Modelling the relationships between arterial oxygen saturation, exercise intensity and the level of aerobic performance in acute hypoxia

2021 ◽  
Author(s):  
Xavier Woorons ◽  
Jean Paul Richalet
Keyword(s):  
Oxygen Saturation ◽  
Exercise Intensity ◽  
Acute Hypoxia ◽  
Arterial Oxygen Saturation ◽  
Aerobic Performance ◽  
Arterial Oxygen

Quantitative analysis of the effect of fraction of inspired oxygen on peripheral oxygen saturation in healthy volunteers

2020 ◽  
Author(s):  
Ji-Yeon Bang ◽  
Changhun Cho ◽  
Eun-Kyung Lee ◽  
Byung-Moon Choi ◽  
Gyu-Jeong Noh
Keyword(s):  
Oxygen Saturation ◽  
Acute Hypoxia ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Peripheral Oxygen Saturation ◽  
Turnover Model ◽  
Inhibitory Function ◽  
Short Term Exposure ◽  
Fraction Of Inspired Oxygen ◽  
Inspired Oxygen

Abstract Background The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO 2 ) and peripheral oxygen saturation (SpO 2 ) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies. We also measured the changes in biomarkers expected to be related to hypoxia (i.e., lactate, carboxyhemoglobin (COHb), and methemoglobin (MetHb)) in response to short-term exposure to hypoxia.Methods Volunteers were exposed to various levels of induced hypoxia over 70−100% arterial oxygen saturation (SaO 2 ). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO 2 and SpO 2 were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA). Lactate, COHb, and MetHb were measured using a CO-oximeter.Results In total, 2899 SpO 2 data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k out = 0.942 1/min, Imax = 0.802, IC 50 = 85.3%, γ = 27.3. The changes in SpO 2 due to decreases in FiO 2 well explained by the turnover model with inhibitory function as a sigmoidal model. As SpO 2 decreased, lactate and COHb increased as a whole, and COHb showed the best correlation (Pearson’s correlation, R 2 =0.3263, P < 0.0001).Conclusion The potency of FiO 2 required to reduce SpO 2 from 100% to 70% was 14.7%. Carboxyhemoglobin has the potential to be a useful biomarker for acute hypoxia.

scholarly journals Spleen contraction elevates hemoglobin concentration at high altitude during rest and exercise

2020 ◽  
Vol 120 (12) ◽  
pp. 2693-2704
Author(s):  
Erika Schagatay ◽  
Alexander Lunde ◽  
Simon Nilsson ◽  
Oscar Palm ◽  
Angelica Lodin-Sundström
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Arterial Oxygen Saturation ◽  
Hemoglobin Concentration ◽  
Step Test ◽  
Arterial Oxygen ◽  
Spleen Volume ◽  
Spleen Contraction ◽  
Response To Exercise ◽  
Rest And Exercise

Abstract Purpose Hypoxia and exercise are known to separately trigger spleen contraction, leading to release of stored erythrocytes. We studied spleen volume and hemoglobin concentration (Hb) during rest and exercise at three altitudes. Methods Eleven healthy lowlanders did a 5-min modified Harvard step test at 1370, 3700 and 4200 m altitude. Spleen volume was measured via ultrasonic imaging and capillary Hb with Hemocue during rest and after the step test, and arterial oxygen saturation (SaO2), heart rate (HR), expiratory CO2 (ETCO2) and respiratory rate (RR) across the test. Results Resting spleen volume was reduced with increasing altitude and further reduced with exercise at all altitudes. Mean (SE) baseline spleen volume at 1370 m was 252 (20) mL and after exercise, it was 199 (15) mL (P < 0.01). At 3700 m, baseline spleen volume was 231 (22) mL and after exercise 166 (12) mL (P < 0.05). At 4200 m baseline volume was 210 (23) mL and after exercise 172 (20) mL (P < 0.05). After 10 min, spleen volume increased to baseline at all altitudes (NS). Baseline Hb increased with altitude from 138.9 (6.1) g/L at 1370 m, to 141.2 (4.1) at 3700 m and 152.4 (4.0) at 4200 m (P < 0.01). At all altitudes Hb increased from baseline during exercise to 146.8 (5.7) g/L at 1370 m, 150.4 (3.8) g/L at 3700 m and 157.3 (3.8) g/L at 4200 m (all P < 0.05 from baseline). Hb had returned to baseline after 10 min rest at all altitudes (NS). The spleen-derived Hb elevation during exercise was smaller at 4200 m compared to 3700 m (P < 0.05). Cardiorespiratory variables were also affected by altitude during both rest and exercise. Conclusions The spleen contracts and mobilizes stored red blood cells during rest at high altitude and contracts further during exercise, to increase oxygen delivery to tissues during acute hypoxia. The attenuated Hb response to exercise at the highest altitude is likely due to the greater recruitment of the spleen reserve during rest, and that maximal spleen contraction is reached with exercise.

scholarly journals Accuracy of two pulse-oximetry measurements for INTELLiVENT-ASV in mechanically ventilated patients: a prospective observational study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinshu Katayama ◽  
Jun Shima ◽  
Ken Tonai ◽  
Kansuke Koyama ◽  
Shin Nunomiya
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Prospective Observational Study ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Arterial Blood ◽  
Ventilated Patients

AbstractRecently, maintaining a certain oxygen saturation measured by pulse oximetry (SpO2) range in mechanically ventilated patients was recommended; attaching the INTELLiVENT-ASV to ventilators might be beneficial. We evaluated the SpO2 measurement accuracy of a Nihon Kohden and a Masimo monitor compared to actual arterial oxygen saturation (SaO2). SpO2 was simultaneously measured by a Nihon Kohden and Masimo monitor in patients consecutively admitted to a general intensive care unit and mechanically ventilated. Bland–Altman plots were used to compare measured SpO2 with actual SaO2. One hundred mechanically ventilated patients and 1497 arterial blood gas results were reviewed. Mean SaO2 values, Nihon Kohden SpO2 measurements, and Masimo SpO2 measurements were 95.7%, 96.4%, and 96.9%, respectively. The Nihon Kohden SpO2 measurements were less biased than Masimo measurements; their precision was not significantly different. Nihon Kohden and Masimo SpO2 measurements were not significantly different in the “SaO2 < 94%” group (P = 0.083). In the “94% ≤ SaO2 < 98%” and “SaO2 ≥ 98%” groups, there were significant differences between the Nihon Kohden and Masimo SpO2 measurements (P < 0.0001; P = 0.006; respectively). Therefore, when using automatically controlling oxygenation with INTELLiVENT-ASV in mechanically ventilated patients, the Nihon Kohden SpO2 sensor is preferable.Trial registration UMIN000027671. Registered 7 June 2017.

scholarly journals BIOCHEMICAL STUDIES ON SHOCK

1944 ◽  
Vol 79 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Frank L. Engel ◽  
Helen C. Harrison ◽  
C. N. H. Long
Keyword(s):  
Blood Pressure ◽  
Amino Acids ◽  
Oxygen Saturation ◽  
Hepatic Artery ◽  
Arterial Oxygen Saturation ◽  
Amino Nitrogen ◽  
Arterial Oxygen ◽  
High Positive Correlation ◽  
Peripheral Tissues ◽  
Arterial Blood

1. In a series of rats subjected to hemorrhage and shock a high negative correlation was found between the portal and peripheral venous oxygen saturations and the arterial blood pressure on the one hand, and the blood amino nitrogen levels on the other, and a high positive correlation between the portal and the peripheral oxygen saturations and between each of these and the blood pressure. 2. In five cats subjected to hemorrhage and shock the rise in plasma amino nitrogen and the fall in peripheral and portal venous oxygen saturations were confirmed. Further it was shown that the hepatic vein oxygen saturation falls early in shock while the arterial oxygen saturation showed no alteration except terminally, when it may fall also. 3. Ligation of the hepatic artery in rats did not affect the liver's ability to deaminate amino acids. Hemorrhage in a series of hepatic artery ligated rats did not produce any greater rise in the blood amino nitrogen than a similar hemorrhage in normal rats. The hepatic artery probably cannot compensate to any degree for the decrease in portal blood flow in shock. 4. An operation was devised whereby the viscera and portal circulation of the rat were eliminated and the liver maintained only on its arterial circulation. The ability of such a liver to metabolize amino acids was found to be less than either the normal or the hepatic artery ligated liver and to have very little reserve. 5. On complete occlusion of the circulation to the rat liver this organ was found to resist anoxia up to 45 minutes. With further anoxia irreversible damage to this organ's ability to handle amino acids occurred. 6. It is concluded that the blood amino nitrogen rise during shock results from an increased breakdown of protein in the peripheral tissues, the products of which accumulate either because they do not circulate through the liver at a sufficiently rapid rate or because with continued anoxia intrinsic damage may occur to the hepatic parenchyma so that it cannot dispose of amino acids.

Arterial Oxygen Saturation and Posture in Acute Stroke

1993 ◽  
Vol 22 (4) ◽  
pp. 269-272 ◽  
Author(s):  
JIMMY ELIZABETH ◽  
JOSEPH SINGARAYAR ◽  
JOHN ELLUL ◽  
DAVID BARER ◽  
MICHAEL LYE
Keyword(s):  
Oxygen Saturation ◽  
Acute Stroke ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen

scholarly journals Rapid Clinical and Radiological Improvement in a Patient with Severe COVID-19 Infection Treated with Convalescent Plasma

Reports ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 15
Author(s):  
Stephen Malnick ◽  
Waleed Ghannam ◽  
Adam Abu Sharb ◽  
Pavel Alin
Keyword(s):  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Breathing Room

The COVID-19 pandemic has affected more than 100 million people worldwide. One of the major presentations is pneumonia. Patients are classified as severe when they have an arterial oxygen saturation of less than 94% on breathing room air. We present a case of a healthy 29-year-old man who had severe COVID-19 pneumonia and responded dramatically to two doses of convalescent plasma. This case underlines the importance of administering the plasma in the first few days of the disease.

Effect of subcutaneous arterial pulsation on determination of cerebral arterial oxygen saturation using NIRS

2000 ◽  
Author(s):  
Ralph J. F. Houston ◽  
Jan Menssen ◽  
Marco C. van der Sluijs ◽  
Willy N. Colier ◽  
Berend Oeseburg
Keyword(s):  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Pulsation

Intermittent hypoxia increases ventilation and SaO2 during hypoxic exercise and hypoxic chemosensitivity

2001 ◽  
Vol 90 (4) ◽  
pp. 1431-1440 ◽  
Author(s):  
Keisho Katayama ◽  
Yasutake Sato ◽  
Yoshifumi Morotome ◽  
Norihiro Shima ◽  
Koji Ishida ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Minute Ventilation ◽  
Acute Hypoxia ◽  
Arterial Oxygen Saturation ◽  
Submaximal Exercise ◽  
Arterial Oxygen ◽  
Hypoxic Exposure ◽  
Hypoxic Ventilatory Response ◽  
Ventilatory Equivalent ◽  
Hypoxic Exercise

The purpose of this study was 1) to test the hypothesis that ventilation and arterial oxygen saturation (SaO2 ) during acute hypoxia may increase during intermittent hypoxia and remain elevated for a week without hypoxic exposure and 2) to clarify whether the changes in ventilation and SaO2 during hypoxic exercise are correlated with the change in hypoxic chemosensitivity. Six subjects were exposed to a simulated altitude of 4,500 m altitude for 7 days (1 h/day). Oxygen uptake (V˙o 2), expired minute ventilation (V˙e), and SaO2 were measured during maximal and submaximal exercise at 432 Torr before (Pre), after intermittent hypoxia (Post), and again after a week at sea level (De). Hypoxic ventilatory response (HVR) was also determined. At both Post and De, significant increases from Pre were found in HVR at rest and in ventilatory equivalent for O2(V˙e/V˙o 2) and SaO2 during submaximal exercise. There were significant correlations among the changes in HVR at rest and inV˙e/V˙o 2 and SaO2 during hypoxic exercise during intermittent hypoxia. We conclude that 1 wk of daily exposure to 1 h of hypoxia significantly improved oxygenation in exercise during subsequent acute hypoxic exposures up to 1 wk after the conditioning, presumably caused by the enhanced hypoxic ventilatory chemosensitivity.

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