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.

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

Measurement of temporal changes in DLSBCO-3EQ from small alveolar samples in normal subjects

1994 ◽  
Vol 76 (4) ◽  
pp. 1494-1501 ◽  
Author(s):  
G. R. Soparkar ◽  
J. T. Mink ◽  
B. L. Graham ◽  
D. J. Cotton
Keyword(s):  
Hold Time ◽  
Normal Subjects ◽  
Gas Diffusion ◽  
Phase Iii ◽  
Mixing Efficiency ◽  
Breath Holding ◽  
Breath Hold ◽  
Inspiratory Capacity ◽  
Ventilation Inhomogeneity ◽  
Single Breath

The dynamic changes in CO concentration [CO] during a single breath could be influenced by topographic inhomogeneity in the lung or by peripheral inhomogeneity due to a gas mixing resistance in the gas phase of the lung or to serial gradients in gas diffusion. Ten healthy subjects performed single-breath maneuvers by slowly inhaling test gas from functional residual capacity to one-half inspiratory capacity and slowly exhaling to residual volume with target breath-hold times of 0, 1.5, 3, 6, and 9 s. We calculated the three-equation single-breath diffusing capacity of the lung for CO (DLSBCO-3EQ) from the mean [CO] in both the entire alveolar gas sample and in four successive equal alveolar gas samples. DLSBCO-3EQ from the entire alveolar gas sample was independent of breath-hold time. However, with 0 s of breath holding, from early alveolar gas samples DLSBCO-3EQ was reduced and from late alveolar gas samples it was increased. With increasing breath-hold time, DLSBCO-3EQ from the earliest alveolar gas sample rapidly increased, whereas from the last alveolar gas sample it rapidly decreased such that all values from the small alveolar gas samples approached DLSBCO-3EQ from the entire alveolar sample. These changes correlated with ventilation inhomogeneity, as measured by the phase III He concentration slope and the mixing efficiency, and were larger for maneuvers with inspired volumes to one-half inspiratory capacity vs. total lung capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ventilation inhomogeneity on "intrabreath" measurements of diffusing capacity in normal subjects

1993 ◽  
Vol 75 (2) ◽  
pp. 927-932 ◽  
Author(s):  
D. J. Cotton ◽  
M. B. Prabhu ◽  
J. T. Mink ◽  
B. L. Graham
Keyword(s):  
Lung Volume ◽  
Hold Time ◽  
Normal Subjects ◽  
Phase Iii ◽  
Breath Hold ◽  
Diffusing Capacity ◽  
Ventilation Inhomogeneity ◽  
Single Breath ◽  
The Mean ◽  
And Diffusion

In normal seated subjects we increased single-breath ventilation inhomogeneity by changing both the preinspiratory lung volume and breath-hold time and examined the ensuing effects on two different techniques of measuring the diffusing capacity of the lung for carbon monoxide (DLCO). We measured the mean single-breath DLCO using the three-equation method (DLCOSB-3EQ) and also measured DLCO over discrete intervals during exhalation by the "intrabreath" method (DLCOexhaled). We assessed the distribution of ventilation using the normalized phase III slope for helium (SN). DLCOSB-3EQ was unaffected by preinspiratory lung volume and breath-hold time. DLCOexhaled increased with increasing preinspiratory lung volume and decreased with increasing breath-hold time. These changes correlated with the simultaneously observed changes in ventilation inhomogeneity as measured by SN (P < 0.01). We conclude that measurements of DLCOexhaled do not accurately reflect the mean DLCO. Intrabreath methods of measuring DLCO are based on the slope of the exhaled CO concentration curve, which is affected by both ventilation and diffusion inhomogeneities. Although DLCOexhaled may theoretically provide information about the distribution of CO uptake, the concomitant effects of ventilation nonuniformity on DLCOexhaled may mimic or mask the effects of diffusion nonuniformity.

Effects of ventilation inhomogeneity on DLcoSB-3EQ in normal subjects

1992 ◽  
Vol 73 (6) ◽  
pp. 2623-2630 ◽  
Author(s):  
D. J. Cotton ◽  
M. B. Prabhu ◽  
J. T. Mink ◽  
B. L. Graham
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Hold Time ◽  
Airflow Obstruction ◽  
Normal Subjects ◽  
Phase Iii ◽  
Mixing Efficiency ◽  
Breath Hold ◽  
Ventilation Inhomogeneity ◽  
Single Breath

In patients with airflow obstruction, we found that ventilation inhomogeneity during vital capacity single-breath maneuvers was associated with decreases in the three-equation single-breath CO diffusing capacity of the lung (DLcoSB-3EQ) when breath-hold time (tBH) decreased. We postulated that this was due to a significant resistance to diffusive gas mixing within the gas phase of the lung. In this study, we hypothesized that this phenomenon might also occur in normal subjects if the breathing cycle were altered from traditional vital capacity maneuvers to those that increase ventilation inhomogeneity. In 10 normal subjects, we examined the tBH dependence of both DLcoSB-3EQ and the distribution of ventilation, measured by the mixing efficiency and the normalized phase III slope for helium. Preinspiratory lung volume (V0) was increased by keeping the maximum end-inspiratory lung volume (Vmax) constant or by increasing V0 and Vmax. When V0 increased while Vmax was kept constant, we found that the tBH-independent and the tBH-dependent components of ventilation inhomogeneity increased, but DLcoSB-3EQ was independent of V0 and tBH. Increasing V0 and Vmax did not change ventilation inhomogeneity at a tBH of 0 s, but the tBH-dependent component decreased. DLcoSB-3EQ, although independent of tBH, increased slightly with increases in Vmax. We conclude that in normal subjects increases in ventilation inhomogeneity with increases in V0 do not result in DLcoSB-3EQ becoming tBH dependent.

Evaluation using dogs of a method for estimating cardiac output from a single breath

1981 ◽  
Vol 50 (1) ◽  
pp. 200-202 ◽  
Author(s):  
M. M. Mohammed ◽  
L. M. Wood ◽  
R. Hainsworth
Keyword(s):  
Cardiac Output ◽  
Pulmonary Blood Flow ◽  
Dilution Method ◽  
Moderate Exercise ◽  
Tolerance Limits ◽  
Dye Dilution ◽  
Single Breath ◽  
Significant Difference ◽  
Anesthetized Dogs ◽  
Single Breath Method

We have evaluated the single-breath method of Kim, Rahn, and Fahri (J. Appl. Physiol. 21: 1338, 1966) using anesthetized dogs (avg wt 26 kg). The systematic error was determined by comparing the single-breath estimates of cardiac output with values obtained by the dye-dilution method. In some dogs the effects of moderate exercise were stimulated by joining the circulations of two dogs. From paired estimates, the random error of the single-breath method was +/- 12% (95% tolerance limits; 23 pairs) over a range of outputs 1.1-5.0 l/min. There was no significant difference between values of cardiac output by the single-breath method and by dye dilution, and in four dogs the dye-dilution values were not significantly different from values of pulmonary blood flow controlled by perfusion. These results indicate that under carefully controlled conditions the single-breath method is capable of providing reliable estimates of cardiac output.

Evaluation of a method for estimating cardiac output from a single breath in humans

1982 ◽  
Vol 53 (4) ◽  
pp. 1034-1038 ◽  
Author(s):  
H. Chen ◽  
N. P. Silverton ◽  
R. Hainsworth
Keyword(s):  
Cardiac Output ◽  
Normal Subjects ◽  
Random Errors ◽  
Tolerance Limits ◽  
Mean Values ◽  
Single Breath ◽  
Significant Difference ◽  
Venous Pco2 ◽  
Mixed Venous ◽  
Single Breath Method

We have modified the single-breath method of Kim et al. (J. Appl. Physiol. 21: 1338–1344, 1966) for estimating cardiac output and arterial and mixed venous carbon dioxide tensions (PCO2). We assessed this using 30 normal subjects and 23 cardiac patients. The procedure was performed satisfactorily in all but two patients. The random errors, from 60 pairs of estimates of cardiac output in normal subjects and 50 pairs in patients, were +/- 12.8 and +/- 19.6% (95% tolerance limits; i.e., coefficient of variation multiplied by 2 for n greater than 50). The systematic error was assessed in 15 patients from comparisons with results obtained by the direct Fick method. There was no significant difference except in two patients with large intracardiac shunts. Mean values of cardiac output by single-breath and direct Fick estimates were 3.80 and 3.83 l/min. Arterial and mixed venous PCO2 were estimated by the single-breath method with random errors of +/- 1.5 and +/- 1.4 Torr, respectively, and no significant systematic errors. We conclude that our modification of the single-breath method is reliable in humans at rest, although the procedures for delivering the breath and processing the data are of critical importance.

Effect of breath-hold time on DLCO(SB) in patients with airway obstruction

1985 ◽  
Vol 58 (4) ◽  
pp. 1319-1325 ◽  
Author(s):  
B. L. Graham ◽  
J. T. Mink ◽  
D. J. Cotton
Keyword(s):  
Hold Time ◽  
Phase Iii ◽  
Breath Holding ◽  
Breath Hold ◽  
Single Breath ◽  
Incomplete Mixing ◽  
Capillary Membrane ◽  
Phase Iii Slope ◽  
Alveolar Capillary ◽  
Short Breath

The single-breath diffusing capacity of the lung for CO [DLCO(SB)] is considered a measure of the conductance of CO across the alveolar-capillary membrane and its binding with hemoglobin. Although incomplete mixing of inspired gas with alveolar gas could theoretically influence overall diffusion, conventional calculations of DLCO(SB) spuriously overestimate DLCO(SB) during short breath-holding periods when incomplete mixing of gas within the lung might have the greatest effect. Using the three-equation method to calculate DLCO(SB) which analytically accounts for changes in breath-hold time, we found that DLCO(SB) did not change with breath-hold time in control subjects but increased with increasing breath-hold time in both patients with asthma and patients with emphysema. The increase in DLCO(SB) with increasing breath-hold time correlated with the phase III slope of the single-breath N2 washout curve. We suggest that in patients with ventilation maldistribution, DLCO(SB) may be decreased for the shorter breath-hold maneuvers because overall diffusion is limited by the reduced transport of CO from the inspired gas through the alveolar gas prior to alveolar-capillary gas exchange.

scholarly journals Standardisation and application of the single-breath determination of nitric oxide uptake in the lung

2017 ◽  
Vol 49 (2) ◽  
pp. 1600962 ◽  
Author(s):  
Gerald S. Zavorsky ◽  
Connie C.W. Hsia ◽  
J. Michael B. Hughes ◽  
Colin D.R. Borland ◽  
Hervé Guénard ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Hold Time ◽  
Haemoglobin Concentration ◽  
Specific Conductance ◽  
Breath Holding ◽  
Breath Hold ◽  
Diffusing Capacity ◽  
Detection Range ◽  
Single Breath ◽  
Alveolar Oxygen

Diffusing capacity of the lung for nitric oxide (DLNO), otherwise known as the transfer factor, was first measured in 1983. This document standardises the technique and application of single-breathDLNO. This panel agrees that 1) pulmonary function systems should allow for mixing and measurement of both nitric oxide (NO) and carbon monoxide (CO) gases directly from an inspiratory reservoir just before use, with expired concentrations measured from an alveolar “collection” or continuously sampledviarapid gas analysers; 2) breath-hold time should be 10 s with chemiluminescence NO analysers, or 4–6 s to accommodate the smaller detection range of the NO electrochemical cell; 3) inspired NO and oxygen concentrations should be 40–60 ppm and close to 21%, respectively; 4) the alveolar oxygen tension (PAO2) should be measured by sampling the expired gas; 5) a finite specific conductance in the blood for NO (θNO) should be assumed as 4.5 mL·min-1·mmHg-1·mL-1of blood; 6) the equation for 1/θCO should be (0.0062·PAO2+1.16)·(ideal haemoglobin/measured haemoglobin) based on breath-holdingPAO2and adjusted to an average haemoglobin concentration (male 14.6 g·dL−1, female 13.4 g·dL−1); 7) a membrane diffusing capacity ratio (DMNO/DMCO) should be 1.97, based on tissue diffusivity.

A Study of Factors Influencing Relief of Discomfort in Breath-Holding in Normal Subjects

1974 ◽  
Vol 47 (3) ◽  
pp. 193-199 ◽  
Author(s):  
J. R. A. Rigg ◽  
A. S. Rebuck ◽  
E. J. M. Campbell
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Breaking Point ◽  
Breath Holding ◽  
Breath Hold ◽  
Afferent Activity ◽  
Local Pressure ◽  
Single Breath ◽  
Afferent Information ◽  
Series Of Experiments

1. Two series of experiments were performed in an attempt to elucidate the mechanism of relief of the discomfort of breath-holding. 2. In the first the effect of varying the size of a single breath at the breaking point of breath-holding on the time of a second breath-hold (BHT2) was observed in three normal subjects. The effect of two different non-ventilatory chest-wall manœuvres, performed at the breaking point, on the duration of a second breath-hold in two additional subjects was then studied. 3. The volume of an unrestricted relieving breath was always greater than 70% of vital capacity. When the size of the breath was restricted to as little as 20% of the free relieving volume, BHT2 was unchanged. 4. An inspiratory effort against an occluded airway or an isovolume movement of the rib cage and abdomen performed at the breaking point of breath-holding were as effective as a control relieving breath in allowing resumption of apnoea. 5. There seem to be two possible mechanisms of relief. First, afferent information may be generated by some consequence of diaphragmatic contraction. Secondly, changes of local pressure-volume relationships within the lung may alter the pattern of vagal afferent activity, independent of an overall change in lung volume.

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.

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