Blood respiratory properties in pigeons at high altitudes: effects of acclimation

1985 ◽  
Vol 249 (6) ◽  
pp. R765-R775 ◽  
Author(s):  
Y. Weinstein ◽  
M. H. Bernstein ◽  
P. E. Bickler ◽  
D. V. Gonzales ◽  
F. C. Samaniego ◽  
...  
Keyword(s):  
High Altitude ◽  
Venous Blood ◽  
Hypoxia Tolerance ◽  
Control Group ◽  
Mixed Venous Blood ◽  
High Altitudes ◽  
Simulated High Altitude ◽  
O2 Extraction ◽  
Columbia Livia ◽  
Venous Blood Gas

Many birds thrive at high altitudes where environmental temperatures are low. Previous studies have shown that tolerance of and acclimation to hypoxia involve cardiopulmonary and hematological adaptations. We investigated blood respiratory properties during exposure to simulated high altitude (hypobaric hypoxia) and low temperature in unanesthetized resting pigeons (Columbia livia, mean mass 0.38 kg). A control group (C) and a group acclimated to 7 km above sea level (ASL) in a hypobaric chamber at 25 degrees C (HA group) were used. All were acutely exposed to altitudes through 9 km ASL at 5 or 25 degrees C. Arterial and mixed venous blood gas tensions and O2 and CO2 content during steady state decreased with increased altitude, whereas blood lactate increased in both groups at both temperatures. Acute high-altitude exposure did not affect hematocrit, hemoglobin concentrations, or O2 carrying capacity, but at any altitude these were all greater in HA than in C birds. At 5 degrees C blood pH increased with altitude in controls but remained unchanged in HA birds. At 25 degrees C in both groups mean intracellular pH did not change, averaging 6.97, whereas extracellular (venous) pH increased with altitude. At the highest altitudes tissue O2 extraction was virtually complete in both groups. Acclimation changed blood O2 and CO2 combining properties in ways likely to improve gas transport at high altitudes. The previously unreported shifts in blood respiratory and acid-base properties with acclimation indicate that innate extrapulmonary adaptations contribute to avian hypoxia tolerance.

Mixed venous blood gas sampling is not influenced by the speed of withdrawal in cardiac surgery patients

2004 ◽  
Vol 30 (10) ◽  
pp. 1969-1973 ◽  
Author(s):  
Emmanuel Sirdar ◽  
Jean-Gilles Guimond ◽  
Isabelle Coiteux ◽  
Sylvain B�lisle ◽  
Denis Babin ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Blood Gas ◽  
Gas Sampling ◽  
Venous Blood Gas ◽  
Mixed Venous

Pathological supply dependence of O2 uptake during bacteremia in dogs

1987 ◽  
Vol 63 (4) ◽  
pp. 1487-1492 ◽  
Author(s):  
D. P. Nelson ◽  
C. Beyer ◽  
R. W. Samsel ◽  
L. D. Wood ◽  
P. T. Schumacker
Keyword(s):  
Bacterial Infection ◽  
Venous Blood ◽  
Extraction Ratio ◽  
Control Group ◽  
Systemic Delivery ◽  
O2 Uptake ◽  
Critical Limit ◽  
Peripheral Tissues ◽  
O2 Extraction ◽  
O2 Delivery

When systemic delivery of O2 [QO2 = cardiac output X arterial O2 content (CaO2)] is reduced, the systemic O2 extraction ratio [(CaO2-concentration of O2 in venous blood/CaO2] increases until a critical limit is reached below which O2 uptake (VO2) becomes limited by delivery. Many patients with adult respiratory distress syndrome exhibit supply dependence of VO2 even at high levels of QO2, which suggests that a peripheral O2 extraction defect may be present. Since many of these patients also suffer from serious bacterial infection, we tested the hypothesis that bacteremia might produce a similar defect in the ability of tissues to maintain VO2 independent of QO2, as QO2 reduced. The critical O2 delivery (QO2crit) and critical extraction ratio (ERcrit) were compared in a control group of dogs and a group receiving a continuous infusion of Pseudomonas aeruginosa (5 x 10(7) organisms/min). Dogs were anesthetized, paralyzed, and ventilated with room air. Systemic QO2 was reduced in stages by hemorrhage as hematocrit was maintained. At each stage, systemic VO2 and QO2 were measured, and the critical point was determined from a plot of VO2 vs. QO2. The mean QO2crit and ERcrit of the bacteremic group (11.4 +/- 2.2 ml.min-1.kg-1 and 0.51 +/- 0.09) were significantly different from control (7.4 +/- 1.2 and 0.71 +/- 0.10) (P less than 0.05). These results suggest that bacterial infection can reduce the ability of peripheral tissues to extract O2 from a limited supply, causing VO2 to become limited by O2 delivery at a stage when a smaller fraction of the delivered O2 has been extracted.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Arterial and Mixed Venous Blood Gas Tensions in Exercising Ducks

1980 ◽  
Vol 59 (4) ◽  
pp. 914-917 ◽  
Author(s):  
J.P. KILEY ◽  
W.D. KUHLMANN ◽  
M.R. FEDDE
Keyword(s):  
Venous Blood ◽  
Mixed Venous Blood ◽  
Blood Gas ◽  
Venous Blood Gas ◽  
Mixed Venous

Body fluid and hematologic changes in the toad exposed to 48 h of simulated high altitude

1981 ◽  
Vol 51 (4) ◽  
pp. 794-797 ◽  
Author(s):  
H. M. Biswas ◽  
P. B. Patra ◽  
M. C. Boral
Keyword(s):  
High Altitude ◽  
Plasma Volume ◽  
Body Fluid ◽  
Extracellular Fluid ◽  
Control Group ◽  
Bufo Melanostictus ◽  
Simulated High Altitude ◽  
Volume Blood ◽  
Total Body ◽  
Toad Bufo

Body fluid and hematologic changes were found in three groups of adult male toads that had been exposed to 48 h of continuous simulated altitudes of 12,000, 18,000, and 24,000 ft, respectively. Erythrocyte counts and hematocrit ratios were increased significantly in all the high-altitude-exposed animals compared with the control group of animals kept at sea level, whereas the hemoglobin concentrations were significantly increased only in the 18,000- and 24,000-ft-exposed animals. Exposure to high altitude generally caused a reduction of plasma volume, blood volume, extracellular fluid volume, and total body water. These reductions were markedly lower in the animals exposed to 24,000 ft. These simulated high-altitude effects on body fluids and hematology in the toad (Bufo melanostictus) were compared with those of the rat, birds, and humans acutely acutely exposed at various high altitudes and were found to be qualitatively similar.

Influence of hematocrit ratio on survival of unacclimatized dogs at simulated high altitude

1963 ◽  
Vol 205 (6) ◽  
pp. 1172-1174 ◽  
Author(s):  
Elvin E. Smith ◽  
Jack W. Crowell
Keyword(s):  
High Altitude ◽  
Carrying Capacity ◽  
Simulated Altitude ◽  
High Altitudes ◽  
Survival Group ◽  
Closed Chamber ◽  
Atmospheric Air ◽  
Simulated High Altitude ◽  
Nitrogen Ratio ◽  
Oxygen Carrying Capacity

Eighty-six dogs were subjected to acutely induced, simulated high altitudes to determine the optimum hematocrit ratio for survival. High altitudes were simulated by diluting atmospheric air with nitrogen. Dogs with various hematocrit ratios were obtained by natural selection, hemorrhage, transfusion, and pretreatment with phenylhydrazine. Fifty-one dogs, in groups of 5–15, were placed in a closed chamber, and a 40,000-ft altitude was simulated by proper adjustment of the oxygen-to-nitrogen ratio. This altitude was maintained for a period of 6 hr. Most dogs with hematocrits less than 24 or greater than 66 died before the simulated altitude of 40,000 ft was attained; those with hematocrits of 24–30 survived from 1/2 to 5 hr. Some dogs with hematocrits of 30–65 survived the entire 7-hr period. However, no dogs with hematocrits from 37 to 54 died. The same procedures were repeated at a simulated altitude of 50,000 ft with a group of 38 dogs. The survival group was composed of dogs with hematocrits of 36–46. Dogs with hematocrits of 40–41 were conscious and active while those with hematocrits on either side of this value were comatose. These data indicate that the optimum hematocrit for survival of the unacclimatized dog at acutely induced high altitude is about 40. Deaths occurring on both sides of the optimum value may be explained by a simultaneous consideration of the curves depicting oxygen-carrying capacity of the blood, and blood viscosity, at all ranges of hematocrit.

scholarly journals Histogenous Hypoxia and Acid Retention in Schizophrenia: Changes in Venous Blood Gas Analysis and SOD in Acute and Stable Schizophrenia Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Xingbing Huang ◽  
Qiu-Ling Lu ◽  
Xiu-Mei Zhu ◽  
Yi-Bin Zeng ◽  
Yun Liu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Venous Blood ◽  
Fasting Blood Glucose ◽  
Downward Trend ◽  
Control Group ◽  
Healthy Controls ◽  
Blood Gas ◽  
Stable Period ◽  
Significant Difference ◽  
Venous Blood Gas

Background: Oxidative stress may play an important role in the pathogenesis of schizophrenia (SCH), and there is considerable indirect evidence that hypoxia is closely related to SCH, but direct evidence of hypoxia in SCH has never been found.Methods:In this study, superoxide dismutase (SOD), venous blood gas, and Positive and Negative Syndrome Scale (PANSS) were examined in 40 SCH patients and compared with those of 40 healthy controls. The patients were treated with combination of atypical antipsychotics and Ditan Huayu Lishen decoction (a Chinese medicine decoction) and examined in the acute and stable period, respectively. Comparisons of indicators between two groups were performed using an independent-samples t-test, comparison of indicators between the acute and stable periods in the SCH group was performed using paired-samples t-test. Pearson correlation and multiple linear regression analyses were performed to investigate the relationships between the effect indicators.Results: Higher venous pH, PvO2, and fasting blood glucose levels and lower SOD, lactic acid, and PvCO2 levels were found in SCH patients compared with the control group; SOD was negatively correlated with the general psychopathology subscale score (PANSS-G), and PvO2 levels were closely related to venous pH in SCH and related to PvCO2 in the control group. It was also found that SOD activity showed no significant difference in acute and stable period, whereas PvO2 showed a downward trend, and venous pH was decreased significantly after treatment. Both the venous pH and PvO2 were higher in patients with SCH than that in healthy controls.Conclusion: It suggests that histogenous hypoxia and acid retention exist in relation to SCH, and there is an improvement of acid retention and a downward trend in histogenous hypoxia after combination treatment. Venous pH, PvO2, and PvCO2 are trait variables, but not state variables of SCH. The theory of histogenous hypoxia and acid retention can well explain the decrease in pH value and the increase in lactic acid in brain tissue of patients with SCH. Histogenous hypoxia and acid retention closely related to glucose metabolism. So they may play an important role in pathophysiology for SCH.

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