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.

Partial pressure of carbon dioxide in the venous blood of young birds as a predictor of ascites susceptibility in broiler chickens

2010 ◽  
Vol 58 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Mohammad Hassanzadeh ◽  
Mohammad Maddadi ◽  
Sarra Mirzaie ◽  
Keramat Assasie ◽  
Hamid Moayyedian
Keyword(s):  
Carbon Dioxide ◽  
Broiler Chickens ◽  
Venous Blood ◽  
Broiler Breeder ◽  
Fast Growing ◽  
Carbon Dioxide Pressure ◽  
Blood Gas Parameters ◽  
The Relationship ◽  
Slow Growing

In order to investigate the relationship between carbon dioxide tensions in the venous blood of young chickens and ascites susceptibility, one hundred dayold chickens from two pure broiler breeder lines differing in susceptibility to ascites syndrome were obtained and reared at low environmental temperature. Weekly, blood samples were taken for the determination of blood gas parameters and plasma thyroid hormone levels. Dead birds were examined for lesions of ascites daily and all survived birds were autopsied at the end of the trials. In cold conditioning, the cumulative incidence of right ventricular hypertrophy (RVH) and ascites was 78% (39/50) in fast-growing (line A) and 50% (25/50) in slow-growing (line B) chickens, confirming that line A chickens had higher susceptibility to ascites than line B chickens. At 12 days of age, the mean pCO2tension was significantly (P < 0.01) higher in the venous blood of line A than line B chickens. During the experiment, the majority of line A and line B chickens showing RVH and ascites exhibited pCO2tensions equal to, or exceeding 50 mmHg at 12 days of age. Additionally, fast-growing chickens showed significantly lower plasma T3 and T4 concentrations than slow-growing chickens. In conclusion, our data indicate that carbon dioxide pressure in the venous blood of early postnatal broiler chickens could be used as a valuable predictor in the selection of birds susceptible to pulmonary hypertension and ascites. The function of thyroid hormones should also be taken into consideration in further selection procedures for meat-type chickens.

scholarly journals Hemodynamic monitoring with two blood gases: “a tool that does not go out of style”

2020 ◽  
Author(s):  
Jesús Salvador Sánchez-Díaz ◽  
Karla Gabriela Peniche-Moguel ◽  
Gerardo Rivera-Solís ◽  
Enrique Antonio Martínez-Rodríguez ◽  
Luis Del-Carpio-Orantes ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Systematic Review ◽  
Critically Ill ◽  
Hemodynamic Monitoring ◽  
Venous Blood ◽  
Blood Gases ◽  
Review Of The Literature ◽  
Non Invasive ◽  
Arterial Carbon Dioxide ◽  
Carbon Dioxide Pressure

Introduction. Hemodynamic monitoring of a critically ill patient is an indispensable tool both inside and outside intensive care; we currently have invasive, minimally invasive and non-invasive devices; however, no device has been shown to have a positive impact on the patient's evolution; arterial and venous blood gases provide information on the patient's actual microcirculatory and metabolic status and may be a hemodynamic monitoring tool. Objective. To carry out a non-systematic review of the literature of hemodynamic monitoring carried out through the variables obtained in arterial and venous blood gases. Material and methods. A non-systematic review of the literature was performed in the PubMed, OvidSP and ScienceDirect databases with selection of articles from 2000 to 2019. Results. It was found that there are variables obtained in arterial and venous blood gases such as central venous oxygen saturation (SvcO2), venous-to-arterial carbon dioxide pressure (∆pv-aCO2), venous-to-arterial carbon dioxide pressure/arteriovenous oxygen content difference (∆pv-aCO2/∆Ca-vO2) that are related to cellular oxygenation, cardiac output (CO), microcirculatory veno-arterial flow and anaerobic metabolism and allow to assess tissue perfusion status. Conclusion. The variables obtained by arterial and venous blood gases allow for non-invasive, accessible and affordable hemodynamic monitoring that can guide medical decision-making in critically ill patients.

Does Carbon Dioxide Play a Role in Retrolental Fibroplasia?

PEDIATRICS ◽  
1982 ◽  
Vol 70 (3) ◽  
pp. 500-501
Author(s):  
M. L. Wolbarsht ◽  
Gregory S. George ◽  
Jan Kylstra ◽  
M. B. Landers
Keyword(s):  
Carbon Dioxide ◽  
Clinical Research ◽  
Premature Infants ◽  
Oxygen Therapy ◽  
Supplemental Oxygen ◽  
Retrolental Fibroplasia ◽  
High Concentrations ◽  
Supplemental Oxygen Therapy

Gordon et al1 were the first to note the association of retrolental fibroplasia (RLF) with the administration of high concentrations of oxygen to premature infants. Since that time, clinical research has demonostrated that RLF can develop in a variety of circumstances. Typically, this retinopathy arises after the cessation of supplemental oxygen therapy to neonates. Currently, the most widely accepted paradigm proposes that the neovascularization of RLF is the immature vascular system's response to a retina that has become hypoxic after the withdrawal of supplemental oxygen.

MEASUREMENT OF PULMONARY CAPILLARY BLOOD FLOW FOR TRENDING MIXED VENOUS BLOOD OXYGEN SATURATION AND OXYGEN DELIVERY

1998 ◽  
Vol 26 (Supplement) ◽  
pp. 106A
Author(s):  
Marcelo Gama de Abreu ◽  
Stefan Geiger ◽  
Max Ragaller ◽  
Tilo Winkler ◽  
Stefan Rasche ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Capillary Blood ◽  
Mixed Venous Blood ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Pulmonary Capillary Blood Flow ◽  
Pulmonary Capillary ◽  
Pulmonary Capillary Blood ◽  
Mixed Venous

Effect of different pressure breathing patterns on alveolar-arterial gradients in dogs

1963 ◽  
Vol 18 (6) ◽  
pp. 1049-1052 ◽  
Author(s):  
Norman A. Bergman
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Capillary Blood ◽  
Respiratory Cycle ◽  
Positive Pressure ◽  
Pulmonary Capillary Blood Flow ◽  
Pulmonary Capillary ◽  
Mean Pressure ◽  
Pulmonary Capillary Blood ◽  
Intermittent Positive Pressure Breathing

Arterial end-tidal carbon dioxide gradients were measured and alveolar-arterial oxygen gradients were estimated in dogs during intermittent positive pressure ventilation at constant inflating pressure using four curves having differing pressure profiles. The smallest gradients for both oxygen and carbon dioxide occurred when mean pressure during respiratory cycles was high and decreases in mean pressure were consistently associated with increases in both oxygen and carbon dioxide gradients. Profile of the applied pressure curve per se did not influence magnitude of the gradients. It is concluded that during intermittent positive pressure breathing, relative distribution of pulmonary capillary blood flow and inspired gas may vary with mean pressure during the respiratory cycle and is more uniform when mean pressure during the respiratory cycle is high. artificial ventilation; intermittent positive pressure breathing; alveolar-arterial; carbon dioxide gradient; distribution of inspired gas; pulmonary capillary blood flow Submitted on December 13, 1962

STEROID METABOLISM IN THE PERFUSED HUMAN PLACENTA

1978 ◽  
Vol 87 (1) ◽  
pp. 181-191 ◽  
Author(s):  
Alfred S. Wolf ◽  
Klaus A. Musch ◽  
Werner Speidel ◽  
Jürgen R. Strecker ◽  
Christian Lauritzen
Keyword(s):  
Venous Blood ◽  
Placental Lactogen ◽  
Dehydroepiandrosterone Sulphate ◽  
Metabolic Capacity ◽  
Loading Test ◽  
Lower Range ◽  
Group I ◽  
High Concentrations ◽  
Steroid Precursor

ABSTRACT A new model for the perfusion of human term-placentas has been developed for studies on the placental biogenesis of C-18 and C-19 steroids. For viability criteria, the glucose- and oxygen-consumption, regional perfusion control by dye-infusions or scanning after injection of 99Tc-labelled macroparticles, and the histological qualification were chosen. The recycled perfusate was investigated for the steroids oestrone (Oe1), oestradiol-17β (Oe2), oestriol (Oe3), 4-androstene-3,17-dione (A), testosterone (T), and human placental lactogen (HPL) by radioimmunoassay in controls and perfusions with the foetal steroid precursor dehydroepiandrosterone sulphate (DHA-S). In control perfusions, steroid hormones were found in constant ratios (Oe1:Oe2:Oe3:T:A = 30:1.5:100:0.35:1). Following the administration of 10 mg DHA-S for testing the metabolic capacity of the organ, high concentrations of Oe1 (90–720 ng/ml = 250–3970 % as compared to 100% pre-injection values) were found, shortly preceded by a rapid increase of A (66–1000 ng/ml = 100–16 000 %). A typical surge of T (5.3–147 ng/ml = 265–4640 %) preceded the normally slower increment of Oe2 (22–220 ng/ml = 1570–4330 %). The concentrations of Oe3 and HPL remained nearly unchanged. From different steroid patterns after DHA-S-load, two distinct responses of term-placentas could be differentiated: Group I (n=12) showed high concentrations of Oe1 (3200 ± 940 %), a small increase of T (1020 ± 500%), as well as low and delayed values of Oe2 (1660 ± 450%). In Group II (n = 5), values were high for T (3160 ± 1020%) and Oe2 (3300 ± 1110%), whereas Oe1 was found in a lower range (508 ± 302%). In contrast to in vivo findings in maternal venous blood after DHS-S injection to the mother, oestrone was found in perfusions as the main oestrogen fraction from DHA-S. Thus, the analysis of such metabolic differences might be of help in the interpretation of complex results from the DHA-S-loading test.

Sign in / Sign up

Export Citation Format

Share Document