Oxygen and carbon dioxide permeability of subcutaneous pockets

1962 ◽  
Vol 202 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Hugh D. Van Liew
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Surface Area ◽  
Uptake Rate ◽  
Permeability Coefficient ◽  
Exchange Coefficient ◽  
Adjacent Tissue ◽  
Permeability Coefficients ◽  
Tissue Tension

Uptake rate of a gas from a rat's subcutaneous gas pocket was divided by the surface area and by the apparent pocket-to-tissue tension difference to yield an exchange coefficient, K'. Values in (ml x 10–4)/(min cm2 atm) were O2, 6.6; CO2, 150; and N2, 2. Blood flow in adjacent tissue appeared to have little influence on uptakes of O2 and CO2, since the K'co2:K'o2 ratio indicated that the uptakes were governed by diffusion alone, and drastic alteration of blood flow (death of the animal) decreased K'o2 by only 10%. In contrast, blood flow apparently affected N2 uptake. Because O2 and CO2 uptakes were not blood flow limited, K'o2 and K'co2 are estimates of true permeability coefficients; the calculated permeability coefficient for N2 is 3.3 (ml x 10–4)/(min cm2 atm). Comparison shows the pocket surface to be 1/50–1/150 as effective for O2 transfer as the lung. Finally, corrections are calculated for pocket-to-tissue pO2 and pCO2 differences in gas pockets used for tissue tonometry.

scholarly journals Developing Eco-Friendly and Cost-Effective Porous Adsorbent for Carbon Dioxide Capture

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1962
Author(s):  
Mahboubeh Nabavinia ◽  
Baishali Kanjilal ◽  
Noahiro Fujinuma ◽  
Amos Mugweru ◽  
Iman Noshadi
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
Co2 Capture ◽  
High Surface ◽  
Scale Up ◽  
Polymer Networks ◽  
High Surface Area ◽  
Excellent Thermal Stability ◽  
Doped Polymers ◽  
Metal Doped

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO2). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO2 capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO2 capture performance, with equilibrium adsorption of 2.3 mmol CO2/g at 0 °C and 1 bar for at a surface area 675.62 m2/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO2 capture and possible subsequent electrochemical conversion.

Impact of transient hypotension on regional cerebral blood flow in humans

2015 ◽  
Vol 129 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Nia C.S. Lewis ◽  
Kurt J. Smith ◽  
Anthony R. Bain ◽  
Kevin W. Wildfong ◽  
Tianne Numan ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Vertebral Artery ◽  
Regional Cerebral Blood Flow ◽  
Internal Carotid ◽  
Regional Cerebral Blood

Diameter reductions in the internal carotid artery (ICA) and vertebral artery (VA) contribute to the decline in brain blood with hypotension. The decline in vertebral blood flow with hypotension was greater when carbon dioxide was low; this was not apparent in the ICA.

The effect of five per cent carbon dioxide on the response of muscle blood flow to isoproterenol in man

1973 ◽  
Vol 14 (1) ◽  
pp. 21-25 ◽  
Author(s):  
C. Xanalatos ◽  
Lindsay MacDonell ◽  
E. Larbi ◽  
I. M. James
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Cent Carbon Dioxide

Determination of Low Blood Flow Limits for Arteriovenous Carbon Dioxide Removal

ASAIO Journal ◽  
1996 ◽  
Vol 42 (5) ◽  
pp. M845-849 ◽  
Author(s):  
ROBERT L. BRUNSTON ◽  
WEIKE TAO ◽  
AKHIL BIDANI ◽  
VICTOR J. CARDENAS ◽  
DANIEL L. TRABER ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Carbon Dioxide Removal

Effect of CO2 and 100% O2 on cerebral blood flow in preterm infants

1980 ◽  
Vol 48 (3) ◽  
pp. 468-472 ◽  
Author(s):  
F. A. Leahy ◽  
D. Cates ◽  
M. MacCallum ◽  
H. Rigatto
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Preterm Infants ◽  
Cerebral Circulation ◽  
Pressure Change ◽  
Venous Occlusion ◽  
Co2 Sensitivity ◽  
Important Regulator ◽  
Carbon Dioxide Pressure

To determine 1) the effect of arterial CO2 change on the neonatal cerebral circulation and 2) whether 100% O2 would produce significant decrease in cerebral blood flow (CBF), we studied 24 preterm infants to explain the late (5 min) hyperventilation observed in them during hyperoxia. Of these, 12 were studied before and during inhalation of 2-3% CO2 and 12 before and during the inhalation of 100% O2. We measured CBF by a modification of the venous occlusion plethysmography technique and found that CBF increased 7.8% per Torr alveolar carbon dioxide pressure change and that it decreased 15% with 100% O2. These findings suggest that 1) CO2 is an important regulator of CBF in the perterm infant, 2) CBF-CO2 sensitivity in these infants may be greater than in adult subjects, 3) 100% O2 reduced CBF significantly, and 4) a decrease in CBF during administration of 100% O2 may be at least partially responsible for the increase in ventilation with hyperoxia.

Effect of Variation in Arterial Carbon Dioxide Levels on Cerebral-Somatic Oxygenation in Children with Cyanotic Congenital Heart Disease

2018 ◽  
pp. 1-6
Keyword(s):  
Carbon Dioxide ◽  
Congenital Heart Disease ◽  
Blood Flow ◽  
Heart Disease ◽  
Infrared Spectroscopy ◽  
Congenital Heart ◽  
Near Infrared ◽  
Cyanotic Congenital Heart Disease ◽  
Anesthesia Induction ◽  
Arterial Blood

Background: Hypocapnia is suggested in decreasing pulmonary vascular resistance in cyanotic congenital heart disease patients undergoing definitive repair. But its effects on cerebral and renal circulation are unclear. Hence the effect of changes in arterial blood carbon dioxide tensions (PaCo2 ) on cerebral (ScO2 %) and renal (SsO2 %) oxygenation indices using Near Infrared spectroscopy (NIRS) is examined. Methods: We did a prospective observational study in sixty-eight children who underwent elective cardiac surgery for various cyanotic congenital heart diseases. PaCo2 , ScO2 % and SsO2 % were obtained before induction of anesthesia, after anesthesia induction at normocapnic or mild hypercapnic ventilation (EtCo2 =40 mmHg) and again at hypocapnic ventilation (EtCo2 =30 mmHg). Regression analysis was done between PaCo2 and NIRS-C/ScO2 % and PaCo2 and NIRS-R/SsO2 % at both EtCo2 40 and 30 mmHg. Repeated measure analysis performed to evaluate the significance of change in NIRS-C and NIRS-R from pre-anesthesia induction to when EtCo2 was 40 and then 30 mmHg post anesthesia induction. Results: With decrease in EtCo2 , PaCo2 (p=0.0001), NIRS-C (p=0.0001) and NIRS-R (p=0.0001) decreased significantly. At EtCo2 of 40 and 30 mmHg, PaCo2 had significant positive correlation with NIRS-C (R2 =0.77, p=0.0001 and R2 =0.92, p=0.0001 respectively) and had insignificant correlation with NIRS-R (R2 =0.03, p=0.12 and R2 =0.008, p=0.46 respectively). Significant changes in NIRS-C {p=0.0001} and NIRS-R {p=0.0001} occurred from pre-induction to when EtCo2 was 40 and then to 30 mmHg. Conclusion: A decrease in NIRS-C and NIRS-R is probably from decreased cerebral and splanchnic blood flow during hypocapnic ventilation, leading to demand supply mismatch. Hypocapnic ventilation in cyanotic children has potential to cause cerebral hypoxia. Abbreviations: CCHD: Cyanotic Congenital Heart Disease; QP: Pulmonary blood flow; Do2 : Oxygen delivery; SpO2 : peripheral pulse oximetry; NIRS: Near Infrared Spectroscopy; NIRS-C/ScO2 %: Regional Cerebral Oxygen saturation; NIRS-R/SsO2 %: Regional Somatic/renal Oxygen saturation; HCT: Hematocrit; ECG: Electrocardiography; CPB: cardiopulmonary bypass; TOF: Tetralogy of fallot; BDG: Bidirectional Glenn Shunt; BT shunt: Blalock Taussig shunt; DORV: Double outlet right ventricle; FiO2 : Inspired oxygen concentration; ABG: Arterial blood gas; PaO2 : Arterial oxygen partial pressure; PaCo2 : Arterial carbon dioxide partial pressure; HR: Heart rate; MAP: Mean Arterial Pressure; CVP: Central Venous Pressure

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