PULMONARY FUNCTION, DEDUCED FROM URINARY NITROGEN TENSIONS

PEDIATRICS ◽  
1967 ◽  
Vol 40 (6) ◽  
pp. 937-938
Author(s):  
M. E. A.
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Pulmonary Function ◽  
Partial Pressure ◽  
Urine Sample ◽  
Pulmonary Blood Flow ◽  
Lung Perfusion ◽  
Alveolar Ventilation ◽  
Arterial Oxygen ◽  
Urinary Nitrogen

THE elegant studies reported by Led-better, Homma, and Farhi in this issue are entitled `'Readjustment in Distribution of Alveolar Ventilation and Lung Perfusion in the Newborn." It must come as a great surprise to the reader to discover that the only measurement actually made was the partial pressure of nitrogen in the infants' urine. How could one conclude that there were significant imbalances between the distribution of alveolar ventilation and pulmonary blood flow (VA/Q) in the first days of life in normal infants from a urine sample? It is all the more astounding in the light of previous (and seemingly more direct) studies of alveolar-arterial oxygen and carbon dioxide differences which led others to consider the differences largely explained by anatomical right-to-left shunts.

Hemodilution during Venous Gas Embolization Improves Gas Exchange, without Altering V̇A/Q̇ or Pulmonary Blood Flow Distributions 

1999 ◽  
Vol 91 (6) ◽  
pp. 1861-1861 ◽  
Author(s):  
Steven Deem ◽  
Steven McKinney ◽  
Nayak L. Polissar ◽  
Richard G. Hedges ◽  
Erik R. Swenson
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Lung Injury ◽  
Partial Pressure ◽  
Pulmonary Blood Flow ◽  
Flow Distribution ◽  
Arterial Oxygen ◽  
Control Group ◽  
Blood Flow Distribution ◽  
Over Time

Background Isovolemic anemia results in improved gas exchange in rabbits with normal lungs but in relatively poorer gas exchange in rabbits with whole-lung atelectasis. In the current study, the authors characterized the effects of hemodilution on gas exchange in a distinct model of diffuse lung injury: venous gas embolization. Methods Twelve anesthetized rabbits were mechanically ventilated at a fixed rate and volume. Gas embolization was induced by continuous infusion of nitrogen via an internal jugular venous catheter. Serial hemodilution was performed in six rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; six rabbits were followed as controls over time. Measurements included hemodynamic parameters and blood gases, ventilation-perfusion (V(A)/Q) distribution (multiple inert gas elimination technique), pulmonary blood flow distribution (fluorescent microspheres), and expired nitric oxide (NO; chemoluminescence). Results Venous gas embolization resulted in a decrease in partial pressure of arterial oxygen (PaO2) and an increase in partial pressure of arterial carbon dioxide (PaCO2), with markedly abnormal overall V(A)/Q distribution and a predominance of high V(A)/Q areas. Pulmonary blood flow distribution was markedly left-skewed, with low-flow areas predominating. Hematocrit decreased from 30+/-1% to 11+/-1% (mean +/- SE) with hemodilution. The alveolar-arterial PO2 (A-aPO2) difference decreased from 375+/-61 mmHg at 30% hematocrit to 218+/-12.8 mmHg at 15% hematocrit, but increased again (301+/-33 mmHg) at 11% hematocrit. In contrast, the A-aPO2 difference increased over time in the control group (P < 0.05 between groups over time). Changes in PaO2 in both groups could be explained in large part by variations in intrapulmonary shunt and mixed venous oxygen saturation (SvO2); however, the improvement in gas exchange with hemodilution was not fully explained by significant changes in V(A)/Q or pulmonary blood flow distributions, as quantitated by the coefficient of variation (CV), fractal dimension, and spatial correlation of blood flow. Expired NO increased with with gas embolization but did not change significantly with time or hemodilution. Conclusions Isovolemic hemodilution results in improved oxygen exchange in rabbits with lung injury induced by gas embolization. The mechanism for this improvement is not clear.

VENTILATION-PERFUSION RELATIONSHIPS IN CHILDREN WITH HEART DISEASE AND DIMINISHED PULMONARY BLOOD FLOW

PEDIATRICS ◽  
1968 ◽  
Vol 42 (5) ◽  
pp. 778-785
Author(s):  
Martin H. Lees ◽  
Richard H. Burnell ◽  
Clarence L. Morgan ◽  
Benjamin B. Ross
Keyword(s):  
Blood Flow ◽  
Heart Disease ◽  
Pulmonary Artery ◽  
Pulmonary Function ◽  
Pulmonary Artery Pressure ◽  
Pulmonary Blood Flow ◽  
Alveolar Ventilation ◽  
Uneven Distribution ◽  
Artery Pressure ◽  
Major Abnormality

Pulmonary function of infants and children with diminished pulmonary blood flow was studied by measurement of alveolar ventilation and alveolar-arterial gas tension differences of O2, CO2, and N2. The increased ventilation of these subjects was found to be effective in CO2 elimination (arterial CO2 tension, 31 mm Hg), but there was evidence of considerable unevenness of distribution of ventilation/perfusion ratios (VAQ). A measure of the degree of VA/Q unevenness was obtained by use of the urine-alveolar nitrogen tension difference. It is likely, under the prevailing conditions of hyperventilation and hypoperfusion, that maldistribution of perfusion is the major abnormality. Uneven distribution of perfusion is most probably due to the effects of gravity enhanced by low pulmonary artery pressure and blood flow—an exaggenation of the normal physiologic relative overperfusion of the lower-most parts of the lung.

scholarly journals Bidirectional Ductal Shunting and Preductal to Postductal Oxygenation Gradient in Persistent Pulmonary Hypertension of the Newborn

Children ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 137
Author(s):  
Amy Lesneski ◽  
Morgan Hardie ◽  
William Ferrier ◽  
Satyan Lakshminrusimha ◽  
Payam Vali
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Arterial Oxygen Tension ◽  
Persistent Pulmonary Hypertension ◽  
Arterial Oxygen ◽  
Meconium Aspiration ◽  
Arterial Blood Gas ◽  
Arterial Blood

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN). Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow. Results: Meconium aspiration resulted in hypoxemia. The bidirectional ductal shunt had a lower postductal partial arterial oxygen tension ([PaO2] with lower PaO2/FiO2 ratio—97 ± 36 vs. 130 ± 65 mmHg) and left pulmonary flow (81 ± 52 vs. 133 ± 82 mL/kg/min). However, 56% of the samples with a bidirectional shunt had a pre- and postductal saturation gradient of < 3%. Conclusions: The presence of a bidirectional ductal shunt is associated with hypoxemia and low pulmonary blood flow. The absence of a pre- and postductal saturation difference is frequently observed with bidirectional right-to-left shunting through the PDA, and does not exclude a diagnosis of PPHN in this model.

Effect of acceleration on the distribution of pulmonary blood flow

1965 ◽  
Vol 20 (6) ◽  
pp. 1129-1132 ◽  
Author(s):  
A. C. Bryan ◽  
W. D. Macnamara ◽  
J. Simpson ◽  
H. N. Wagner
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Pulmonary Blood Flow ◽  
Lung Perfusion ◽  
Centrifugal Acceleration ◽  
Vascular Bed ◽  
Macroaggregated Albumin ◽  
Iodine 131 ◽  
Pulmonary Vascular Bed

The distribution of pulmonary blood flow has been measured during increased positive (+Gz) acceleration. Macroaggregated albumin labeled with iodine 131 was injected intravenously during centrifugal acceleration, by the method described by Wagner and co-workers. The particles embolize the pulmonary vascular bed in proportion to flow and can be subsequently detected by scintillation scanning of the lung. One study was done in one subject in one of the five following conditions: supine, seated, +2 Gz, +3 Gz, and +4 Gz. The results show a progressively smaller reduction in upper zone perfusion with increasing acceleration agreeing with hydrostatic principles. Flow increased in the base up to +2 Gz but thereafter becomes fixed, suggesting that the vessels were then maximally dilated. The gas exchange consequences of these changes of perfusion are discussed indicating that there must also be ventilatory changes. lung; perfusion; iodine 131; acceleration Submitted on January 18, 1965

Physiological alterations in increased pulmonary blood flow with and without pulmonary hypertension

1961 ◽  
Vol 16 (2) ◽  
pp. 305-308 ◽  
Author(s):  
Lois T. Ellison ◽  
David P. Hall ◽  
Thomas Yeh ◽  
H. Mobarhan ◽  
Joseph Rossi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Artery ◽  
Pulmonary Function ◽  
Pulmonary Artery Pressure ◽  
Pulmonary Blood Flow ◽  
Pulmonary Artery Hypertension ◽  
Systolic Pulmonary Artery Pressure ◽  
Venous Admixture ◽  
Artery Pressure ◽  
Physiological Alterations

Alterations in pulmonary function and in hemodynamics were studied in dogs with high pulmonary blood flow resulting from systemic pulmonary artery shunts. In order to facilitate elevation in pulmonary artery pressure, the vascular bed was reduced in some cases by obstructing branches of the pulmonary artery with Teflon clips or by lobectomy. Results in 30 control dogs and in 30 animals that survived 5–36 months (average 16) following creation of shunts indicated that pulmonary function was not significantly altered by increased pulmonary blood flow until pulmonary artery hypertension developed. When systolic pulmonary artery pressure exceeded 40 mm Hg, there was a decrease in arterial Po2, an increase in venous admixture percentage of cardiac output, and an increase in the A-a O2 difference during three levels of O2 breathing, indicating both abnormal venous admixture and abnormal diffusion. Possible explanations for these findings are presented. Evidence in one dog suggests that these alterations are reversible. Submitted on August 10, 1960

Sign in / Sign up

Export Citation Format

Share Document