Single-Breath Breath Holding Measurement of Pulmonary Blood Flow: Comparison to Direct Fick Cardiac Output

1986 ◽  
Vol 71 (s15) ◽  
pp. 36P-36P ◽  
Author(s):  
A.H. Kendrick ◽  
A. Rozkovec ◽  
M. Papouchado ◽  
J. West ◽  
J.E. Bees ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Blood Flow ◽  
Breath Holding ◽  
Single Breath

Single-breath breath-holding estimate of pulmonary blood flow in man: comparison with direct Fick cardiac output

1989 ◽  
Vol 76 (6) ◽  
pp. 673-676 ◽  
Author(s):  
A. H. Kendrick ◽  
A. Rozkovec ◽  
M. Papouchado ◽  
J. West ◽  
G. Laszlo
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Blood Flow ◽  
Hold Time ◽  
Normal Subjects ◽  
Breath Holding ◽  
Breath Hold ◽  
Single Breath ◽  
Significant Difference ◽  
Cardiac Disorders

1. Resting pulmonary blood flow (Q.), using the uptake of the soluble inert gas Freon-22 and an indirect estimate of lung tissue volume, has been estimated during breath-holding (Q.c) and compared with direct Fick cardiac output (Q.f) in 16 patients with various cardiac disorders. 2. The effect of breath-hold time was investigated by comparing Q.c estimated using 6 and 10 s of breath-holding in 17 patients. Repeatability was assessed by duplicate measurements of Q.c in the patients and in six normal subjects. 3. Q.c tended to overestimate Q.f, the bias and error being 0.09 l/min and 0.59, respectively. The coefficient of repeatability for Q.c in the patients was 0.75 l/min and in the normal subjects was 0.66 1/min. For Q.f it was 0.72 l/min. There was no significant difference in Q.c measured at the two breath-hold times. 4. The technique is simple to perform, and provides a rapid estimate of Q., monitoring acute and chronic changes in cardiac output in normal subjects and patients with cardiac disease.

An analysis of estimation of pulmonary blood flow by the single-breath method

1986 ◽  
Vol 61 (1) ◽  
pp. 198-209 ◽  
Author(s):  
R. Srinivasan
Keyword(s):  
Blood Flow ◽  
Lung Tissue ◽  
Measurement Errors ◽  
Pulmonary Blood Flow ◽  
Breath Holding ◽  
Co2 Absorption ◽  
Rigorous Approach ◽  
Single Breath ◽  
Insight Into ◽  
Single Breath Method

The single-breath method of determining pulmonary blood flow is a simple technique involving no inert gas or special maneuvers such as rebreathing or breath holding. The use of this elegant technique has been limited, however, largely because of questions regarding its accuracy. Previous analyses of the method have indicated that large errors in the estimated blood flow could result if data reduction is not handled carefully. In addition, an uncertain amount of error is introduced, if the CO2 retained by the lung tissue while measurements are being made is not taken into account in the calculations. This paper presents a rigorous approach for estimating the pulmonary blood flow by the single-breath method, which would minimize considerably the effects of measurement errors and would also allow for possible CO2 absorption by the lung tissue. It is based on the exact solution of the underlying equations that describe the dynamics of gas exchange in the lung. The analytic solution provides insight into the difficulties involved in extracting the desired information from the experimental data.

Assessment of cardiorespiratory function using oscillating inert gas forcing signals

1994 ◽  
Vol 76 (5) ◽  
pp. 2130-2139 ◽  
Author(s):  
E. M. Williams ◽  
J. B. Aspel ◽  
S. M. Burrough ◽  
W. A. Ryder ◽  
M. C. Sainsbury ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Dead Space ◽  
Confidence Limit ◽  
Pulmonary Blood Flow ◽  
Mean Difference ◽  
Alveolar Volume ◽  
Single Breath ◽  
Cardiorespiratory Function ◽  
Airway Dead Space

A theoretical model (Hahn et al. J. Appl. Physiol. 75: 1863–1876, 1993) predicts that the amplitudes of the argon and nitrous oxide inspired, end-expired, and mixed expired sinusoids at forcing periods in the range of 2–3 min (frequency 0.3–0.5 min-1) can be used directly to measure airway dead space, lung alveolar volume, and pulmonary blood flow. We tested the ability of this procedure to measure these parameters continuously by feeding monosinusoidal argon and nitrous oxide forcing signals (6 +/- 4% vol/vol) into the inspired airstream of nine anesthetized ventilated dogs. Close agreement was found between single-breath and sinusoid airway dead space measurements (mean difference 15 +/- 6%, 95% confidence limit), N2 washout and sinusoid alveolar volume (mean difference 4 +/- 6%, 95% confidence limit), and thermal dilution and sinusoid pulmonary blood flow (mean difference 12 +/- 11%, 95% confidence limit). The application of 1 kPa positive end-expiratory pressure increased airway dead space by 12% and alveolar volume from 0.8 to 1.1 liters but did not alter pulmonary blood flow, as measured by both the sinusoid and comparator techniques. Our findings show that the noninvasive sinusoid technique can be used to measure cardiorespiratory lung function and allows changes in function to be resolved in 2 min.

Effects of ouabain on cardiac output and pulmonary blood flow in dogs

1972 ◽  
Vol 84 (3) ◽  
pp. 371-376 ◽  
Author(s):  
Elmer Treat ◽  
Harvey Ulano ◽  
Marc Pfeffer ◽  
Walter Massion ◽  
Linda L. Shanbour ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Blood Flow

EVALUATION OF IMPEDANCE CARDIAC OUTPUT IN CHILDREN

PEDIATRICS ◽  
1971 ◽  
Vol 47 (5) ◽  
pp. 870-879
Author(s):  
Zuhdi Lababidi ◽  
D. A. Ehmke ◽  
Robert E. Durnin ◽  
Paul E. Leaverton ◽  
Ronald M. Lauer
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Standard Deviation ◽  
Pulmonary Blood Flow ◽  
Impedance Measurement ◽  
Aortic Insufficiency ◽  
Mean Difference ◽  
Dye Dilution ◽  
Impedance Cardiograph ◽  
Indicator Dye

In 20 children without shunts or valvular insufficiency, duplicate dye dilution and impedance cardiac outputs (ICO) were carried out. The duplicate dye dilutions had a standard deviation 0.259 L/min/m2, while duplicate ICO had a standard deviation 0.192 L/min/m2 (F = 1.82, p < 0.05). Of 53 sequential estimates, cardiac outputs measured by both indicator dye dilution and ICO had a 5.5% mean difference. In 21 subjects with left to right shunts, the ICO related well with pulmonary blood flow (r = 0.92) rather than systemic flow (r = 0.21). In 13 subjects with aortic insufficiency, sequential Fick and ICO had a 50% mean difference; the impedance measurement was found to be higher in every case. These data indicate that the impedance cardiograph can provide a noninvasive measure of cardiac output when there are no shunts or valvular insufficiencies. In subjects with left to right shunts the impedance cardiograph provides a measure of the pulmonary blood flow. When aortic insufficiency exists the impedance cardiograph is distorted such that it is consistently higher than Fick cardiac output.

The underwater environment: cardiopulmonary, thermal, and energetic demands

2009 ◽  
Vol 106 (1) ◽  
pp. 276-283 ◽  
Author(s):  
D. R. Pendergast ◽  
C. E. G. Lundgren
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Time Dependent ◽  
Breath Holding ◽  
Peripheral Blood Flow ◽  
Short Term ◽  
Underwater Environment ◽  
Maximal Cardiac Output

Water covers over 75% of the earth, has a wide variety of depths and temperatures, and holds a great deal of the earth's resources. The challenges of the underwater environment are underappreciated and more short term compared with those of space travel. Immersion in water alters the cardio-endocrine-renal axis as there is an immediate translocation of blood to the heart and a slower autotransfusion of fluid from the cells to the vascular compartment. Both of these changes result in an increase in stroke volume and cardiac output. The stretch of the atrium and transient increase in blood pressure cause both endocrine and autonomic changes, which in the short term return plasma volume to control levels and decrease total peripheral resistance and thus regulate blood pressure. The reduced sympathetic nerve activity has effects on arteriolar resistance, resulting in hyperperfusion of some tissues, which for specific tissues is time dependent. The increased central blood volume results in increased pulmonary artery pressure and a decline in vital capacity. The effect of increased hydrostatic pressure due to the depth of submersion does not affect stroke volume; however, a bradycardia results in decreased cardiac output, which is further reduced during breath holding. Hydrostatic compression, however, leads to elastic loading of the chest wall and negative pressure breathing. The depth-dependent increased work of breathing leads to augmented respiratory muscle blood flow. The blood flow is increased to all lung zones with some improvement in the ventilation-perfusion relationship. The cardiac-renal responses are time dependent; however, the increased stroke volume and cardiac output are, during head-out immersion, sustained for at least hours. Changes in water temperature do not affect resting cardiac output; however, maximal cardiac output is reduced, as is peripheral blood flow, which results in reduced maximal exercise performance. In the cold, maximal cardiac output is reduced and skin and muscle are vasoconstricted, resulting in a further reduction in exercise capacity.

scholarly journals Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect

2007 ◽  
Vol 103 (1) ◽  
pp. 240-248 ◽  
Author(s):  
Susan R. Hopkins ◽  
A. Cortney Henderson ◽  
David L. Levin ◽  
Kei Yamada ◽  
Tatsuya Arai ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Breath Holding ◽  
Proton Density ◽  
Dependent Lung ◽  
Lung Density ◽  
Regional Lung ◽  
Vertical Height ◽  
Vertical Gradients

In vivo radioactive tracer and microsphere studies have differing conclusions as to the magnitude of the gravitational effect on the distribution of pulmonary blood flow. We hypothesized that some of the apparent vertical perfusion gradient in vivo is due to compression of dependent lung increasing local lung density and therefore perfusion/volume. To test this, six normal subjects underwent functional magnetic resonance imaging with arterial spin labeling during breath holding at functional residual capacity, and perfusion quantified in nonoverlapping 15 mm sagittal slices covering most of the right lung. Lung proton density was measured in the same slices using a short echo 2D-Fast Low-Angle SHot (FLASH) sequence. Mean perfusion was 1.7 ± 0.6 ml·min−1·cm−3 and was related to vertical height above the dependent lung (slope = −3%/cm, P < 0.0001). Lung density averaged 0.34 ± 0.08 g/cm3 and was also related to vertical height (slope = −4.9%/cm, P < 0.0001). By contrast, when perfusion was normalized for regional lung density, the slope of the height-perfusion relationship was not significantly different from zero ( P = 0.2). This suggests that in vivo variations in regional lung density affect the interpretation of vertical gradients in pulmonary blood flow and is consistent with a simple conceptual model: the lung behaves like a Slinky (Slinky is a registered trademark of Poof-Slinky Incorporated), a deformable spring distorting under its own weight. The greater density of lung tissue in the dependent regions of the lung is analogous to a greater number of coils in the dependent portion of the vertically oriented spring. This implies that measurements of perfusion in vivo will be influenced by density distributions and will differ from excised lungs where density gradients are reduced by processing.

Sign in / Sign up

Export Citation Format

Share Document