Compliance of the main pulmonary artery during the ventilatory cycle

1992 ◽  
Vol 72 (2) ◽  
pp. 535-542 ◽  
Author(s):  
B. J. Grant ◽  
B. B. Lieber
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Arterial Pressure ◽  
Arterial Compliance ◽  
Unit Length ◽  
Main Pulmonary Artery ◽  
Time Varying ◽  
Positive End Expiratory Pressure ◽  
Pulmonary Arterial ◽  
The Mean ◽  
Phase Differences

Transmural pulmonary arterial pressure (Ppa), diameter (D), and length (L) of a segment of the main pulmonary artery (MPA) were measured simultaneously in anesthetized open-chest dogs. The instantaneous volume was calculated from D and L. Pulmonary arterial elasticity for diameter (EpD) was calculated as the ratio of the amplitude of Ppa to D oscillation normalized by the mean D. Similar indexes were calculated for L (EpL) and V (Epv). Compliance per unit length was calculated from the dimensions and elasticity of the MPA. Under control conditions with 5 cmH2O positive end-expiratory pressure, EpD, EpL, and Epv at cardiac frequency were 175 +/- 27, 147 +/- 27, and 55 +/- 7 cmH2O, respectively. EpD increased with positive end-expiratory pressure, but EpL decreased and Epv was unaffected. EpD, EpL, Epv, and compliance per unit length were not significantly different between the start of inspiration and the start of expiration. In addition, there were no significant phase differences between the oscillations of Ppa and V at respiratory frequency. We conclude that the previously reported time variation of pulmonary arterial compliance during the ventilatory cycle is not due to time-varying properties of the MPA.

Time-varying pulmonary arterial compliance

1991 ◽  
Vol 70 (2) ◽  
pp. 575-583 ◽  
Author(s):  
B. J. Grant ◽  
J. M. Fitzpatrick ◽  
B. B. Lieber
Keyword(s):  
Pulmonary Artery ◽  
Lung Volume ◽  
Input Impedance ◽  
Arterial Compliance ◽  
Main Pulmonary Artery ◽  
Impedance Spectrum ◽  
Lumped Parameter Model ◽  
Positive Pressure ◽  
Time Varying ◽  
Pulmonary Arterial

We tested the hypothesis that pulmonary arterial compliance (Ca) varies during the ventilatory cycle. Pressure and flow in the main pulmonary artery were measured in open-chest dogs under chloralose anesthesia (n = 12) with a positive-pressure volume-cycled ventilator. Input impedance was calculated from the pressure and flow waves of heart cycles obtained immediately after the start of inspiration (SI) and immediately after the start of expiration (SE). A lumped parameter model was used to calculate Ca from the input impedance spectrum of the main pulmonary artery. Three levels of positive end-expiratory pressure (PEEP) were used before and after meclofenamate (n = 6) or vagotomy (n = 6). Ca was significantly greater at SE than at SI at each level of PEEP. PEEP increased Ca at SE but not at SI. None of these changes was altered by meclofenamate or vagotomy, suggesting that these differences of Ca were due to passive mechanical effects rather than an active neurohumoral mechanisms. We conclude that Ca is time varying during the ventilatory cycle because it is altered by the dynamic increase of lung volume between SI and SE, but not with the quasi-static increase of lung volume induced by raising the level of PEEP. These changes of Ca were unaffected by vagal feedback or inhibition of cyclooxygenase. We suggest that the increased Ca just after the start of expiration may result from dynamic shifts of blood volume from the extra-alveolar to the alveolar vessels.

scholarly journals Main pulmonary artery diameter assessment in a large sample of Indian population: a MDCT based study

2019 ◽  
Vol 5 (6) ◽  
pp. 145
Author(s):  
Abdul Haseeb Wani ◽  
Yassar Shiekh ◽  
Najeeb Tallal Ahangar
Keyword(s):  
Pulmonary Artery ◽  
Main Pulmonary Artery ◽  
Normative Values ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Enhanced Ct ◽  
Significant Difference ◽  
Pulmonary Arterial ◽  
The Mean ◽  
Pulmonary Artery Diameter

<p class="abstract"><strong>Background:</strong> The gold standard for pulmonary artery pressure measurement is right heart catheterization but its invasive nature precludes its routine use. Main pulmonary arterial trunk calibre increase is a strong indicator of underlying pulmonary arterial hypertension. MDCT can accurately measure the diameter of main pulmonary artery. The objective of the study was to establish the normative values of main pulmonary artery caliber using contrast enhanced CT and try to ascertain any significant difference in main pulmonary artery calibers between two genders and correlation of age and main pulmonary artery diameter.</p><p class="abstract"><strong>Methods:</strong> Contrast enhanced CT images of 462 subjects were analysed on a PACS workstation monitor and widest diameter perpendicular to long axis of the main pulmonary artery as seen on reformatted axial image was measured with electronic caliper tool at the level of the main pulmonary artery bifurcation.  </p><p class="abstract"><strong>Results:</strong> The mean main pulmonary artery diameter in females was 22.54±2.19 mm and 23.34±3.06 mm in males. The mean pulmonary artery diameter in males was larger than females with statistically significant difference seen (p&lt;0.05). The correlation coefficient between age of whole sample and their mean main pulmonary artery was found to be 0.1006 with no statistically significant difference.</p><p class="abstract"><strong>Conclusions:</strong> There is a statistically significant difference in the mean main pulmonary artery calibre between males and females with no strong correlation between the age and mean main pulmonary artery calibre. Further studies are warranted to find the complex interaction between main pulmonary artery diameter and sex, age and body mass index.</p>

Pulmonary arterial elasticity in awake dogs

1993 ◽  
Vol 75 (2) ◽  
pp. 840-848 ◽  
Author(s):  
B. J. Grant ◽  
J. M. Canty ◽  
G. Srinivasan ◽  
A. S. Brody
Keyword(s):  
Computed Tomography ◽  
Pulmonary Artery ◽  
Pulmonary Arterial Pressure ◽  
Main Pulmonary Artery ◽  
Arterial Elasticity ◽  
Cross Sectional ◽  
Anesthetized Dogs ◽  
Pulmonary Arterial ◽  
The Relationship ◽  
Made In

We measured the relationship between pulmonary arterial pressure (Ppa), diameter (D), and length of a segment of the main pulmonary artery (MPA) in chronically instrumented conscious dogs breathing spontaneously (CCC). There were no physiologically significant changes in Ppa or D in the CCC dogs postoperatively, and the cross-sectional MPA shape measured by fast computed tomography was nearly circular. These results suggest that the MPA was not distorted by chronic instrumentation. We compared measurements made in the CCC dogs with previous measurements in acutely instrumented anesthetized dogs with open chests (AAO). The elasticity of MPA in the CCC animals was frequency dependent between 1 and 14 Hz and was similar to that in the AAO dogs. Oscillations of D preceded Ppa at cardiac frequencies in the AAO animals, but the D and Ppa oscillations were in phase in the CCC animals. The oscillations of length relative to D were significantly less in the CCC than in the AAO dogs. We conclude that, with limitations, the hemodynamic properties of the MPA can be measured in the CCC subjects. We suggest that the discrepancies between the AAO and CCC dogs can be attributed to differences in extrinsic loading of the MPA.

scholarly journals Transcatheter radiofrequency pulmonary artery denervation in swine: the evaluation of lesion degree, hemodynamics and pulmonary hypertension inducibility

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Natalia S. Goncharova ◽  
Heber Ivan Condori Leandro ◽  
Aleksandr D. Vakhrushev ◽  
Elena G. Koshevaya ◽  
Yury A. Skorik ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Controlled Study ◽  
Group Iii ◽  
Group I ◽  
Before And After ◽  
Pulmonary Arterial ◽  
The Mean

Abstract Background Mechanisms of positive effects of pulmonary artery (PA) denervation (PADN) remain poorly understood. The study aimed to evaluate pulmonary hemodynamic changes after PADN and their association with the extent of PA wall damage in an acute thromboxane A2 (TXA2)-induced pulmonary hypertension (PH) model in swine. Methods In this experimental sham-controlled study, 17 normotensive male white Landrace pigs (the mean weight 36.2 ± 4.5 kg) were included and randomly assigned to group I (n = 9)—PH modeling before and after PADN, group II (n = 4)—PADN only, or group III (n = 4)—PH modeling before and after a sham procedure. Radiofrequency (RF) PADN was performed in the PA trunk and at the proximal parts of the right and left PAs. PA wall lesions were characterized at the autopsy study using histological and the immunohistochemical examination. Results In groups I and II, no statistically significant changes in the mean pulmonary arterial pressure nor systemic blood pressure were found after PADN (−0.8 ± 3.4 vs 4.3 ± 8.6 mmHg, P = 0.47; and 6.0 ± 15.9 vs -8.3 ± 7.5 mmHg, P = 0.1; correspondingly). There was a trend towards a lower diastolic pulmonary arterial pressure after PADN in group I when compared with group III during repeat PH induction (34.4 ± 2.9 vs 38.0 ± 0.8; P = 0.06). Despite the presence of severe PA wall damage at the RF application sites, S100 expression was preserved in the majority of PA specimens. The presence of high-grade PA lesions was associated with HR acceleration after PADN (ρ = 0.68, p = 0.03). No significant correlation was found between the grade of PA lesion severity and PA pressure after PADN with or without PH induction. Conclusions Extended PADN does not affect PH induction using TXA2. Significant PA adventitia damage is associated with HR acceleration after PADN. Possible delayed effects of PADN on perivascular nerves and pulmonary hemodynamics require further research in chronic experiments.

Effect of RBC shape and deformability on pulmonary O2 diffusing capacity and resistance to flow in rabbit lungs

1995 ◽  
Vol 78 (3) ◽  
pp. 778-783 ◽  
Author(s):  
D. C. Betticher ◽  
W. H. Reinhart ◽  
J. Geiser
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Oxygen Transfer ◽  
Sodium Salicylate ◽  
Pulmonary Arterial Pressure ◽  
Diffusing Capacity ◽  
Artery Pressure ◽  
Human Red Blood Cells ◽  
Pulmonary Arterial ◽  
The Mean

Isolated rabbit lungs were perfused with washed and resuspended human red blood cells (RBCs) in the presence of drugs known to change the shape and deformability of RBCs. With sodium salicylate (0.5–2 g/l), which causes echinocytosis and increases RBC deformability, lung diffusing capacity for O2 (DLO2) increased by 21%. When chlorpromazine, which induces stomatocytosis and stiffens RBCs, was given (50 mg/l), DLO2 decreased by 18%. With sodium salicylate, the mean pulmonary artery pressure dropped by 14% from control values, whereas it increased by 18% under chlorpromazine. Comparative experiments with hemoglobin solutions did not reveal any effect of those two drugs either on DLO2 or on pulmonary arterial pressure, which indicates that the effects of sodium salicylate and chlorpromazine were due to changes in RBC shape and deformability. It is concluded that RBC shape and deformability affect pulmonary artery pressure and oxygen diffusing capacity, which may have an influence on oxygen transfer to tissue and hence be of clinical relevance.

Pulmonary capillaries are recruited during pulsatile flow

2002 ◽  
Vol 92 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Robert G. Presson ◽  
William A. Baumgartner ◽  
Amanda J. Peterson ◽  
Robb W. Glenny ◽  
Wiltz W. Wagner
Keyword(s):  
Pulsatile Flow ◽  
Left Atrial ◽  
Pulmonary Arterial Pressure ◽  
Pressure Rise ◽  
Capillary Recruitment ◽  
Pulmonary Capillaries ◽  
Pulmonary Capillary ◽  
Direct Measurements ◽  
Pulmonary Arterial ◽  
The Mean

Capillaries recruit when pulmonary arterial pressure rises. The duration of increased pressure imposed in such experiments is usually on the order of minutes, although recent work shows that the recruitment response can occur in <4 s. In the present study, we investigate whether the brief pressure rise during cardiac systole can also cause recruitment and whether the recruitment is maintained during diastole. To study these basic aspects of pulmonary capillary hemodynamics, isolated dog lungs were pump perfused alternately by steady flow and pulsatile flow with the mean arterial and left atrial pressures held constant. Several direct measurements of capillary recruitment were made with videomicroscopy. The total number and total length of perfused capillaries increased significantly during pulsatile flow by 94 and 105%, respectively. Of the newly recruited capillaries, 92% were perfused by red blood cells throughout the pulsatile cycle. These data provide the first direct account of how the pulmonary capillaries respond to pulsatile flow by showing that capillaries are recruited during the systolic pulse and that, once open, the capillaries remain open throughout the pulsatile cycle.

A computed method for noninvasive MRI assessment of pulmonary arterial hypertension

2004 ◽  
Vol 96 (2) ◽  
pp. 463-468 ◽  
Author(s):  
Eric Laffon ◽  
Christophe Vallet ◽  
Virginie Bernard ◽  
Michel Montaudon ◽  
Dominique Ducassou ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Cross Sectional Area ◽  
Physical Parameters ◽  
Sectional Area ◽  
Biophysical Parameters ◽  
Cross Sectional ◽  
Mean Pulmonary Arterial Pressure ◽  
Pulmonary Arterial ◽  
The Mean

The present method enables the noninvasive assessment of mean pulmonary arterial pressure from magnetic resonance phase mapping by computing both physical and biophysical parameters. The physical parameters include the mean blood flow velocity over the cross-sectional area of the main pulmonary artery (MPA) at the systolic peak and the maximal systolic MPA cross-sectional area value, whereas the biophysical parameters are related to each patient, such as height, weight, and heart rate. These parameters have been measured in a series of 31 patients undergoing right-side heart catheterization, and the computed mean pulmonary arterial pressure value (PpaComp) has been compared with the mean pressure value obtained from catheterization (PpaCat) in each patient. A significant correlation was found that did not differ from the identity line PpaComp = PpaCat ( r = 0.92). The mean and maximal absolute differences between PpaComp and PpaCat were 5.4 and 11.9 mmHg, respectively. The method was also applied to compute the MPA systolic and diastolic pressures in the same patient series. We conclude that this computed method, which combines physical (whoever the patient) and biophysical parameters (related to each patient), improves the accuracy of MRI to noninvasively estimate pulmonary arterial pressures.

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