Take home figureAdapted from Bartsch and Gibbs2 Physiological response to hypoxia. Life-sustaining oxygen delivery, in spite of a reduction in the partial pressure of inhaled oxygen between 25% and 60% (respectively at 2500 m and 8000 m), is ensured by an increase in pulmonary ventilation, an increase in cardiac output by increasing heart rate, changes in vascular tone, as well as an increase in haemoglobin concentration. BP, blood pressure; HR, heart rate; PaCO2, partial pressure of arterial carbon dioxide.

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Clinical recommendations for high altitude exposure of individuals with pre-existing cardiovascular conditions: A joint statement by the European Society of Cardiology, the Council on Hypertension of the European Society of Cardiology, the European Society of Hypertension, the International Society of Mountain Medicine, the Italian Society of Hypertension and the Italian Society of Mountain Medicine.

Objective: To explore the correlations between RBCs indexes and the basic coagulation parameters, and provide data for further studies on high altitude-induced thrombotic disease.Methods: A total o...

https://www.tandfonline.com/doi/pdf/10.1080/16078454.2019.1568658

Correlation between RBC changes and coagulation parameters in high altitude population.

Objective 
According to the international guidelines, fresh frozen plasma (FFP) is unanimously used to treat coagulation disorders. The quality of FFP is critical for the clinical transfusion. Till now, few studies have integratedly evaluated the differences of FFP from blood donors at between high altitude (HA) and low altitude (LA). Besides, there were no special quality standards for HA FFP in China.


Materials and methods 
Up to 41 HA (Lhasa, 3700 m) and 46 LA (Chengdu, 500 m) blood donors were included in our study to estimate the differences of FFP from HA and LA blood donors. The concentration of total plasma proteins, prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), fibrinogen (Fbg), factor (F) II, FV, FVII, FVIII, FIX, FX, FXI, FXII, D-dimer, protein C (PC), protein S (PS), antithrombin III (ATIII) and von Willebrand factor antigen (vWF:Ag) were determined, respectively.


Results 
As compared with FFP of LA blood donors, the total protein content of HA blood donors showed a significant decrease (65.2±8.9 vs.57.2±6.3 g/L; p<0.001); PT, aPTT, TT were significantly increased (p<0.001); the levels of FII, FV, FVII, FVIII, FIX, FX, FXI, FXII and vWF:Ag were notably decreased (all p<0.05), whereas Fbg and D-dimer were dramaticly increased (p = 0.038). Additionly, in HA blood donors, vWF: Ag and FVIII:C of O-group was significantly lower (p<0.05) than that of non-O-group. It should be noted that FVIII:C of HA blood donors (0.64±0.10 IU/mL) was lower than the current Chinese quality requirements for FFP (≥ 0.7 IU/ml). No significant differences were observed in PC, PS and ATIII.


Conclusion 
In general, our findings showed that the quality of FFP was significantly different between HA and LA blood donors, and the current Chinese quality requirements of FFP are not suitable for HA FFP. Therefore, setting up a special quality requirement for HA is quite necessary and meaningful.

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The quality changes in fresh frozen plasma of the blood donors at high altitude.

The objective of this study was to explore the value of ultrasound-guided percutaneous microwave thermoablation to treat secondary hyperparathyroidism (SHPT). One hundred and thirty-eight parathyroid glands from 56 patients with SHPT were ablated in this study. All the parathyroid glands were evaluated by real-time contrast-enhanced ultrasound before, during and after ablation. Changes in serum parathyroid hormone (sPTH) levels were measured before treatment and at 1 h, 1 wk, 1 mo and 6 mo after thermoablation treatment. All 56 cases had a 1-mo follow-up, and 34 cases had a 6-mo follow-up. The sPTH level of the 54 cases 1 mo after ablation was significantly lower than that before (p 0.05). Ultrasound-guided percutaneous microwave thermoablation is a feasible and effective non-surgical alternative treatment for SHPT patients.

Efficacy of Ablation Therapy for Secondary Hyperparathyroidism by Ultrasound Guided Percutaneous Thermoablation.

Objectives The current study aimed to determine whether acute hypoxia exposure in laboratory conditions associated with exercise induces an increase in systemic blood pressure (BP) in normotensive and hypertensive patients, and whether hypertensive patients are more prone to develop severe acute mountain sickness (sAMS). Finally, to determine if BP changes at exercise in acute hypoxia in hypertensive patients are predictive factors for sAMS. Methods From 2012 to 2015, 852 normotensive and 106 hypertensive patients went through an acute hypoxia exercise test before a sojourn at high altitude. A subgroup of 228 normotensive was selected to match age, sex ratio, body weight and BMI and compared with the hypertensive group. Results In normotensive and hypertensive patients, for a given workload, BP was higher in hypoxia than in normoxia, whereas, for a given heart rate, it was lower in hypoxia than in normoxia. Hypertensive patients treated by beta-blockers showed lower arterial oxygen saturation (vs. other treatments) and blunted cardiac and ventilatory responses to hypoxia at exercise. Based on questionnaires filled out at high altitude, hypertensive patients were not more prone than normotensive patients to develop sAMS. During the laboratory acute hypoxic exercise test, hypertensive patients suffering from sAMS, although taking acetazolamide showed similar BP than hypertensive patients without sAMS and without acetazolamide. Discussion and conclusion We hypothesize that acute hypoxia with exercise in laboratory conditions induces a peripheral vasodilation that balances vasoconstriction and tachycardia centrally induced through the adrenergic system. Hypertensive and normotensive patients behave similarly during exercise in acute hypoxia. Acute hypoxia does not exacerbate the exercise-induced increase in BP. BP variation, during the acute hypoxia exercise test, is not a useful predictor of intolerance to high altitude. Based on laboratory tests in acute hypoxia, hypertensive patients may not be at higher risk to develop sAMS at high altitude.

Systemic blood pressure at exercise in hypoxia in hypertensive and normotensive patients.

Excessive elevation of arterial blood pressure (BP) at high altitude can be detrimental to our health due to acute mountain sickness (AMS) or some AMS symptoms. This prospective and observational study aimed to elucidate blood pressure changes induced by exposure to high-altitude hypoxia and the relationships of these changes with AMS prevalence, AMS severity, sleep quality and exercise condition in healthy young men. A prospective observational study was performed in 931 male young adults exposed to high altitude at 3,700 m (Lhasa) from low altitude (LA, 500 m). Blood pressure measurement and AMS symptom questionnaires were performed at LA and on day 1, 3, 5, and 7 of exposure to high altitude. Lake Louise criteria were used to diagnose AMS. Likewise, the Athens Insomnia Scale (AIS) and the Epworth Sleepiness Scale (ESS) were filled out at LA and on day 1, 3, and 7 of exposure to high altitude. After acute exposure to 3,700 m, diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) rose gradually and continually (P   0.05). Poor sleeping quality was generally associated with higher SBP or DBP at high altitude, although inconsistent results were obtained at different time (P < 0.05). SBP and Pulse BP increased noticeably after high-altitude exercise (P < 0.05). Our data demonstrate notable blood pressure changes under exposure to different high-altitude conditions: 1) BP increased over time. 2) Higher BP generally accompanied poor sleeping quality and higher incidence of AMS. 3) SBP and Pulse BP were higher after high-altitude exercise. Therefore, we should put more effort into monitoring BP after exposure to high altitude in order to guard against excessive increases in BP.

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Correlation between blood pressure changes and AMS, sleeping quality and exercise upon high-altitude exposure in young Chinese men

Objectives 　To investigate the changes in arterial blood pressure in the healthy lowlanders when they were exposed to different altitudes and duration, and the relationship of the exposure with the prevalence and susceptibility of acute mountain sickness (AMS), in order to evaluate the significance of arterial blood pressure changes in the diagnosis of AMS and its clinical risk. Methods 　Demographic data and blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial BP (MABP)] of healthy lowlanders (inhabitants in ≤500m) were collected after being exposed to 3700m on day 1, 3, 5 and 7, and also after being exposed to 4400m on day 5, while healthy young men living at low altitude were randomly selected as the control group. Simultaneously the AMS symptoms Questionnaire was filled. The Lake Louise acute mountain sickness scoring system (LLS) was used to diagnose AMS. The changes in arterial blood pressure in people above and its correlation with AMS were analyzed. Results 　After acute exposure to 3700m (day 1), SBP, DBP and MABP rose obviously, and then descended moderately after adaptation for about a week, but still higher than that of LA level (P<0.05). And then SBP, DBP and MABP rose again at high-altitude of 4400m, but lower than the levels of day 1 at 3700m. MABP at 3700m and 4400m were related to LLS (r=0.138, P=0.048; r=0.145, P=0.045, respectively). MABP levels for diagnosis of AMS at 3700m showed an cut-off point of 98.5mmHg with sensitivity of 32.8% and specificity of 73.7% (P<0.05), and MABP levels for diagnosis of AMS at 4400m showed an cut-off point of 97.8mmHg with sensitivity of 42.4% and specificity of 75.5% (P<0.05). Conclusions 　After exposure to acute hypoxia, MABP may serve as a predictive parameter for diagnosis of AMS. However, the clinical application of MABP as a diagnostic criterion is limited because of its poor specificity or sensitivity. The use of MABP as a diagnostic criterion should be combined with other indicators such as arterial blood oxygen saturation (SaO2) for the diagnosis of AMS.
		
		DOI: 10.11855/j.issn.0577-7402.2014.03.12

http://www.plamj.org/index.php/plamj/article/download/907/901

Yang Liu

Papers

Correlation between blood pressure changes and AMS, sleeping quality and exercise upon high-altitude exposure in young Chinese men

Correlation analysis of the changes in arterial blood pressure in people with acute mountain sickness when exposed to high altitude