Influence of state of inflation of the lung on pulmonary vascular resistance

Whittenberger, James L.; McGregor, Maurice; Berglund, Erik; Borst, H. G.

doi:10.1152/jappl.1960.15.5.878

Cited by 313 publications

(142 citation statements)

References 0 publications

Supporting

Mentioning

118

Contrasting

Unclassified

Order By: Relevance

“…12). This finding implies that airway pressure primarily reduced the cross-sectional area of the pulmonary arterioles and capillaries, consistent with the hypothesis of Whittenberger et al 25 Because characteristic impedance remained constant, the lumped pro'perties of the larger pulmonary vessels did not seem to change. Therefore, the primary effect of airway pressure on the pulmonary circulation was to increase the mean pulmonary vascular resistance while the proportion of total right ventricular work due to oscillatory work was reduced (table 2).…”

Section: Circulationsupporting

confidence: 88%

The effects of airway pressure on cardiac function in intact dogs and man.

Rankin¹,

Olsen²,

Arentzen³

et al. 1982

Circulation

142

View full text Add to dashboard Cite

Ventilation with positive end-expiratory pressure (PEEP) is associated with reduced cardiac output, but the mechanisms involved are controversial. Possible explanations include increased intrathoracic pressure, reflex changes in myocardial inotropism, pulmonary vascular obstruction and abnormal ventricular interaction. Three types of conscious canine preparations were developed to examine simultaneously each of these factors during ventilation with PEEP. In addition, similar measurements were obtained in patients after cardiac surgical procedures and compared with the results of animal experiments. The primary cause of reduced cardiac output during PEEP appeared to be a diminished end-diastolic volume of the left ventricle, and this appeared to be the result of elevated intrathoracic pressure and increased impedance to blood flow through the lungs. Abnormal interventricular septal shifting and reflex autonomic alterations did not appear to be significant in the normal cardiovascular system. These data provide insight into the cardiac effects of PEEP and emphasize the importance of simultaneous quantification of biventricular performance when assessing cardiopulmonary function.

show abstract

Section: Circulationsupporting

confidence: 88%

The effects of airway pressure on cardiac function in intact dogs and man.

Rankin¹,

Olsen²,

Arentzen³

et al. 1982

Circulation

142

View full text Add to dashboard Cite

show abstract

“…In fact, PVR increases as much as lung volume increases [32]. An increase in right ventricular afterload with consequent reduction in cardiac output and rise in PAOP has been described in COPD patients during AVF [2].…”

Section: Dynamic Hyperinflationmentioning

confidence: 99%

Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure

Dambrosio¹,

Brienza²

1996

Eur Respir J

View full text Add to dashboard Cite

Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure. V.M. Ranieri, M. Dambrosio, N. Brienza. ERS Journals Ltd 1996. ABSTRACT: Deviation of end-expiratory lung volume from the elastic equilibrium volume of the respiratory system is recognized as a cardinal feature in mechanically-ventilated patients with severe chronic obstructive pulmonary disease (COPD) and acute ventilatory failure (AVF). The presence of dynamic hyperinflation implies that alveolar pressure remains positive throughout expiration. At the end of the expiration, this positive pressure is named intrinsic positive end-expiratory pressure (PEEPi).Recent studies have suggested that, in COPD patients with expiratory flow limitation, the application of external PEEP during assisted mechanical ventilation, or the use of continuous positive airway pressure (CPAP) in spontaneously breathing patients, can counterbalance and reduce the inspiratory threshold load imposed by PEEPi, without causing further increase in lung volume and alveolar and intrathoracic pressures until a critical value of PEEP (Pcrit) is reached. Above this critical limit further hyperinflation is observed.A specific and characteristic role of PEEPi in compromising the heart function in COPD patients during AVF may be identified based on: 1) an increase in right ventricular impedance due to lung hyperinflation; 2) an increase in the venous return to the right ventricle and, consequently, a leftward shift of the septum caused by the large negative deflections in intrathoracic pressure due to the inspiratory threshold load; 3) a further increase in venous return to the right ventricle, with the eventual collapse of the vena cava caused by the expiratory recruitment of abdominal muscles; and 4) hypoxia and hypercapnia consequent to acute ventilatory failure, which may further increase right ventricular impedance and venous return to the right ventricle.All these phenomenon are directly correlated to the large negative intrathoracic pressure developed by the respiratory muscles to overcome the inspiratory threshold caused by intrinsic positive end-expiratory pressure (preload effect), and to the increase in lung volume (afterload effect). Application of positive end-expiratory pressure/continuous positive airway pressure in chronic obstructive pulmonary disease patients during acute ventilatory failure may, hence, unload the respiratory muscles as well as the heart. Eur Respir J., 1996Respir J., , 9, 1283Respir J., -1292

show abstract

“…Furthermore, sympathetic outflow can be diminished by reducing work of breathing and by increasing alveolar ventilation to attenuate respiratory acidosis. The relationship between lung volume and PVR is U-shaped with increased PVR occuring at low lung volumes (due to increased resistance in extra-alveolar vessels and alveolar collapse increasing HPV) and at high lung volumes (due to hyperinflation and increased alveolar pressure compressing alveolar vessels) (Whittenberger et al, 1960). PVR is lowest at FRC that is typically reduced in ALI.…”

Section: Heart-lung Interactions and Mechanical Ventilationmentioning

confidence: 99%