Experimental hypoxemia in older and younger healthy men

1961 ◽  
Vol 16 (4) ◽  
pp. 639-640 ◽  
Author(s):  
Ernst Simonson
Keyword(s):  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Older Men ◽  
Arterial Oxygen ◽  
Healthy Men ◽  
The Difference

Arterial oxygen saturation was measured by means of an earlobe oximeter in 68 older (mean age 59.5) and 58 younger, (mean age 23.4 years) healthy men while breathing a 10% O2, 90% N2 mixture for a period of 10 min. The drop of the arterial oxygen saturation was more pronounced in the older men, and the difference in reaction was statistically highly significant. Submitted on January 9, 1961

scholarly journals Brain Blood Flow in Andean and Himalayan High-Altitude Populations: Evidence of Different Traits for the Same Environmental Constraint

2010 ◽  
Vol 31 (2) ◽  
pp. 706-714 ◽  
Author(s):  
Gerard FA Jansen ◽  
Buddha Basnyat
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Oxygen Demand ◽  
Arterial Oxygen ◽  
The Tibetan Plateau ◽  
Brain Blood Flow ◽  
Organ Systems ◽  
Andean Altiplano ◽  
The Difference

Humans have populated the Tibetan plateau much longer than the Andean Altiplano. It is thought that the difference in length of occupation of these altitudes has led to different responses to the stress of hypoxia. As such, Andean populations have higher hematocrit levels than Himalayans. In contrast, Himalayans have increased circulation to certain organ systems to meet tissue oxygen demand. In this study, we hypothesize that cerebral blood flow ( CBF) is higher in Himalayans than in Andeans. Using a MEDLINE and EMBASE search, we included 10 studies that investigated CBF in Andeans and Himalayans between 3,658 and 4,330 m altitude. The CBF values were corrected for differences in hematocrit and arterial oxygen saturation. The data of these studies show a mean hematocrit of 50% in Himalayans and 54.1% in Andeans. Arterial oxygen saturation was 86.9% in Andeans and 88.4% in Himalayans. The CBF in Himalayans was slightly elevated compared with sea-level subjects, and was 24% higher compared with Andeans. After correction for hematorit and arterial oxygen saturation, CBF was ~20% higher in Himalayans compared with Andeans. Altered brain metabolism in Andeans, and/or increased nitric oxide availability in Himalayans may have a role to explain this difference in brain blood flow.

scholarly journals Is pulse oximeter a reliable tool for non-critically ill patients with COVID-19?

2021 ◽  
Author(s):  
Aslıhan Gürün Kaya ◽  
Miraç Öz ◽  
İREM AKDEMİR KALKAN ◽  
Ezgi Gülten ◽  
güle AYDIN ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Lymphocyte Count ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Reactive Protein ◽  
Arterial Blood ◽  
The Difference ◽  
Clinical Conditions

Introduction: Guidelines recommend using a pulse oximeter rather than arterial blood gas (ABG) for COVID-19 patients. However, significant differences can be observed between oxygen saturation measured by pulse oximetry (SpO2) and arterial oxygen saturation (SaO2) in some clinical conditions. We aimed to assess the reliability of pulse oximeter in patients with COVID-19 Methods: We retrospectively reviewed ABG analyses and SpO2 levels measured simultaneously with ABG in patients hospitalized in COVID-19 wards. Results: We categorized total 117 patients into two groups; in whom the difference between SpO2 and SaO2 was 4% (acceptable difference) and >4% (large difference). Large difference group exhibited higher neutrophil count, C-reactive protein, ferritin, fibrinogen, D-dimer and lower lymphocyte count. Multivariate analyses revealed that increased fibrinogen, increased ferritin and decreased lymphocyte count were independent risk factors for large difference between SpO2 and SaO2. The total study group demonstrated the negative bias of 4.02% with the limits of agreement of −9.22% to 1.17%. The bias became significantly higher in patients with higher ferritin, fibrinogen levels and lower lymphocyte count. Conclusion: Pulse oximeters may not be sufficient to assess actual oxygen saturation especially in COVID-19 patients with high ferritin and fibrinogen levels and low lymphocyte count low SpO2 measurements.

Effect of Almitrine on Hypoxic Ventilatory Drive Measured by Transient and Progressive Isocapnic Hypoxia in Normal Men

1989 ◽  
Vol 77 (4) ◽  
pp. 431-437 ◽  
Author(s):  
M. A. A. Airlie ◽  
D. C. Flenley ◽  
P. M. Warren
Keyword(s):  
Oxygen Saturation ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Controlled Study ◽  
Peripheral Chemoreceptor ◽  
Ventilatory Drive ◽  
The Difference ◽  
Normal Men

1. In a double-blind placebo-controlled study, we have investigated the effect of the peripheral chemoreceptor stimulant drug almitrine bismesylate on hypoxic ventilatory drive (expressed as the slope of the minute ventilation/arterial oxygen saturation relationship in litres min−1 %−1) as measured by both progressive isocapnic hypoxia at rest and transient hypoxia (three breaths of 100% N2) during moderate exercise, in seven normal men, to determine if the ventilatory response to the transient hypoxic stimulus is a more specific measure of peripheral chemoreceptor sensitivity to hypoxia. 2. Hypoxic ventilatory drive measured using progressive isocapnic hypoxia ranged from −0.13 to −2.65 litres min−1 % −1 after placebo and from − 0.20 to − 6.48 litres min−1 %−1 after almitrine. The response was greater after almitrine in six of the seven subjects, and the difference was significant for the whole group (P < 0.05). 3. Hypoxic ventilatory drive measured using transient hypoxia ranged from −0.19 to −1.59 litres min−1 %−1 after placebo and from −0.09 to −1.62 litres min−1 %−1 after almitrine. The response was not consistently greater after almitrine, and the difference was not significant for the group. 4. Difficulties in accurately quantifying a brief rise in minute ventilation after transient hypoxia, particularly in subjects with a low hypoxic ventilatory drive, may have masked small changes in the slope of the minute ventilation/arterial oxygen saturation relationship with this method. However, the significant increase in the response to progressive isocapnic hypoxia after almitrine suggests that the failure to demonstrate an effect using transient hypoxic stimuli was not solely due to between-day variation in hypoxic ventilatory drive or the small numbers of subjects studied. 5. We conclude that, although transient hypoxia avoids any central depression of ventilation that might result from the prolonged hypoxia used in the conventional steady state or progressive isocapnic methods (thereby leading to underestimation of the hypoxic ventilatory drive), the ventilatory response to such transient stimuli is also affected by factors other than peripheral chemoreceptor activity.

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.

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