The Influence of Altitude on Erythropoietin Resistance Index in Maintenance Hemodialysis Patients: Data from Tibetan Plateau

2020 ◽  
pp. 1-6
Author(s):  
Yan Wang ◽  
Zong-hui Dang ◽  
Liang-ying Gan ◽  
Ciren Luobu ◽  
Lei Zhang ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Resistance Index ◽  
Hemoglobin Concentration ◽  
Maintenance Hemodialysis ◽  
Autonomous Region ◽  
Tibet Autonomous Region ◽  
Dialysis Vintage ◽  
Peking University ◽  
The Impact

Background: It is known that hypoxia influences many of the biologic processes involved in erythropoiesis; therefore, the high-altitude hypoxia may affect erythropoietin (EPO) responsiveness in maintenance hemodialysis (MHD) patients. This study aimed to evaluate the impact of altitude on EPO responsiveness in MHD patients. Methods: In this retrospective study, MHD patients from Tibet Autonomous Region People’s Hospital (3,650 m above sea level) and Peking University People’s Hospital (43.5 m above sea level) were recruited between May 2016 and December 2018. Patients were divided into 2 groups according to altitude. Variables including age, sex, dialysis vintage, dialysis modality, duration of EPO use, EPO doses, and laboratory tests were collected and analyzed. EPO responsiveness was measured in terms of the EPO resistance index (ERI). ERI was defined as the weekly weight-adjusted dose of EPO (IU/kg/week) divided by hemoglobin concentration (g/dL). The association between ERI and altitude was estimated using a multivariable linear regression model. Results: Sixty-two patients from Tibet Autonomous Region People’s Hospital (high-altitude [HA] group) and 102 patients from Peking University People’s Hospital (low-altitude [LA] group) were recruited. The ERI for HA group and LA group was 6.9 ± 5.1 IU w−1 kg−1 (g/dL)−1 and 11.5 ± 6.4 IU w−1 kg−1 (g/dL)−1, respectively. After adjusting for covariates by multivariable regression, altitude was independently associated with ERI (R2 = 0.245, p < 0.001). Conclusion: Altitude had an independent negative correlation with ERI. This result supported the hypothesis that altitude-associated hypoxia improved EPO responsiveness in MHD patients.

scholarly journals Hypoxia Modulates Platelet Purinergic Signalling Pathways

2019 ◽  
Vol 120 (02) ◽  
pp. 253-261 ◽  
Author(s):  
Gordon G. Paterson ◽  
Jason M. Young ◽  
Joseph A. Willson ◽  
Christopher J. Graham ◽  
Rebecca C. Dru ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Platelet Reactivity ◽  
Clinical Importance ◽  
Adenosine Diphosphate ◽  
Purinergic Signalling ◽  
Systematic Assessment ◽  
Vasp Phosphorylation ◽  
The Impact ◽  
Induced Aggregation

Abstract Background Hypoxia resulting from ascent to high-altitude or pathological states at sea level is known to increase platelet reactivity. Previous work from our group has suggested that this may be adenosine diphosphate (ADP)-specific. Given the clinical importance of drugs targeting ADP pathways, research into the impact of hypoxia on platelet ADP pathways is highly important. Methods Optimul aggregometry was performed on plasma from 29 lowland residents ascending to 4,700 m, allowing systematic assessment of platelet reactivity in response to several platelet agonists. Aggregometry was also performed in response to ADP in the presence of inhibitors of the two main ADP receptors, P2Y1 and P2Y12 (MRS2500 and cangrelor, respectively). Phosphorylation of vasodilator-stimulated phosphoprotein (VASP), a key determinant of platelet aggregation, was analysed using the VASPFix assay. Results Hypobaric hypoxia significantly reduced the ability of a fixed concentration of cangrelor to inhibit ADP-induced aggregation and increased basal VASP phosphorylation. However, in the absence of P2Y receptor inhibitors, we did not find evidence of increased platelet sensitivity to any of the agonists tested and found reduced sensitivity to thrombin receptor-activating peptide-6 amide. Conclusion Our results provide evidence of increased P2Y1 receptor activity at high altitude and suggest down-regulation of the P2Y12 pathway through increased VASP phosphorylation. These changes in ADP pathway activity are of potential therapeutic significance to high-altitude sojourners and hypoxic sea level patients prescribed platelet inhibitors and warrant further investigation.

Reduced coagulation at high altitude identified by thromboelastography

2012 ◽  
Vol 107 (06) ◽  
pp. 1066-1071 ◽  
Author(s):  
Daniel Martin ◽  
Jim Pate ◽  
Andre Vercueil ◽  
Patrick Doyle ◽  
Michael Mythen ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
High Altitude ◽  
Sea Level ◽  
Whole Blood ◽  
Maximum Amplitude ◽  
Peripheral Oxygen Saturation ◽  
Blood Samples ◽  
Whole Blood Samples ◽  
Α Angle ◽  
The Impact

SummaryThe impact of hypoxaemia on blood coagulation remains unclear despite use of a variety of measures to address the issue. We report the first use of thromboelastography (TEG) at high altitude to describe the dynamics of clot formation in whole blood samples. Seventeen healthy volunteers ascended to 5,300 m following an identical ascent profile; TEG measurements at 4,250 m and 5,300 m were compared with those from sea level. Peripheral oxygen saturation (SpO2) and haematocrit were also measured. Ascent resulted in a decline in SpO2 from 97.8 (± 1.2) % at sea level to 86.9 (± 3.3) % at 4,250 m and 79.5 (± 5.8) % at 5,300 m (p<0.001); haematocrit rose from 43.7 (± 2.8) % at sea level, to 46.7 (± 3.9) % and 52.6 (± 3.2) % at 4,250 m and 5,300 m, respectively (p<0.01). TEG reaction (R)-time and kinetic (K)-time were both increased at 5,300 m compared to sea level, 8.95 (± 1.37) minutes (min) to 11.69 (± 2.91) min (p=0.016) and 2.40 (± 0.66) min to 4.99 (± 1.67) min (p<0.001), respectively. Additionally the alpha (α)- angle was decreased from 57.7 (± 8.2) to 51.6 (± 6.4) (p<0.001). There was no change in maximum amplitude (MA) on ascent to altitude. These changes are consistent with an overall pattern of slowed coagulation at high altitude.

Effects of erythrocyte infusion on VO2max at high altitude

1996 ◽  
Vol 81 (1) ◽  
pp. 252-259 ◽  
Author(s):  
A. J. Young ◽  
M. N. Sawka ◽  
S. R. Muza ◽  
R. Boushel ◽  
T. Lyons ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Treadmill Running ◽  
Control Group ◽  
O2 Uptake ◽  
Control Subjects ◽  
And Control ◽  
Experimental Group

This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P < 0.01) arterial hematocrit, hemoglobin concentration, and arterial O2 content in the erythrocyte-infused subjects. By HA9, there were no longer any differences in hematocrit, hemoglobin concentration, or arterial O2 content between groups. No change in VO2max occurred between HA1 and HA9 for either group. Thus, despite increasing arterial O2-carrying capacity, autologous erythrocyte infusion did not ameliorate the decrement in VO2max at 4,300-m altitude.

Hemoglobin at High Altitude as Related to Age

1963 ◽  
Vol 9 (6) ◽  
pp. 710-716 ◽  
Author(s):  
D B Dill ◽  
J W Terman ◽  
F G Hall
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Blood Volume ◽  
Early Phase ◽  
Hemoglobin Concentration ◽  
The Other ◽  
Other Hand

Abstract During the summer of 1962 the early phase of acclimatization to high altitude was studied in 6 of those who participated in the international high-altitude expedition to Chile in 1935. Ages of the 6 ranged from 58 to 71. Two also had taken part in a high-altitude study in 1929. In their earlier years these subjects had had an increase in hemoglobin concentration beginning with their arrival at high altitude. This response has been well established, especially by the Pike's Peak party led by Haldane and the work of Hurtado and associates in Peru. On the other hand, 5 of the 6 in the 1962 party exhibited a decrease in hemoglobin concentration during the first few days. The greatest decrease was observed in the oldest subject. His hemoglobin was 88% of his sea level value after 9 days at altitude and remained below his sea level value for another week. No observations were made on blood volume; hence, we can only speculate regarding possible related changes.

DEVELOPMENT AND CHANGE IN RURAL TIBET

Asian Survey ◽  
2003 ◽  
Vol 43 (5) ◽  
pp. 758-779 ◽  
Author(s):  
Melvyn C. Goldstein ◽  
Ben Jiao ◽  
Cynthia M. Beall ◽  
Phuntsog Tsering
Keyword(s):  
Quantitative Methods ◽  
Autonomous Region ◽  
Qualitative And Quantitative ◽  
Rural Change ◽  
Qualitative And Quantitative Methods ◽  
Tibet Autonomous Region ◽  
The Impact ◽  
The Tibet Autonomous Region

Abstract This article reports on a multi-year study of the impact of China's reform policies since the early 1980s on rural change in the Tibet Autonomous Region. The study was conducted with 780 households in 13 villages, using qualitative and quantitative methods.

Internal carotid and vertebral arterial flow velocity in men at high altitude

1987 ◽  
Vol 63 (1) ◽  
pp. 395-400 ◽  
Author(s):  
S. Y. Huang ◽  
L. G. Moore ◽  
R. E. McCullough ◽  
R. G. McCullough ◽  
A. J. Micco ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Flow Velocity ◽  
Sea Level ◽  
Internal Carotid ◽  
Hemoglobin Concentration ◽  
Subsequent Increase ◽  
O2 Transport ◽  
Flow Velocities

Cerebral blood flow increases at high altitude, but the mechanism of the increase and its role in adaptation to high altitude are unclear. We hypothesized that the hypoxemia at high altitude would increase cerebral blood flow, which would in turn defend O2 delivery to the brain. Noninvasive Doppler ultrasound was used to measure the flow velocities in the internal carotid and the vertebral arteries in six healthy male subjects. Within 2–4 h of arrival on Pikes Peak (4,300 m), velocities in both arteries were slightly and not significantly increased above sea-level values. By 18–44 h a peak increase of 20% was observed (combined P less than 0.025). Subsequently (days 4–12) velocities declined to values similar to those at sea level. At altitude the lowest arterial O2 saturation (SaO2) and the highest end-tidal PCO2 was observed on arrival. By day 4 and thereafter, when the flow velocities had returned toward sea-level values, hemoglobin concentration and SaO2 were increased over initial high-altitude values such that calculated O2 transport values were even higher than those at sea level. Although the cause of the failure for cerebral flow velocity to increase on arrival is not understood, the subsequent increase may act to defend brain O2 transport. With further increase in hemoglobin and SaO2 over time at high altitude, flow velocity returned to sea-level values.

Thermal Performance Prediction for High Power Processors at High Altitude

2005 ◽  
Author(s):  
Guoping Xu
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Thermal Performance ◽  
High Power ◽  
Air Flow ◽  
Measurement Data ◽  
Correction Factors ◽  
Flow Impedance ◽  
Impedance Curve ◽  
The Impact

A method to predict high power processor thermal performance in air-cooled electronic systems at high altitude is proposed in this paper. This method employs non-dimensional heat transfer and fluid flow parameters to evaluate the impact of high altitude conditions based on measurement data at sea level. Experimental data including fan/fan tray curve, system air flow impedance and processor heat sink performance for various air flow rates at sea level are required for the analysis. Altitude correction factors will be derived from nondimensional correlations. By using these altitude correction factors, the dimensional fan curve, system air flow impedance curve, and thermal performance curve may all be transformed from sea-level to high altitude. The proposed method can be applied to thermal performance predictions of forced convection electronic components with or without air-cooled heat sinks. The method can be used in a system with any flow regime: laminar, turbulent or a combination of both. This method will be demonstrated through an example of a high end server system.

Stage racing at altitude induces hemodilution despite an increase in hemoglobin mass

2014 ◽  
Vol 117 (5) ◽  
pp. 463-472 ◽  
Author(s):  
Laura A. Garvican-Lewis ◽  
Yorck O. Schumacher ◽  
Sally A. Clark ◽  
Ryan Christian ◽  
Paolo Menaspà ◽  
...  
Keyword(s):  
Sea Level ◽  
Repeated Measures ◽  
Venous Blood ◽  
Hemoglobin Concentration ◽  
Regulatory Mechanisms ◽  
Intense Exercise ◽  
Altitude Exposure ◽  
Hemoglobin Mass ◽  
The Impact ◽  
Over Time

Plasma volume (PV) can be modulated by altitude exposure (decrease) and periods of intense exercise (increase). Cycle racing at altitude combines both stimuli, although presently no data exist to document which is dominant. Hemoglobin mass (Hbmass), hemoglobin concentration ([Hb]), and percent reticulocytes (%Retics) of altitude (ALT; n = 9) and sea-level (SL; n = 9) residents were measured during a 14-day cycling race, held at 1,146–4120 m, as well as during a simulated tour near sea level (SIM; n = 12). Hbmass was assessed before and on days 9 and 14 of racing. Venous blood was collected on days 0, 3, 6, 10, and 14. PV was calculated from Hbmass and [Hb]. A repeated-measures ANOVA was used to assess the impact of racing at altitude over time, within and between groups. [Hb] decreased significantly in all groups over time ( P < 0.0001) with decreases evident on the third day of racing. %Retics increased significantly in SL only ( P < 0.0001), with SL values elevated at day 6 compared with prerace ( P = 0.02), but were suppressed by the end of the race ( P = 0.0002). Hbmass significantly increased in SL after 9 ( P = 0.0001) and 14 ( P = 0.008) days of racing and was lower at the end of the race than midrace ( P = 0.018). PV increased in all groups ( P < 0.0001). Multiday cycle racing at altitude induces hemodilution of a similar magnitude to that observed during SL racing and occurs in nonacclimatized SL residents, despite an altitude-induced increase in Hbmass. Osmotic regulatory mechanisms associated with intense exercise appear to supersede acute enhancement of oxygen delivery at altitude.

scholarly journals Responses of developmental and physiological traits to manipulated incubation conditions in broiler embryos at hypoxic high altitude

2018 ◽  
Vol 61 (3) ◽  
pp. 337-349 ◽  
Author(s):  
Elif Babacanoğlu
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Water Loss ◽  
Incubation Temperature ◽  
Hemoglobin Concentration ◽  
Physiological Traits ◽  
Control Group ◽  
Broiler Breeders ◽  
Incubation Condition ◽  
Hatching Eggs

Abstract. The effects of hypoxia at increased altitude levels on the cardio-respiratory development of broiler embryos are distinct in comparison with those at sea level. The aim of the study was to investigate the effects of high incubation temperature (H) and oxygen supplementation (O) during hypoxic high altitude (HA) on developmental and physiological traits of embryos and hatching performance of embryonated hatching eggs in broilers at different embryonic stages. A total of 1280 eggs obtained from broiler breeders laid at sea level were used. Eggshell quality characteristics were measured for 20 eggs. The rest of the 1260 eggs were divided into seven incubation condition (IC) groups (180 eggs per group) including a control group at 37.8 ∘C and 21 % O2; O groups, with daily 1 h 23.5 % O2 supplementation at 37.8 ∘C as O0−11, O12−21, and O18−21; H groups at 38.5 ∘C high incubation temperature at 21 % O2 as H0−11, H12−21, and H18−21 from days 0 to 11, 12 to 21, and 18 to 21 of incubation, respectively. All groups were incubated in three different incubators at hypoxic HA. The effect of IC was determined on eggshell temperature, hatching performance, embryo development, right ventricular (RV) to total ventricular (TV) ratio, and blood parameters. The highest egg water loss and embryonic mortality and the lowest hatchability were in the H0−11 group, which depended on increased eggshell temperature during incubation. On day 18 of incubation, due to the decreased egg water loss in the O12−21 and O18−21 groups, there was an increase in hatchability in fertile eggs similar to the middle and late H groups. Towards the end of incubation, embryo/chick weights were not different and RV and TV weights increased in the treated groups, and the RV ∕ TV ratio changed between 15 and 26 %. At hatching, yolk sac weight increased in H0−11 and H12−21 groups. The O groups had the lowest serum tri-iodothyronine (T3) concentration as distinct from H groups. The serum thyroxine (T4) concentration increased in the treated groups, dependent on sex of the embryo. Blood hemoglobin concentration of O groups decreased relative to other groups. The hematocrit value was the lowest in the O12−21 and highest in the H12−21 groups. The H and O treatments during pre-hatch hypoxic HA condition can be positively evaluated on physiological traits of embryos after half of incubation depended on the timing of the IC exposure to the hatching eggs obtained from broiler breeders at sea level.

scholarly journals The Impact of Fluid Resuscitation on Hemodynamic of Hemorrhagic Shock: An Animal Model Experimental Study

2020 ◽  
Author(s):  
Antonius Hocky Pudjiadi ◽  
Agus Firmansyah ◽  
Gunanti Soeyono ◽  
Saptawati Bardosono ◽  
Sri Widia Jusman ◽  
...  
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Fluid Resuscitation ◽  
Normal Saline ◽  
Oxygen Delivery ◽  
Resistance Index ◽  
Hemoglobin Concentration ◽  
Volume Resuscitation ◽  
Lung Water ◽  
The Impact

Abstract Background: To investigate the effect of fluid resuscitation on glycocalyx shedding, and extravascular lung water index (ELWI), mean arterial pressure (MAP) and oxygen delivery (DO2) changes.Methods: Male domestic piglets (Sus scrofa) 6-10 weeks old anesthetized and bled until mean arterial pressure drop to 20% of baseline and resuscitated with normal saline as much as blood drowned, followed with 40 mL/kg of normal saline after 30 minutes. Cardiac index (CI), ELWI, systemic vascular resistance index (SVRI), MAP, atrial natriuretic peptide (ANP) and syndecan-1 were measured before and after each fluid resuscitations. Results: Serum ANP was increased after normal volume fluid resuscitation (p= 0.043) and return its baseline value after hypervolemia fluid resuscitation. Serum Syndecan-1 levels did not increase. A small increase in ELWI only found 60 minutes after fluid resuscitation (p= 0.021). SVRI undergo a gradual decrease, until the lowest value at hypervolemia volume resuscitation. There was no difference between the MAP of the two groups (p= 0.105). Hemoglobin concentration significantly decreased from normal to hypervolemia volume resuscitation (p= 0.009). Oxygen delivery in hypervolemia resuscitation is higher than in normal volume resuscitation (p= 0.012), due to a significant increase in CI at hypervolemia volume resuscitation (p<0.001).Conclusions: Hypervolemia fluid resuscitation in the animal hemorrhage model is not induced glycocalyx shedding. Small increase ELWI was found in 60 minutes after fluid resuscitation. DO2 is maintained by increasing CI in spite of decreasing hemoglobin level due to hemodilution. Increasing CI is balanced by reducing SVRI to sustain stable MAP.

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