Respiratory Mechanics in Infants and Young Children Before and After Repair of Left-to-Right Shunts

Baraldi, Eugenio; Filippone, Marco; Milanesi, Ornella; Magagnin, Giampiero; Vencato, F; Barbieri, Paola; Pellegrino, P A; Zacchello, Franco

doi:10.1203/00006450-199309000-00018

Cited by 23 publications

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“…Some investigations have revealed a clear correlation between an elevated Ppa and the subsequent changes in the mechanical properties of the lungs (2,13,23,27,28), although the increases in Ppa were always associated with increases in pulmonary venous pressures in those investigations. Other studies failed to detect any change in lung function in the presence of an elevated Ppa (3,6,7,11,22,26). The findings of the present study are in accord with the latter observations, demonstrating only poor quantitative relationships between Ppa and the lung mechanical parameters.…”

Section: Pulmonary Hemodynamics Affect Lung Mechanicssupporting

confidence: 90%

“…In other reports, it was found that an elevated Q p affects lung mechanics only when high pulmonary vascular pressures are also present (2,3,20,26). The conclusions of all these previous investigations were based on measurements in children with various congenital heart diseases (2,3,13,20,22,26) or after administration of a pulmonary vasodilator drug (9). Nevertheless, because the changes in Q p were always associated with changes in pulmonary pressures in those studies, it is difficult to identify the separate roles of the abnormal pulmonary circulatory pressure and flow from the measurements.…”

Section: Pulmonary Hemodynamics Affect Lung Mechanicsmentioning

confidence: 92%

“…Changes induced in the pulmonary vasculature by chronic heart-lung diseases, such as thickening of the pulmonary vasculature (30), did not fall in the scope of this study. Although acute and chronic effects are involved in clinical situations, the immediate improvement in lung function after surgery for congenital heart diseases (1,3,15,20,22,24) suggests that acute effects play a significant role in the compromised lung function.…”

Section: Pulmonary Hemodynamics Affect Lung Mechanicsmentioning

confidence: 99%

“…Conversely, a high Ppa has been demonstrated to play a major role in determining the mechanical properties of the lungs, since changes were observed only when Ppa was elevated (2,15,27,28). Finally, other authors observed abnormal lung function only when an increased Q p was associated with an elevated Ppa (3,20).…”

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confidence: 99%

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Effects of pulmonary vascular pressures and flow on airway and parenchymal mechanics in isolated rat lungs

Peták

Habre

Hantos

et al. 2002

Journal of Applied Physiology

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Changes in pulmonary hemodynamics have been shown to alter the mechanical properties of the lungs, but the exact mechanisms are not clear. We therefore investigated the effects of alterations in pulmonary vascular pressure and flow (Q p) on the mechanical properties of the airways and the parenchyma by varying these parameters independently in three groups of isolated perfused normal rat lungs. The pulmonary capillary pressure (Pcest), estimated from the pulmonary arterial (Ppa) and left atrial pressure (Pla), was increased at constant Q p (n ϭ 7), or Q p was changed at Pcest ϭ 10 mmHg (n ϭ 7) and at Pcest ϭ 20 mmHg (n ϭ 6). In each condition, the airway resistance (Raw) and parenchymal damping (G) and elastance (H) were identified from the low-frequency pulmonary input impedance spectra. The results of measurements made under isogravimetric conditions were analyzed. The changes observed in the mechanical parameters were consistent with an altered Pla: monotonous increases in Raw were observed with increasing Pla, whereas G and H were minimal at Pla of ϳ7-10 mmHg and increased at lower and higher Pla. The results indicate that Pla, and not Ppa or Q p, is the primary determinant of the mechanical condition of the lungs after acute changes in pulmonary hemodynamics: the parenchymal mechanics are impaired if Pla is lower or higher than physiological, whereas airway narrowing occurs at high Pla. respiratory mechanics; forced oscillations; pulmonary circulation

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Section: Pulmonary Hemodynamics Affect Lung Mechanicssupporting

confidence: 90%

Section: Pulmonary Hemodynamics Affect Lung Mechanicsmentioning

confidence: 92%

Section: Pulmonary Hemodynamics Affect Lung Mechanicsmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of pulmonary vascular pressures and flow on airway and parenchymal mechanics in isolated rat lungs

Peták

Habre

Hantos

et al. 2002

Journal of Applied Physiology

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“…This aspect has been studied mainly in infants with various congenital heart defects causing different ratios of pulmonary to systemic blood flow [1,2,3,4,5], and in infants after surgical correction of left to right shunts [6,7], after induction of a left to right shunt [8], or correction of pulmonary hyper- or hypoperfusion [9]. The results of these studies suggest that a high pulmonary blood flow may be associated with increased pulmonary elastance and airway resistance [10,11].…”

Section: Introductionmentioning

confidence: 99%

Effects of Acute Blood Volume Expansion on Respiratory Mechanics in the Rat

et al. 2009

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Backgrounds: The effects of acute blood volume expansion (BVE) on the respiratory mechanics of normal animals have been not extensively studied. The subject is of both theoretical and practical interest since BVE is a frequent medical intervention, and the associated increase in cardiac output may occur in different physiopathological situations. Objectives: To describe the changes in the parameters of respiratory mechanics occurring as an effect of acute BVE and the related increase in cardiac output. Methods: We applied the end-inflation occlusion method in normal, positive pressure-ventilated rats to measure the respiratory mechanics under control and BVE conditions. Results: Under BVE conditions, we found a statistically significant increase in static respiratory system elastance (E_st,rs), ohmic airway resistance plus resistance of respiratory system tissues to movement (R_min,rs), and overall resistance including pendelluft and stress relaxation effects (R_max,rs). Under BVE conditions, the resistive component due to sole stress relaxation and pendelluft (R_visc,rs) increased almost significantly while a significant increment in mean respiratory system hysteresis surface area (Hy_rs) was also found. Conclusions: Increasing pulmonary blood flow by BVE increases the mechanical work of breathing because of the effects on E_st,rs, R_min,rs and R_max,rs, and because of the increase in Hy_rs.

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Preoperative pulmonary hemodynamics determines changes in airway and tissue mechanics following surgical repair of congenital heart diseases

Habre

Schütz

Pellégrini

et al. 2004

Pediatric Pulmonology

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To characterize the effect of changes in pulmonary hemodynamics on airway and tissue mechanics, forced oscillatory input impedance of the respiratory system (Zrs) was measured between 0.4-12 Hz in two groups of children undergoing surgical repair of congenital heart disease (CHD) immediately before sternotomy and after chest closure during short apneic intervals. Children with lesions associated with high pulmonary blood flow and/or pressure (septal defects; HP group, n = 12) and children with hypoperfused lungs (tetralogy of Fallot; LP group, n = 12) were included in the study. Airway resistance (Raw), and coefficients of respiratory tissue damping (G) and elastance (H), were estimated from Zrs by model-fitting. A postoperative reduction in pulmonary blood flow and/or pressure in the HP group resulted in an immediate decrease in Raw of 29 +/- 9 (SE)% (P < 0.05), whereas children in the LP group had increases in Raw (24 +/- 17%, no significance) after surgery. No significant change was observed in G in either the HP (6.4 +/- 13%) or LP (27 +/- 23%) group, while H increased in children of both the HP (23 +/- 8%, P < 0.05) and LP (36 +/- 7%, P < 0.01) groups. These results suggest that the preoperative pulmonary hemodynamic condition determines changes in airway mechanics: surgical repair of CHD leads to an improvement in airway function only in children with congested lungs. The adverse effects of surgery, mechanical ventilation, and/or cardiopulmonary bypass may be responsible for the increased stiffness of the respiratory system observed in both groups of children.

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Respiratory Mechanics in Infants and Young Children Before and After Repair of Left-to-Right Shunts

Cited by 23 publications

References 0 publications

Effects of pulmonary vascular pressures and flow on airway and parenchymal mechanics in isolated rat lungs

Effects of pulmonary vascular pressures and flow on airway and parenchymal mechanics in isolated rat lungs

Effects of Acute Blood Volume Expansion on Respiratory Mechanics in the Rat

Preoperative pulmonary hemodynamics determines changes in airway and tissue mechanics following surgical repair of congenital heart diseases

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