)m vs.546.00(516.50,568.50)m,P=0.006].No difference was observed regarding the pre-ascent heart rate or peripheral oxygen saturation(both P>0.05).The pre-ascent 6MWD at the high altitude was negatively correlated with the Lake Louise score assessed after rapid ascent to the very high altitude(r=-0.497,P=0.012).Logistic regression analysis confirmed that the pre-ascent 6MWD at the high altitude was associated with the risk of AMS induced by rapid ascent to the very high altitude(OR=0.971,95% CI=0.947-0.996,P=0.022).The results indicated that the pre-ascent 6MWD demonstrated ideal prediction performance(area under receiver operating characteristic curve=0.846,P=0.006).Conclusion The pre-ascent 6MWD recorded at the high altitude is a convenient and reliable predictor of the AMS induced by rapid ascent to the very high altitude.
Humans ; Altitude Sickness/diagnosis* ; Male ; Adult ; Female ; Young Adult ; Middle Aged ; Acute Disease ; Walk Test ; Walking ; Altitude ; Exercise Test

This study was performed to evaluate whether increasing hemoglobin before ascent by prophylactic erythropoietin injections prevents acute mountain sickness (AMS). This open-label, randomized, controlled trial involved 39 healthy volunteers with hemoglobin < or =15.5 g/dL who were divided randomly into erythropoietin (n=20) and control (n=19) groups. Epoetin alpha 10,000 IU injections were given weekly for four consecutive weeks. On day 1, and 7 days after the last injection (day 29), oxygen saturation (SaO2), and hemoglobin were measured. The subjects departed Seoul on day 30 and arrived at Annapurna base camp (ABC, 4,130 m) on day 34. AMS was diagnosed when headache and Lake Louise score (LLS) of > or =3 were present. Immediate descent criteria followed US Army recommendations. Two groups differ in hemoglobin levels on day 29 (15.4+/-1.1 vs 14.2+/-1.0 g/dL, P=0.001). At ABC, erythropoietin group had a significantly lower mean LLS, AMS incidence, and number of subjects who met immediate descent criteria. Multiple logistic regression analysis showed that SaO2<87% and control group, but not hemoglobin<15.0 g/dL, independently predicted satisfaction of immediate descent criteria. Erythropoietin-related adverse effects were not observed. In conclusion, erythropoietin may be an effective prophylaxis for AMS.(Clinical Trial Registry Number; NCT 01665781).
Acute Disease ; Adult ; Altitude Sickness/diagnosis/epidemiology/*prevention & control ; Blood Pressure/physiology ; Drug Administration Schedule ; Erythropoietin/*therapeutic use ; Female ; Headache/physiopathology ; Hemoglobins/analysis ; Humans ; Incidence ; Logistic Models ; Male ; Middle Aged ; Odds Ratio ; Oxygen/blood ; Questionnaires ; Recombinant Proteins/therapeutic use

Sudden ascent to high altitudes beyond 2,438 m can cause life-threatening complications such as acute mountain sickness and high altitude cerebral and pulmonary oedema. We present a case of pituitary apoplexy in a young man who ascended to high altitude gradually, after proper acclimatisation. He developed headache, nausea, vomiting and persistent hypotension. Magnetic resonance imaging revealed an enlarged pituitary gland with haemorrhage. His hormonal estimation showed acute adrenal insufficiency due to corticotropin deficiency. The patient responded well to conservative medical management with hormonal replacement therapy. This is most likely the first reported case of high altitude-induced pituitary apoplexy in the literature.
Acclimatization ; Adrenal Insufficiency ; complications ; Adrenocorticotropic Hormone ; deficiency ; Adult ; Altitude ; Altitude Sickness ; complications ; Brain ; pathology ; Hormone Replacement Therapy ; methods ; Humans ; Hypotension ; physiopathology ; Intracranial Hemorrhages ; physiopathology ; Magnetic Resonance Imaging ; methods ; Male ; Pituitary Apoplexy ; diagnosis ; etiology ; Pituitary Gland ; physiopathology

Altitude Sickness ; diagnosis ; Humans ; Occupational Diseases ; diagnosis ; Reference Standards

Critical care medicine (CCM) is one of the challenging issue in clinical practice. The key issues of CCM include acute lung injury, acute respiratory distress syndrome, and multiple organ dysfunction syndrome (MODS), generally termed as systemic inflammatory response syndrome (SIRS). When SIRS occurs at high altitude areas (H-SIRS), it will need be distinguished with an idiopathic acute high altitude sickness (generally termed as acute high altitude reaction syndrome), that make the differential diagnosis and treatment of H-SIRS even more difficult. It has became a high priority to properly address the relevant issues in this field: construction of disciplines; identification of speciality scopes; standardization of the diagnosis and treatment of CCM; and decreasing of the mortality of MODS at high altitude.
Acute Lung Injury ; diagnosis ; prevention & control ; therapy ; Altitude ; Altitude Sickness ; diagnosis ; Diagnosis, Differential ; Humans ; Multiple Organ Failure ; diagnosis ; prevention & control ; therapy ; Respiratory Distress Syndrome, Adult ; diagnosis ; prevention & control ; therapy ; Systemic Inflammatory Response Syndrome ; diagnosis ; prevention & control ; therapy

AIMTo explore whether hypoxic response and breath holding at sea level could predict acute mountain sickness (AMS).

METHODS113 men aged (19 +/- 1) years took part in this study. Blood oxygen saturation (SaO2), heart rate and blood pressure were measured during the course of breathing 10% O2 for 10 minutes and breath holding. Two days later after reaching Lasa (3 658 m altitude) by air, the symptomatic scores of AMS were evaluated. Then the relations between them were analyzed.

RESULTSThe SaO2 reduced progressively and the heart rate speeded up, while the blood pressure represented increase at first and then decrease within 10 min during the short-term hypoxia. The heart rate was lower during short-term hypoxia in subjects who developed AMS than in subjects doing well. But significant reverse correlation existed only between AMS scores and heart rate at 7th min after hypoxic breathing (r = -0.176).

CONCLUSIONLimited information can be gained on AMS score by assessing physiological responses to short-term hypoxia and breath holding at sea level.

Acute Disease ; Adolescent ; Altitude Sickness ; diagnosis ; physiopathology ; Breath Holding ; Humans ; Hypoxia ; diagnosis ; physiopathology ; Inhalation ; Male ; Pulmonary Gas Exchange ; Young Adult