scholarly journals Variations in alveolar carbon dioxide pressure in relation to meals1

1921 ◽  
Vol 54 (5-6) ◽  
pp. 342-348 ◽  
Author(s):  
E. C. Dodds
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Pressure

Exercise end-tidal carbon dioxide pressure: a new prognostic marker after acute myocardial infarction?

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
J Ferreira ◽  
P Rio ◽  
A Castelo ◽  
I Cardoso ◽  
S Silva ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Carbon Dioxide ◽  
Acute Myocardial Infarction ◽  
Prognostic Marker ◽  
Systolic Function ◽  
Prognostic Role ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Pressure ◽  
End Tidal ◽  
Maximal Effort

Abstract Funding Acknowledgements Type of funding sources: None. Background Although several cardiopulmonary exercise testing (CPET) parameters have already proved to predict prognosis, there is increasing interest in finding variables that do not require maximal effort. End-tidal carbon dioxide pressure (PETCO2), an indirect indicator of cardiac output, is one of such variables. Studies in heart failure populations already suggest its role as a prognostic factor. However, data concerning other populations are still scarce. Purpose To assess the association between exercise PETCO2, cardiac biomarkers and systolic function following acute myocardial infarction (AMI) and to evaluate its potential prognostic role in this population. Methods A retrospective single-centre analysis was conducted including patients who underwent symptom-limited CPET early after AMI. We assessed PETCO2 at baseline (PETCO2-B), at anaerobic threshold (PETCO2-AT) and at peak exercise and calculated the difference between PETCO2-AT and PETCO2-B (PETCO2-difference). We analysed their association with B-natriuretic peptide (BNP), maximal troponin after AMI as well as with left ventricular ejection fraction (LVEF) 1 year after. Results We included 40 patients with a mean age of 56 years (87.5% male), assessed with CPET a median of 3 months after AMI (80% of which were ST-elevation myocardial infarctions). Average respiratory exchange ratio was 1,1 with 48% of patients not reaching maximal effort. Mean PETCO2-AT was 37mmHg, with a mean increase from baseline of 6mmHg (PETCO2-difference). There was a significant positive correlation between all the PETCO2 variables measured and BNP values at time of AMI and on follow-up (best correlation for PETCO2-AT with BNP at AMI hospitalization, r = 0.608, p < 0.001). Maximal troponin was not correlated with PETCO2. Both PETCO2-AT and PETCO2-difference were significantly and positively correlated with LVEF 1-year post-AMI (r = 0.421, p = 0.040 and r = 0.511, p = 0.011, respectively). Conclusion PETCO2-AT and PETCO2-difference are both correlated with BNP, an established prognostic marker, and with medium-term systolic function after AMI, suggesting their potential prognostic role in this population. Further studies with larger samples are required to confirm the results of this pilot study and assess PETCO2 as a definite predictor of prognosis after AMI.

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.

Isothermal exfoliation of graphene oxide by a new carbon dioxide pressure swing method

Carbon ◽  
2014 ◽  
Vol 68 ◽  
pp. 112-117 ◽  
Author(s):  
Seul-Yi Lee ◽  
Soo-Jin Park
Keyword(s):  
Carbon Dioxide ◽  
Graphene Oxide ◽  
Carbon Dioxide Pressure ◽  
Pressure Swing

scholarly journals Accuracy of Postoperative End-tidal Pco2Measurements with Mainstream and Sidestream Capnography in Non-obese Patients and in Obese Patients with and without Obstructive Sleep Apnea

2009 ◽  
Vol 111 (3) ◽  
pp. 609-615 ◽  
Author(s):  
Yusuke Kasuya ◽  
Ozan Akça ◽  
Daniel I. Sessler ◽  
Makoto Ozaki ◽  
Ryu Komatsu
Keyword(s):  
Carbon Dioxide ◽  
Body Mass Index ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Nasal Cannula ◽  
Obese Patients ◽  
Obstructive Sleep ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Pressure ◽  
End Tidal

Background Obtaining accurate end-tidal carbon dioxide pressure measurements via nasal cannula poses difficulties in postanesthesia patients who are mouth breathers, including those who are obese and those with obstructive sleep apnea (OSA); a nasal cannula with an oral guide may improve measurement accuracy in these patients. The authors evaluated the accuracy of a mainstream capnometer with an oral guide nasal cannula and a sidestream capnometer with a nasal cannula that did or did not incorporate an oral guide in spontaneously breathing non-obese patients and obese patients with and without OSA during recovery from general anesthesia. Methods The study enrolled 20 non-obese patients (body mass index less than 30 kg/m) without OSA, 20 obese patients (body mass index greater than 35 kg/m) without OSA, and 20 obese patients with OSA. End-tidal carbon dioxide pressure was measured by using three capnometer/cannula combinations (oxygen at 4 l/min): (1) a mainstream capnometer with oral guide nasal cannula, (2) a sidestream capnometer with a nasal cannula that included an oral guide, and (3) a sidestream capnometer with a standard nasal cannula. Arterial carbon dioxide partial pressure was determined simultaneously. The major outcome was the arterial-to-end-tidal partial pressure difference with each combination. Results In non-obese patients, arterial-to-end-tidal pressure difference was 3.0 +/- 2.6 (mean +/- SD) mmHg with the mainstream capnometer, 4.9 +/- 2.3 mmHg with the sidestream capnometer and oral guide cannula, and 7.1 +/- 3.5 mmHg with the sidestream capnometer and a standard cannula (P < 0.05). In obese non-OSA patients, it was 3.9 +/- 2.6 mmHg, 6.4 +/- 3.1 mmHg, and 8.1 +/- 5.0 mmHg, respectively (P < 0.05). In obese OSA patients, it was 4.0 +/- 3.1 mmHg, 6.3 +/- 3.2 mmHg, and 8.3 +/- 4.6 mmHg, respectively (P < 0.05). Conclusions Mainstream capnometry performed best, and an oral guide improved the performance of sidestream capnometry. Accuracy in non-obese and obese patients, with and without OSA, was similar.

PHYSIOLOGICAL CONSIDERATION OF RESPIRATORY DISEASE

PEDIATRICS ◽  
1952 ◽  
Vol 9 (2) ◽  
pp. 233-236
Author(s):  
JULIUS H. COMROE
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Therapy ◽  
Venous Blood ◽  
Respiratory Center ◽  
Normal Lung ◽  
Regulation Of Respiration ◽  
Pulmonary Capillary Blood Flow ◽  
Pulmonary Capillary Blood ◽  
Carbon Dioxide Pressure ◽  
High Concentrations

A. Physiologic Factors Concerned in the Regulation of Respiration Physiologists now agree that there is a medullary respiratory center which has intrinsic rhythmicity. Nevertheless this center can be influenced profoundly by many chemical and nervous factors. One of the most important of these is carbon dioxide. Under ordinary conditions the medullary center is exquisitely sensitive to changes in carbon dioxide pressure. When the respiratory center is depressed (by deep anesthesia, large doses of morphine or barbiturates, trauma, cerebral edema, increased intra-cranial pressure, severe anoxia or by high concentrations of carbon dioxide itself) it is no longer responsive to carbon dioxide though it may still permit reflex activity and continuation of respiration. Anoxemia may also stimulate respiration; this occurs through reflexes originating in chemoreceptors of the carotid and aortic bodies. It appears certain that these chemoreceptors are functioning in the normal full-term newborn though they may not be functioning or functioning properly in prematures. When these chemoreceptors are in operation, anoxia will stimulate respiration and oxygen therapy will abolish such hyperpnea. When the chemoreceptors are not in action, one would expect no reflex effects from either oxygen or anoxia; oxygen therapy, however, might relieve cerebral ischemia and permit respiration to improve. B. Physiologic Methods for Evaluating Respiratory and Pulmonary Function The function of the lungs is primarily to oxygenate the venous blood and to remove excess carbon dioxide from it. To accomplish this, there must be normal respiratory volumes, normal lung volumes and aerating surface, even distribution of the inspired gas to the alveoli, unimpaired diffusion across the alveolar capillary membrane, and uniform distribution of pulmonary capillary blood flow to the functioning alveoli.

scholarly journals Extraction of Galphimines from Galphimia glauca with Supercritical Carbon Dioxide

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 477 ◽  
Author(s):  
Francisco Javier Verónico Sánchez ◽  
Octavio Elizalde Solis ◽  
Alejandro Zamilpa ◽  
Ricardo García Morales ◽  
Ma. Dolores Pérez García ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Carbon Dioxide ◽  
Particle Diameter ◽  
Anxiolytic Effect ◽  
Extraction Techniques ◽  
Pharmaceutical Applications ◽  
Rate Effects ◽  
Adequate Quality ◽  
Carbon Dioxide Pressure ◽  
Hplc Analyses

The anti-depressive and anxiolytic effect of galphimine B (isolated from Galphimia glauca) has been demonstrated by researchers. Therefore, it is necessary to explore extraction techniques that produce materials with adequate quality for pharmaceutical applications. In this work, supercritical extractions of galphimines from Galphimia glauca were performed in the presence of carbon dioxide. Pressure, temperature, particle diameter, and flow rate effects were examined to explore the conditions with the highest yield and the concentration profile of galphimines in the studied interval. The identification of the nor-seco triterpenoids and galphimine B and E was carried out by HPLC analyses. The mathematical modeling of the extraction curves was attained by the approaches proposed by Sovová and Papamichail et al. According to results, the highest yield 2.22% was obtained at 323.15 K, 326 μm, 3 L/min, and 33.75 MPa. Meanwhile, the content of galphimine B in the extract was, on average, 19.5 mg·g−1.

Improved carbon dioxide pressure regulator

1960 ◽  
Vol 4 (1) ◽  
pp. 97-99 ◽  
Author(s):  
Carmine Dipietro ◽  
Warren A. Sassaman ◽  
Charles Merritt
Keyword(s):  
Carbon Dioxide ◽  
Pressure Regulator ◽  
Carbon Dioxide Pressure
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