scholarly journals Ratio of venous-to-arterial PCO2 to arteriovenous oxygen content difference during regional ischemic or hypoxic hypoxia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jihad Mallat ◽  
Benoit Vallet
Keyword(s):  
Metabolic Acidosis ◽  
Oxygen Content ◽  
Anaerobic Metabolism ◽  
Experimental Models ◽  
Tissue Hypoxia ◽  
Hypoxic Hypoxia ◽  
Arterial Pco2 ◽  
Mechanically Ventilated ◽  
Content Difference ◽  
The Difference

AbstractThe purpose of the study was to evaluate the behavior of the venous-to-arterial CO2 tension difference (ΔPCO2) over the arterial-to-venous oxygen content difference (ΔO2) ratio (ΔPCO2/ΔO2) and the difference between venous-to-arterial CO2 content calculated with the Douglas’ equation (ΔCCO2D) over ΔO2 ratio (ΔCCO2D/ΔO2) and their abilities to reflect the occurrence of anaerobic metabolism in two experimental models of tissue hypoxia: ischemic hypoxia (IH) and hypoxic hypoxia (HH). We also aimed to assess the influence of metabolic acidosis and Haldane effects on the PCO2/CO2 content relationship. In a vascularly isolated, innervated dog hindlimb perfused with a pump-membrane oxygenator system, the oxygen delivery (DO2) was lowered in a stepwise manner to decrease it beyond critical DO2 (DO2crit) by lowering either arterial PO2 (HH-model) or flow (IH-model). Twelve anesthetized and mechanically ventilated dogs were studied, 6 in each model. Limb DO2, oxygen consumption ($${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 ), ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 were obtained every 15 min. Beyond DO2crit, $${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 decreased, indicating dysoxia. ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 increased significantly only after reaching DO2crit in both models. At DO2crit, ΔPCO2/ΔO2 was significantly higher in the HH-model than in the IH-model (1.82 ± 0.09 vs. 1.39 ± 0.06, p = 0.002). At DO2crit, ΔCCO2D/ΔO2 was not significantly different between the two groups (0.87 ± 0.05 for IH vs. 1.01 ± 0.06 for HH, p = 0.09). Below DO2crit, we observed a discrepancy between the behavior of the two indices. In both models, ΔPCO2/ΔO2 continued to increase significantly (higher in the HH-model), whereas ΔCCO2D/ΔO2 tended to decrease to become not significantly different from its baseline in the IH-model. Metabolic acidosis significantly influenced the PCO2/CO2 content relationship, but not the Haldane effect. ΔPCO2/ΔO2 was able to depict the occurrence of anaerobic metabolism in both tissue hypoxia models. However, at very low DO2 values, ΔPCO2/ΔO2 did not only reflect the ongoing anaerobic metabolism; it was confounded by the effects of metabolic acidosis on the CO2–hemoglobin dissociation curve, and then it should be interpreted with caution.

scholarly journals Venoarterial PCO2-to-arteriovenous oxygen content difference ratio is a poor surrogate for anaerobic metabolism in hemodilution: an experimental study

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Arnaldo Dubin ◽  
Gonzalo Ferrara ◽  
Vanina Siham Kanoore Edul ◽  
Enrique Martins ◽  
Héctor Saúl Canales ◽  
...  
Keyword(s):  
Experimental Study ◽  
Oxygen Content ◽  
Anaerobic Metabolism ◽  
Content Difference

PCO2 measurements in surface proximal tubules and peritubular capillaries of the rat kidney

1982 ◽  
Vol 242 (1) ◽  
pp. F78-F85 ◽  
Author(s):  
F. J. Gennari ◽  
C. R. Caflisch ◽  
C. Johns ◽  
D. A. Maddox ◽  
J. J. Cohen
Keyword(s):  
Metabolic Acidosis ◽  
Rat Kidney ◽  
Respiratory Alkalosis ◽  
Proximal Tubules ◽  
Surface Structures ◽  
Peritubular Capillary ◽  
Acid Base ◽  
Arterial Pco2 ◽  
Peritubular Capillaries ◽  
The Difference

PCO2 was measured in surface proximal tubules and peritubular capillaries in the rat under normal acid-base conditions and in three settings with decreased HCO3(-) reabsorption: benzolamide administration, respiratory alkalosis, and metabolic acidosis. Under normal conditions, PCO2 in the early proximal tubule (EP) was 10.5 mmHg higher than PaCO2 (P less than 0.001) and 3-4 mmHg higher than late proximal (LP) and peritubular capillary (PC) PCO2 (P less than 0.001). PCO2 in LP and PC was 7 mmHg higher than PaCO2 (P less than 0.001). Benzolamide (3 mg/kg) had no effect on the difference between PC and arterial PCO2 or between EP and PC PCO2. Increasing benzolamide to 8 mg/kg increased PCO2 in the surface structures relative to arterial PCO2 by 3-5 mmHg (P less than 0.01). Metabolic acidosis did not alter the relationships between cortical and arterial PCO2. By contrast, respiratory alkalosis decreased cortical PCO2 relative to PaCO2 by over 50%. Nonetheless, EP PCO2 was still higher than LP or PC PCO2 (P less than 0.01). Thus, reducing HCO3(-) reabsorption does not obliterate the difference between EP and LP or PC PCO2 nor does it invariably reduce PCO2 in the surface structures of the kidney relative to arterial PCO2.

scholarly journals Anaerobic Metabolism and Metabolic Acidosis During Cardiopulmonary Bypass

1961 ◽  
Vol 153 (4) ◽  
pp. 499-506 ◽  
Author(s):  
WALTER F. BALLINGER ◽  
HEINZ VOLLENWEIDER ◽  
LOUIS PIERUCCI ◽  
JOHN Y. TEMPLETON
Keyword(s):  
Metabolic Acidosis ◽  
Cardiopulmonary Bypass ◽  
Anaerobic Metabolism

Brain pH responses to sodium bicarbonate and Carbicarb during systemic acidosis

1989 ◽  
Vol 256 (5) ◽  
pp. H1316-H1321 ◽  
Author(s):  
J. I. Shapiro ◽  
M. Whalen ◽  
R. Kucera ◽  
N. Kindig ◽  
G. Filley ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
Sodium Bicarbonate ◽  
Ammonium Chloride ◽  
Respiratory Acidosis ◽  
Arterial Pco2 ◽  
Bicarbonate Therapy ◽  
Brain Ph ◽  
Dose Dependent ◽  
Intracellular Alkalinization

Rats subjected to ammonium chloride-induced metabolic acidosis or respiratory acidosis caused by hypercapnia were given alkalinization therapy with either sodium bicarbonate or Carbicarb. Ammonium chloride induced dose-dependent systemic acidosis but did not affect intracellular brain pH. Hypercapnia caused dose-dependent systemic acidosis as well as decreases in intracellular brain pH. Sodium bicarbonate treatment resulted in systemic alkalinization and increases in arterial PCO2 in both acidosis models, but it caused intracellular brain acidification in rats with ammonium chloride acidosis. Carbicarb therapy resulted in systemic alkalinization without major changes in arterial PCO2 and intracellular brain alkalinization in both acidosis models. These data demonstrate that bicarbonate therapy of systemic acidosis may be associated with "paradoxical" intracellular brain acidosis, whereas Carbicarb causes both systemic and intracellular alkalinization under conditions of fixed ventilation.

Gas exchange in dogs in the prone and supine positions

1992 ◽  
Vol 72 (6) ◽  
pp. 2292-2297 ◽  
Author(s):  
K. C. Beck ◽  
J. Vettermann ◽  
K. Rehder
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Prone Position ◽  
Pulmonary Blood Flow ◽  
Random Order ◽  
Arterial Pco2 ◽  
Supine Posture ◽  
Pulmonary Shunting ◽  
The Difference ◽  
Arterial Po2

To determine the cause of the difference in gas exchange between the prone and supine postures in dogs, gas exchange was assessed by the multiple inert gas elimination technique (MIGET) and distribution of pulmonary blood flow was determined using radioactively labeled microspheres in seven anesthetized paralyzed dogs. Each animal was studied in the prone and supine positions in random order while tidal volume and respiratory frequency were kept constant with mechanical ventilation. Mean arterial PO2 was significantly lower (P less than 0.01) in the supine [96 +/- 10 (SD) Torr] than in the prone (107 +/- 6 Torr) position, whereas arterial PCO2 was constant (38 Torr). The distribution of blood flow (Q) vs. ventilation-to-perfusion ratio obtained from MIGET was significantly wider (P less than 0.01) in the supine [ln SD(Q) = 0.75 +/- 0.26] than in the prone position [ln SD (Q) = 0.34 +/- 0.05]. Right-to-left pulmonary shunting was not significantly altered. The distribution of microspheres was more heterogeneous in the supine than in the prone position. The larger heterogeneity was due in part to dorsal-to-ventral gradients in Q in the supine position that were not present in the prone position (P less than 0.01). The decreased efficiency of oxygenation in the supine posture is caused by an increased ventilation-to-perfusion mismatch that accompanies an increase in the heterogeneity of Q distribution.

scholarly journals Compared the Microbiota Profiles between Samples from Bronchoalveolar Lavage and Endotracheal Aspirates in Severe Pneumonia: A Real-World Experience

2022 ◽  
Vol 11 (2) ◽  
pp. 327
Author(s):  
Yeong-Nan Cheng ◽  
Wei-Chih Huang ◽  
Chen-Yu Wang ◽  
Pin-Kuei Fu
Keyword(s):  
Microbial Community ◽  
Bronchoalveolar Lavage ◽  
Microbial Community Composition ◽  
Severe Pneumonia ◽  
Metagenomic Sequencing ◽  
Microbial Composition ◽  
Icu Patients ◽  
Mechanically Ventilated ◽  
The Difference ◽  
New Onset

Lower respiratory tract sampling from endotracheal aspirate (EA) and bronchoalveolar lavage (BAL) are both common methods to identify pathogens in severe pneumonia. However, the difference between these two methods in microbiota profiles remains unclear. We compared the microbiota profiles of pairwise EA and BAL samples in ICU patients with respiratory failure due to severe pneumonia. We prospectively enrolled 50 ICU patients with new onset of pneumonia requiring mechanical ventilation. EA and BAL were performed on the first ICU day, and samples were analyzed for microbial community composition via 16S rRNA metagenomic sequencing. Pathogens were identified in culture medium from BAL samples in 21 (42%) out of 50 patients. No difference was observed in the antibiotic prescription pattern, ICU mortality, or hospital mortality between BAL-positive and BAL-negative patients. The microbiota profiles in the EA and BAL samples are similar with respect to diversity, microbial composition, and microbial community correlations. The antibiotic treatment regimen was rarely changed based on the BAL findings. The samples from BAL did not provide more information than EA in the microbiota profiles. We suggest that EA is more useful than BAL for microbiome identification in mechanically ventilated patients.

Dynamics of respiratory gas exchange during exercise after correction of congenital heart disease

1996 ◽  
Vol 80 (2) ◽  
pp. 458-463 ◽  
Author(s):  
T. Reybrouck ◽  
L. Mertens ◽  
N. Kalis ◽  
M. Weymans ◽  
M. Dumoulin ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Aerobic Exercise ◽  
Congenital Heart ◽  
Anaerobic Metabolism ◽  
Assessment Method ◽  
Co2 Production ◽  
Ventilatory Anaerobic Threshold ◽  
The Difference ◽  
Response To Exercise

In pediatric exercise testing, conventional measures of aerobic exercise function such as maximal O2 uptake or the ventilatory anaerobic threshold (VAT) use only one value for the assessment of exercise capacity. We studied a more comprehensive approach to evaluate aerobic exercise function by analyzing the steepness of the slope of CO2 production (VCO2) vs. VO2 above the VAT (S3). This was calculated in 32 patients operated on for congenital heart disease [16 for transposition of the great arteries (TGA) and 16 for tetralogy of Fallot (TF)] and was compared with 16 age-matched controls (nl). The results show that the reproducibility of this new assessment method was excellent (coefficient of variation for S3: 8.6%). S3 was significantly steeper (P<0.05) in the patients (1.31 +/- 0.22 for TGA and 1.28 +/- 0.16 for TF) compared with the nl (1.10 +/- 0.22). Also, the difference between S3 and the slope of VCO2 vs. VO2 below the VAT was significantly higher in the patients (0.37 +/- 0.22 for TGA and 0.31 +/- 0.10 for TF) than in controls (0.22 +/- 0.06). The steeper slopes were associated with lower than normal values for VAT and O2 during exercise. It is concluded that the analysis of the steepness of the slope of CO2 is a sensitive, reproducible, and objective approach to evaluate the integrative cardiopulmonary response to exercise. It complements the assessment of a subnormal VAT by reflecting the extent of anaerobic metabolism.

Splanchnic hemodynamics in portal-hypertensive rats: measurement with gamma-labeled microspheres

1982 ◽  
Vol 242 (2) ◽  
pp. G156-G160 ◽  
Author(s):  
R. J. Groszmann ◽  
J. Vorobioff ◽  
E. Riley
Keyword(s):  
Blood Flow ◽  
Portal Vein ◽  
Experimental Models ◽  
Hypertensive Rats ◽  
Venous Flow ◽  
Reliable Technique ◽  
Splanchnic Hemodynamics ◽  
Significant Difference ◽  
Normal Rat ◽  
The Difference

A method to quantitate hepatic arterial flow (HA), portal venous flow (PBF), and blood flow through portal-systemic shunts (ShBF) in portal-hypertensive rats is described. This method relies on the injection of two differently radiolabeled microspheres (15 micrometers) into the left ventricle and spleen. To evaluate the usefulness of this technique, studies were performed on normal, cirrhotic, and portal vein-ligated rats anesthetized with ketamine. With this method, PBF is calculated indirectly from the sums of the blood flow of the splanchnic organs that drain into the portal vein. In the portal-hypertensive animals with portal-systemic shunting, this technique allows for the determination of PBF perfusing the liver [hepatic fraction of portal flow (HFP)] and PBF escaping through portal-systemic shunts (ShBF). The portal vein-ligated rats have higher HA flow (0.68 +/- 0.08 ml . min-1 . g-1) and lower HFP (0.08 +/- 0.01 ml . min-1 . g-1) than either the cirrhotic (HA: 0.27 +/- 0.03 ml . min-1 . g-1, P less than 0.01; HFP: 1.20 +/- 0.20 ml . min-1 . g-1, P less than 0.01) or the normal rat (HA: 0.29 +/- 0.06 ml . min-1 . g-1, P less than 0.01; HFP: 1.39 +/- 0.16 ml . min-1 . g-1, P less than 0.01). No significant difference was found between the cirrhotic and normal rats. The ShBF was higher in the portal vein-ligated rats (21.4 +/- 2.8 ml/min) than in the cirrhotic (4.6 +/- 2.5 ml/min, P less than 0.001) or normal rats (0.03 +/- 0.005 ml/min, P less than 0.01). The difference between the cirrhotic and normal animals was also significant (P less than 0.05). This is a simple, rapid, and reliable technique that allows for the quantitation of splanchnic hemodynamics in experimental models with portal hypertension.

Treatment of Skin Injury due to Vinorelbine Extravasation Using bFGF and rhGM-CSF: An Experimental Study in a Murine Model

2010 ◽  
Vol 13 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Chunhua Yu ◽  
Jin Wang ◽  
Yan Fu ◽  
Yongqiu Mao ◽  
Yongshun Chen ◽  
...  
Keyword(s):  
Murine Model ◽  
Maximum Size ◽  
Experimental Models ◽  
Control Group ◽  
Skin Injury ◽  
Macrophage Colony Stimulating Factor ◽  
The Difference ◽  
Macrophage Colony ◽  
And Control

Background and objective: A murine model of skin injury from vinorelbine extravasation was established to evaluate the treatment efficacy of basic fibroblast growth factor (bFGF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). Materials and method: Experimental models were divided into bFGF, rhGM-CSF, and control (saline) groups, with 40 mice in each group. Edema and ulceration were measured on Days 1, 3, 5, 7, 10, 14, and 18 after the onset of extravasation; injuries were examined pathomorphologically in three mice/group/time point. Results: Edema reached maximum size on Day 3 in the bFGF and rhGM-CSF groups and Day 5 in the control group. The difference between the two experimental groups was not significant; differences between the control group and the experimental groups were statistically significant at all time points. Edema and ulceration began to improve on Day 10 in the bFGF and rhGM-CSF groups and Day 18 in the control group. Healing duration was 14—18 days in the experimental groups, with a (not significantly) shorter duration in the bFGF group. Healing was completed by Day 27.5 in the control group. Pathomorphological evaluation showed regular reepithelization and newly formed granulation tissue in the bFGF and rhGM-CSF groups on Day 13. In the control group, wounds were partially healed, edema and shallow ulcers existed, and epithelization was fragile and disorganized on Day 18. Conclusions: bFGF and rhGM-CSF are useful for the treatment of skin injury due to vinorelbine extravasation, but bFGF may be slightly more effective in decreasing time and improving quality of healing.

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