Role of central chemoreceptors in behavioral thermoregulation of the toad, Bufo marinus

1994 ◽  
Vol 266 (5) ◽  
pp. R1483-R1487 ◽  
Author(s):  
L. G. Branco ◽  
S. C. Wood
Keyword(s):  
Body Temperature ◽  
Oxygen Saturation ◽  
Fourth Ventricle ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Behavioral Thermoregulation ◽  
Peripheral Stimulus ◽  
Central Chemoreceptors ◽  
Selected Body Temperature

We tested the hypothesis that hypercapnia will induce behavioral hypothermia in toads and that central chemoreceptors are involved in this response. Animals were tested in an enclosed temperature gradient supplied with different gas mixtures. Fractional inspired CO2 (FICO2) between 0 and 0.05 had no significant effect on selected body temperature, but FICO2 between 0.06 and 0.10 reduced the selected body temperature from U approximately 28 to 18 degrees C. To determine if the hypercapnia-induced hypothermia is mediated by acidification of central chemoreceptors, the pH of the fourth ventricle was kept constant by perfusion with mock cerebrospinal fluid of pH 7.7 or 7.1 (normal and acidic values, respectively). Ventricular perfusion at pH 7.7 under normocapnic conditions had no effect on body temperature. Hypercapnia (FICO2 0.08) failed to induce hypothermia when the fourth ventricle was kept at pH 7.7 and when hyperoxia was present. Acidic ventricular perfusion under normocapnic conditions decreased selected body temperature from 27 to 25 degrees C, a significant drop but much less than that due to hypercapnia producing the same brain pH, suggesting an important role of peripheral chemoreceptors. The physiological significance of behavioral hypothermia and nature of the peripheral stimulus were evaluated by measuring the effect of hypercapnia on arterial oxygen saturation, PO2, and pH at 15 and 25 degrees C. Arterial oxygen saturation was higher at the lower temperature. Increasing FICO2 decreased oxygen saturation at 25 degrees C but not at 15 degrees C. Arterial PO2 increased with increasing inspired CO2. This increase was greater at 15 degrees C than at 25 degrees C. Arterial pH decreased at both temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Association between Regional Tissue Oxygenation and Body Temperature in Term and Preterm Infants Born by Caesarean Section

Children ◽  
2020 ◽  
Vol 7 (11) ◽  
pp. 205
Author(s):  
Marlies Bruckner ◽  
Lukas P. Mileder ◽  
Alisa Richter ◽  
Nariae Baik-Schneditz ◽  
Bernhard Schwaberger ◽  
...  
Keyword(s):  
Body Temperature ◽  
Caesarean Section ◽  
Oxygen Saturation ◽  
Preterm Infants ◽  
Near Infrared ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Secondary Outcome ◽  
Tissue Oxygen Saturation ◽  
Preterm Neonates

Body temperature (BT) management remains a challenge in neonatal intensive care, especially during resuscitation after birth. Our aim is to analyze whether there is an association between the BT and cerebral and peripheral tissue oxygen saturation (crSO2/cTOI and prSO2), arterial oxygen saturation (SpO2), and heart rate (HR). The secondary outcome parameters of five prospective observational studies are analyzed. We include preterm and term neonates born by Caesarean section who received continuous pulse oximetry and near-infrared spectroscopy monitoring during the first 15 min, and a rectal BT measurement once in minute 15 after birth. Four-hundred seventeen term and 169 preterm neonates are included. The BT did not correlate with crSO2/cTOI and SpO2. The BT correlated with the HR in all neonates (ρ = 0.210, p < 0.001) and with prSO2 only in preterm neonates (ρ = −0.285, p = 0.020). The BT was lower in preterm compared to term infants (36.7 [36.4–37.0] vs. 36.8 [36.6–37.0], p = 0.001) and prevalence of hypothermia was higher in preterm neonates (29.5% vs. 12.0%, p < 0.001). To conclude, the BT did not correlate with SpO2 and crSO2/cTOI, however, there was a weak positive correlation between the BT and the HR in the whole cohort and a weak correlation between the BT and prSO2 only in preterm infants. Preterm neonates had a statistically lower BT and suffered significantly more often from hypothermia during postnatal transition.

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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