scholarly journals Superimposition of carbon dioxide on acute isobaric hypoxia: plasma erythropoietin, acid-base status, and P/sub 50/ in the unanesthetized rabbit

1978 ◽  
Author(s):  
J. Wolf-Priessnitz
Keyword(s):  
Carbon Dioxide ◽  
Acid Base ◽  
Unanesthetized Rabbit ◽  
Acid Base Status

scholarly journals Contrast‐enhanced ultrasound imaging can be used to evaluate fetal cerebral perfusion: potential implications for fetal surgery

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kendall M. Lawrence ◽  
Barbara E. Coons ◽  
Anush Sridharan ◽  
Avery C. Rossidis ◽  
Marcus G. Davey ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cerebral Perfusion ◽  
Fetal Surgery ◽  
Time Dependent ◽  
Contrast Enhanced Ultrasound ◽  
Acid Base ◽  
Fetal Sheep ◽  
Contrast Enhanced ◽  
Support Device ◽  
Acid Base Status

Abstract Background Fetal surgery is increasingly performed to correct congenital defects. Currently, fetal brain perfusion cannot be assessed intra-operatively. The purpose of this study was to determine if contrast-enhanced ultrasound (CEUS) could be used to monitor fetal cerebral perfusion during fetal surgery and if parameters correlate with fetal hemodynamics or acid/base status. Methods Cannulated fetal sheep were insufflated with carbon dioxide gas in an extra-uterine support device and in utero to mimic fetal surgery. Fetal heart rate, mean arterial pressure, and arterial blood gases were serially measured. CEUS examinations of the brain were performed and time-dependent metrics were quantified to evaluate perfusion. The relationships between measured parameters were determined with mixed linear effects models or two-way repeated measures analysis of variance. Results 6 fetal sheep (113 ± 5 days) insufflated at multiple time-points (n = 20 experiments) in an extra-uterine support device demonstrated significant correlations between time-dependent perfusion parameters and fetal pH and carbon dioxide levels. In utero, 4 insufflated fetuses (105 ± 1 days) developed hypercarbic acidosis and had reductions in cerebral perfusion parameters compared to age-matched controls (n = 3). There was no significant relationship between cerebral perfusion parameters and fetal hemodynamics. Conclusions CEUS-derived cerebral perfusion parameters can be measured during simulated fetal surgery and strongly correlate with fetal acid/base status.

The Acid-Base Status of the Blood of the Developing Chick Embryo

1969 ◽  
Vol 50 (1) ◽  
pp. 79-86
Author(s):  
C. DAWES ◽  
K. SIMKISS
Keyword(s):  
Carbon Dioxide ◽  
Chick Embryo ◽  
Base Excess ◽  
Carbon Dioxide Tension ◽  
Chick Embryos ◽  
Acid Base ◽  
A Value ◽  
Acid Base Status

1. The pH, carbon dioxide tension, bicarbonate and base excess levels of chick embryos have been measured during the period of 11 days of incubation until the 2nd day post hatching. 2. The carbon dioxide tension rises continuously from a value of about 20 mm. Hg on day 11 to a maximum of almost 60 mm. Hg on day 19. 3. The bicarbonate content rises rapidly from the 12th day (16 m-equiv./l.) until the 16th day (33 m-equiv./l.). 4. The pH falls to minimum values on the 13-14th day and the 19th day. 5. These variations are discussed in relation to the physiology of the developing embryo and its acid-base metabolism.

scholarly journals Contrast-enhanced Ultrasound Imaging Can be Used to Evaluate Fetal Cerebral Perfusion: Potential Implications for Fetal Surgery

2020 ◽  
Author(s):  
Kendall M Lawrence ◽  
Barbara E Coons ◽  
Anush Sridha ◽  
Avery C Rossidis ◽  
Marcus G Davey ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cerebral Perfusion ◽  
Fetal Surgery ◽  
Time Dependent ◽  
Contrast Enhanced Ultrasound ◽  
Acid Base ◽  
Fetal Sheep ◽  
Contrast Enhanced ◽  
Support Device ◽  
Acid Base Status

Abstract Background: Fetal surgery is increasingly performed to correct congenital defects. Currently, fetal brain perfusion cannot be assessed intra-operatively. The purpose of this study was to determine if contrast-enhanced ultrasound (CEUS) could be used to monitor fetal cerebral perfusion during fetal surgery and if parameters correlate with fetal hemodynamics or acid/base status. Methods: Cannulated fetal sheep were insufflated with carbon dioxide gas in an extra-uterine support device and in utero to mimic fetal surgery. Fetal heart rate, mean arterial pressure, and arterial blood gases were serially measured. CEUS examinations of the brain were performed and time-dependent metrics were quantified to evaluate perfusion. The relationships between measured parameters were determined with mixed linear effects models or two-way repeated measures analysis of variance. Results: 6 fetal sheep (113 ± 5 days) insufflated at multiple time-points (n=20 experiments) in an extra-uterine support device demonstrated significant correlations between time-dependent perfusion parameters and fetal pH and carbon dioxide levels. In utero, 4 insufflated fetuses (105 ± 1 days) developed hypercarbic acidosis and had reductions in cerebral perfusion parameters compared to age-matched controls (n=3). There was no significant relationship between cerebral perfusion parameters and fetal hemodynamics. Conclusions: CEUS-derived cerebral perfusion parameters can be measured during simulated fetal surgery and strongly correlate with fetal acid/base status.

Relative effects of carbonic anhydrase infusion or inhibition on carbon dioxide transport and acid-base status in the sea lamprey Petromyzon marinus following exercise

1996 ◽  
Vol 199 (4) ◽  
pp. 933-940
Author(s):  
B Tufts ◽  
S Currie ◽  
J Kieffer
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Venous Blood ◽  
Extracellular Fluid ◽  
Respiratory Acidosis ◽  
Acid Base ◽  
Carbon Dioxide Transport ◽  
Co2 Transport ◽  
Arterial Blood ◽  
Acid Base Status

In vivo experiments were carried out to determine the relative effects of carbonic anhydrase (CA) infusion or inhibition on carbon dioxide (CO2) transport and acid-base status in the arterial and venous blood of sea lampreys recovering from exhaustive exercise. Infusion of CA into the extracellular fluid did not significantly affect CO2 transport or acid-base status in exercised lampreys. In contrast, infusion of the CA inhibitor acetazolamide resulted in a respiratory acidosis in the blood of recovering lampreys. In acetazolamide-treated lampreys, the post-exercise extracellular pH (pHe) of arterial blood was significantly lower than that in the saline-infused (control) lampreys. The calculated arterial and venous partial pressure of carbon dioxide (PCO2) and the total CO2 concentration in whole blood (CCO2wb) and red blood cells (CCO2rbc) during recovery in the acetazolamide-infused lampreys were also significantly greater than those values in the saline-infused control lampreys. These results suggest that the CO2 reactions in the extracellular compartment of lampreys may already be in equilibrium and that the access of plasma bicarbonate to CA is probably not the sole factor limiting CO2 transport in these animals. Furthermore, endogenous red blood cell CA clearly has an important role in CO2 transport in exercising lampreys.

Temperature-induced changes in blood acid-base status in the alligator, Alligator mississipiensis

1978 ◽  
Vol 45 (6) ◽  
pp. 922-926 ◽  
Author(s):  
D. G. Davies
Keyword(s):  
Carbon Dioxide ◽  
Body Temperature ◽  
Minute Ventilation ◽  
Carbon Dioxide Production ◽  
Carbon Dioxide Partial Pressure ◽  
Acid Base ◽  
Arterial Blood ◽  
Acid Base Status ◽  
Body Temperature Increase ◽  
Alligator Mississipiensis

Gas exchange and arterial blood acid-base status were measured in 13 conscious alligators, Alligator mississipiensis, at 15, 25, and 35 degrees C. Arterial pH decreased by 0.250 units (from 7.635 to 7.385) and arterial carbon dioxide partial pressure increased by 11.4 Torr (from 11.8 to 23.2) as body temperature increased from 15 to 35 degrees C. No statistically significant changes occurred in arterial bicarbonate concentration. When OH-/H+ and alpha-imidazole were compared at each temperature, more variability was observed in OH-/H+, which increased from 8.7 to 12.0 as temperature increased from 15 to 35 degrees C. alpha-Imidazole remained essentially constant (0.76 at 15 degrees C and 0.80 at 35 degrees C). Body temperature increase caused marked increases in minute ventilation (VE), oxygen consumption (VO2), and carbon dioxide production (VCO2). The relative changes in these parameters resulted in a decrease in both VE/VO2 and VE/VCO2. The data of the present study are consistent with the concept that poikilotherms regulate their alveolar ventilation with changes in body temperature in order to keep OH-/H+ or alpha-imidazole constant.

Effects of amniodistention with carbon dioxide on fetal acid-base status during fetoscopic surgery in a sheep model

2001 ◽  
Vol 15 (4) ◽  
pp. 368-372 ◽  
Author(s):  
E. Gratacós ◽  
J. Wu ◽  
R. Devlieger ◽  
M. Van de Velde ◽  
J. A. Deprest
Keyword(s):  
Carbon Dioxide ◽  
Acid Base ◽  
Sheep Model ◽  
Acid Base Status

Control of breathing in uremia: ventilatory response to CO2 after hemodialysis

1976 ◽  
Vol 41 (2) ◽  
pp. 216-222 ◽  
Author(s):  
R. W. Hamilton ◽  
P. E. Epstein ◽  
L. W. Henderson ◽  
N. H. Edelman ◽  
A. P. Fishman
Keyword(s):  
Carbon Dioxide ◽  
Ventilatory Response ◽  
Respiratory Alkalosis ◽  
Similar Increase ◽  
Acid Base ◽  
Plasma Urea ◽  
Acid Base Status ◽  
Uremic Patients ◽  
Plasma Urea Concentration ◽  
Ventilatory Response To Co2

The mechanisms responsible for the transient respiratory alkalosis which follows clinical hemodialysis were evaluated by studying the ventilatory response to carbon dioxide in chronic uremic patients, and in unanesthetized normal and chronic uremic goats. A significant increase in sensitivity to CO2 was found in acidotic uremic patients immediately (within 30 min) following hemodialysis (P less than 0.01). Sensitivity to CO2 returned to the predialysis value within 24 h. Lung volume and maximal breathing capacity were unchanged. A similar increase in sensitivity to CO2 was seen in nonacidotic uremic goats following hemodialysis. In the goats, these changes in sensitivity could not be explained by changes in cerebrospinal fluid acid-base status. Adding sufficient urea to the dialysate to prevent a fall in plasma urea concentration, eliminated this increase in sensitivity to CO2 in both uremic patients and goats. These results suggests that the transient respiratory alkalosis following hemodialysis is due to an increase in the sensitivity of the ventilatory response to carbon dioxide and is a consequence of dialysis-induced osmotic disequilibrium.

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