Objective To examine if the variations at sea level would be able to predict subsequent susceptibility to acute altitude sickness in subjects upon a rapid ascent to high altitude. Methods One hundred and six Han nationality male individuals were recruited to this research. Dynamic electrocardiogram, treadmill exercise test, echocardiography, routine blood examination and biochemical analysis were performed when subjects at sea level and entering the plateau respectively. Then multiple regression analysis was performed to construct a multiple linear regression equation using the Lake Louise Score as dependent variable to predict the risk factors at sea level related to acute mountain sickness (AMS). Results Approximately 49.05% of the individuals developed AMS. The tricuspid annular plane systolic excursion (22.0±2.66 vs. 23.2±3.19 mm, t=1.998, P=0.048) was significantly lower in the AMS group at sea level, while count of eosinophil [(0.264±0.393)×10⁹/L vs. (0.126±0.084)×10⁹/L, t=-2.040, P=0.045], percentage of differences exceeding 50 ms between adjacent normal number of intervals (PNN50, 9.66%±5.40% vs. 6.98%±5.66%, t=-2.229, P=0.028) and heart rate variability triangle index (57.1±16.1 vs. 50.6±12.7, t=-2.271, P=0.025) were significantly higher. After acute exposure to high altitude, C-reactive protein (0.098±0.103 vs. 0.062±0.045 g/L, t=-2.132, P=0.037), aspartate aminotransferase (19.7±6.72 vs. 17.3±3.95 U/L, t=-2.231, P=0.028) and creatinine (85.1±12.9 vs. 77.7±11.2 mmol/L, t=-3.162, P=0.002) were significantly higher in the AMS group, while alkaline phosphatase (71.7±18.2 vs. 80.6±20.2 U/L, t=2.389, P=0.019), standard deviation of normal-to-normal RR intervals (126.5±35.9 vs. 143.3±36.4 ms, t=2.320, P=0.022), ejection time (276.9±50.8 vs. 313.8±48.9 ms, t=3.641, P=0.001) and heart rate variability triangle index (37.1±12.9 vs. 41.9±11.1, t=2.020, P=0.047) were significantly lower. Using the Lake Louise Score as the dependent variable, prediction equation were established to estimate AMS: Lake Louise Score=3.783+0.281×eosinophil-0.219×alkaline phosphatase+0.032×PNN50. Conclusions We elucidated the differences of physiological variables as well as noninvasive cardiovascular indicators for subjects after high altitude exposure compared with those at sea level. We also created an acute high altitude reaction early warning equation based on the physiological variables and noninvasive cardiovascular indicators at sea level.
Acute Disease ; Adolescent ; Adult ; Alkaline Phosphatase/blood* ; Altitude ; Altitude Sickness/physiopathology* ; Aspartate Aminotransferases/blood* ; Blood Pressure/physiology* ; C-Reactive Protein/analysis* ; Creatinine/blood* ; Electrocardiography/methods* ; Exercise Test/methods* ; Heart Rate/physiology* ; Humans ; Leukocyte Count ; Male ; Risk Factors ; Young Adult

Objective To identify the physiological variables associated with the development of acute mountain sickness (AMS). Methods Eighty four young Chinese men residing at low altitude were taken to an altitude of 4000 m within 40 hours. At sea level and at high altitude, we measured the heart rate, blood pressure, and peripheral oxygen saturation (SpO₂) respectively. We also collect blood samples from each participants before and after the altitude elevation. The blood routine and biochemical examinations were performed for all blood samples. The revised Lake Louise Criteria was adopted to diagnose AMS after the subjects arrived at the target high altitude. The association between the presence of AMS and subjects' physiological variables were analysed statistically. Results Of 84 participants, 34 (40.5%) developed AMS. Compared with non AMS group, in the AMS group, the percentage of neutrophils was significantly higher (64.5%±11.2% vs. 58.1%±8.8%, P =0.014), while the level of SpO₂ was significantly lower (79.4%±5.4% vs. 82.7%±5.6, P=0.008). Binary logistic regression analyses emphasized the association of neutrophils (OR: 1.06, 95% CI: 1.01-1.12, P=0.034) and SpO₂ level (OR: 0.87, 95% CI : 0.79-0.95, P=0.004) with the development of AMS. Conclusion The ability to sustain SpO₂ after altitude elevation and the increase of neutrophils were associated with the development of AMS in young males.
Acute Disease ; Adolescent ; Adult ; Altitude Sickness/physiopathology* ; Blood Pressure/physiology* ; Heart Rate/physiology* ; Humans ; Logistic Models ; Male ; Oxygen ; Young Adult

OBJECTIVETo study the selective dilatation effects of iptakalim (Ipt) on basilar and pulmonary arterioles, and endothelial cell function of these arterioles in hypoxic rats.

METHODSSD male rats were divided into 2 groups:control and hypoxic group fed in normobaric hypoxic environment (O2 7.8%, 8 h). Arteriole rings about (204 + 5) pm were isolated and the tension of hypoxic arterioles pre-contracted by 6 nmol/L endothelin-1 (ET-1) was observed with wire myograph system model (DMT 610 m). The relaxing response of hypoxic arterioles induced by different concentration of Ipt were detected and endothelial activity was also tested by acetylcholine.

RESULTS10(5) mol/L acetylcholine (ACh)-mediated vasodilatation of basilar and pulmonary arterioles was greatly reduced in the hypoxic group than those in control group (P < 0.05). Compared with normal group, a novel ATP-sensitive potassium channel opener Ipt at the concentration ranging from 10(-11) mol/L to 10(3) mol/L, caused stronger dose dependent vasodilatation on hypoxic pulmonary arterioles, and there was no significant difference between control and hypoxic basilar arterioles.

CONCLUSIONThe endothelial function of basilar and pulmonary arterioles was damaged under hypoxic state, and Ipt selectively increased dilatation effects on hypoxic pulmonary arterioles, but not on hypoxic basilar arterioles which could improve high altitude pulmonary edema pathological state and be the novel drug in the treatment of pulmonary hypertension.

Acetylcholine ; pharmacology ; Altitude ; Altitude Sickness ; physiopathology ; Animals ; Arterioles ; drug effects ; Dilatation ; Endothelin-1 ; pharmacology ; Hypoxia ; KATP Channels ; drug effects ; Male ; Propylamines ; pharmacology ; Rats ; Vasodilation ; Vasodilator Agents ; pharmacology

OBJECTIVETo investigate the changes of the cardiac hemodynamics after acute high altitude exposure in healthy young males and the relationship with acute mountain sickness(AMS).

METHODSLeft ventricular function and oxyhemoglobin saturation (SaO2), heart rate (HR), blood pressure (BP) were measured in 218 healthy young males before and after high altitude exposure within 24 h respectively. According to the lake louise score criteria, the subjects were divided into two groups: acute mountain sickness group (AMS group) and non acute mountain sickness group (non-AMS group).

RESULTSHR, diastolic blood pressure (DBP), mean arterial pressure (MAP), left ventricular ejection fraction (LVEF), stroke volume (SV), stroke index (SI) cardiac output (CO), cardiac index (CI) were significantly increased upon acute high altitude exposure (P < 0.05). Whereas SaO2 and end-systolic volume (ESV) were significantly decreased (P < 0.05). In addition, HR, systolic blood pressure (SBP) and MAP in AMS group were significantly higher than those in non-AMS group (P < 0.05). But stroke index (SI) and end-diastolic volume (EDV) in AMS group were significantly lower than those in non-AMS group (P < 0.05).

CONCLUSIONCardiac function in healthy young males upon acute high altitude exposure was enhanced. EDV, HR and SI might become the indexes of predicting the acute mountain sickness in the future.

Acute Disease ; Adult ; Altitude ; Altitude Sickness ; physiopathology ; Humans ; Male ; Ventricular Function, Left ; physiology

OBJECTIVETo analysis deacclimatization symptom scores of 159 youth from Karakoram and Tibet Ali area, and provide the basis for the development of relevant prevention and control measures.

METHODSUsing the method of epidemiological symptoms questionnaire, 18 symptoms of 190 youth who returned to the plain area from the different plateau were investigated. The symptom scores of different altitude, age, the time of staying, different units, continuous or intermittent stage and education were surveyed.

RESULTSDeacclimatization symptom scores among 5,000 meter groups were significantly higher than those of 4,300 meter and 3,700 meter group (P < 0.05, P < 0.01). There was no significant difference between the 4,300 meter group and the 3,700 meter group (P > 0.05). There were significant differences among the stayed personnel (different age, position, unit, education, time, continuous or intermittent) (P < 0.01). There was significant difference between the continuous defended the group and intermittent group (P < 0.01).

CONCLUSIONDeacclimatization symptom scores were related to the plateau exposure time, altitude, workload, plateau continued exposure. The older, the longer exposure, the higher altitude, the greater workload at plateau were showed higher deacclimatization symptom score.

Acclimatization ; Altitude ; Altitude Sickness ; physiopathology ; Humans ; Surveys and Questionnaires ; Tibet

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

OBJECTIVETo assess the relationship of high altitude de-adaptation response (HADAR) with acute high altitude response (AHAR) and cardiac function.

METHODSNinety-six military personnel of rapid entering into high altitude (3 700 to 4 800 m) with strong physical work were analyzed, all subjects were male, aged 18 - 35 years. According to the symptomatic scores of AHAR were divided into 3 groups: sever AHAR (group A, 24), mild to moderate AHAR (group B, 47) and non-AHAR (group C, 25) at high altitude. According to the symptomatic scores of HADAR were divided into 3 groups: severe HADAR (group E, 19), mild to moderate HADAR (group F, 40) and non-HADAR (group G, 37) after return to lower altitude (1 500 m). Mean pulmonary arterial pressure (mPAP), right ventricular internal dimension (RVID), outflow tract of right ventricle (RVOT), left ventricular internal dimension (LVID), left ventricular ejection fraction (LVEF), cardiac muscle work index (Tei index), creatine kinase isoenzymes-MB (CK-MB), lactic dehydrogenase isoenzyme-1 (LDH-1) were measured at high altitude stayed 50 days and after return to lower altitude 12 h, 15 d, and 30 d. Fifty healthy volunteers (group D) at 1 500 m altitude served as control.

RESULTSLevel of mPAP, RVID, RVOT, RVID/LVID ratio, Tei index, CK-MB,and LDH-1 were higher, and LVEF was lower in group A than those in group B, C and D, there were significant differences between group B and C, C and D (all P < 0.01). AHAR scores were positively correlated with HADAR scores (r = 0.863, P < 0.01). Twelve hours after return to lower altitude, level of mPAP, RVID, RVOT, RVI/LVID ratio, Tei index, CK-MB, and LDH-1 were higher, and LVEF was lower in group E than those in group F, G and D, there were significant differences between group F and G, G and D (all P < 0.01). Fifteen days after return to lower altitude, level of mPAP, RVID, RVOT, RVID/LVID ratio were higher in group E than those in group F, G, and D, there were significant differences between group F and G, and D (P < 0.01 or P < 0.05), there were no significant differences between group G and D (all P > 0.05), LVEF, Tei index, CK-MB, LDH-1 showed no significant differences among groups (all P > 0.05). Thirty days after return to lower altitude, these parameters in group E, F, and G showed no significantly differences compared with those of group D (all P > 0.05).

CONCLUSIONThe severity of HADAR is associated with severity of AHAR and cardiac injury, the more serious of AHAR and cardiac injury at high altitude, the more serious of HADAR and cardiac injury after return to lower altitude, the more long of restore of right cardiac morphologic injury.

Adaptation, Physiological ; Adolescent ; Adult ; Altitude ; Altitude Sickness ; metabolism ; physiopathology ; Case-Control Studies ; Heart ; physiopathology ; Heart Function Tests ; Humans ; Male ; Myocardium ; enzymology ; Young Adult

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

OBJECTIVETo construct an apparatus for the oxygen uptake measurement of rats exposed to hypobaric hypoxia at different simulated altitude.

METHODSThe capacity of this apparatus was about 0.01 m3. It included animal experimental cabin, reference cabin, altimeter, altitude vertical velocity indicator, pressure difference inductor and oxygen compensator, low scale manometer, soda lime and calcium chloride, small fan, thermometer, circulating water system and vacuum pump. The oxygen uptake of the rats at 6 000 m, 4 000 m and 1 000 m simulated altitude was measured using this apparatus.

RESULTSThe oxygen uptake of the rats at 50 m, 4 000 m and 6 000 m simulated altitude was (24.4 +/- 2.1), (10.8 +/- 2.0) and (8.8 +/- 1.6) ml O2/(kg x min) respectively (average +/- s, n = 10). The oxygen uptake decreased as altitude increased.

CONCLUSIONThis apparatus can be used to measure the oxygen uptake of the rats at different simulated altitude.

Altitude ; Altitude Sickness ; physiopathology ; Animals ; Computer Simulation ; Equipment and Supplies ; Hypoxia ; physiopathology ; Male ; Oxygen ; metabolism ; Oxygen Consumption ; physiology ; Rats ; Rats, Sprague-Dawley

The aim of this study was to investigate the effect of integripetal rhodiola herb on pulmonary arterial remodeling and expression of vascular endothelial growth factor (VEGF) in high altitude pulmonary hypertension in rats. Fifty healthy male Wistar rats were divided into five groups randomly: Plain control group (LC group), 10-day plateau group (H(10) group), 30-day plateau group (H(30) group), 10-day rhodiola-treated plateau group (R(10) group), and 30-day rhodiola-treated plateau group (R(30) group). Each group included 10 rats. The rats in LC group were kept in Chengdu (500 meters above sea level), and rats in H and R groups were kept in Lhasa (3 700 meters above sea level). The rats in R group were daily treated with integripetal rhodiola herb extract (24%, 10 mL/kg) intragastrically for 10 d or 30 d, while rats in LC and H groups were treated with the same volume of saline. Mean pulmonary arterial pressure (mPAP) was detected via a catheter in the pulmonary artery by pressure waveform monitoring. The ratio value of right ventricle weight to left ventricle plus septum weight [RV/(LV + S)] was measured. The microstructure of pulmonary arterioles was examined by electron microscopy. The expression of VEGF in the lung was investigated using immunohistochemistry. The results showed that mPAP and [RV/(LV + S)] in H(10) group and H(30) group were higher than those in LC group (P < 0.05); but there was no significant difference between H(10) group and R(10) group (P < 0.05); and mPAP and [RV/(LV + S)] in H(30) group were lower than those in H(30) group (P < 0.05). Electron microscopy showed that compared to LC group, arteriolar endothelial cells were arranged in a columnar or palisading form, protruding into the lumen, accompanied with luminal stenosis, irregular internal elastic membrane, and proliferation of vascular smooth muscle cells in H groups, which was more obvious in H(30) group than in H(10) group; while these pathological changes were attenuated in the R groups compared to H groups. The levels of VEGF protein in H groups were also higher than those in LC group (P < 0.05); while the expression of VEGF in R(30) group was lower than that in H(30) group. In summary, the results show that the integripetal rhodiola herb can attenuate high altitude-induced pulmonary arterial remodeling in rats, and the inhibition of VEGF protein expression by rhodiola may be one of the mechanisms.
Altitude ; Altitude Sickness ; prevention & control ; Animals ; Arterioles ; metabolism ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Hypertension, Pulmonary ; metabolism ; pathology ; physiopathology ; Male ; Pulmonary Artery ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Rhodiola ; Vascular Endothelial Growth Factor A ; metabolism