Archive for the 'Cardiology' Category

12 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Conclusion

There is evidence that the vagal reflexes induced by lung vascular congestion are activated, at least in part, by the accumulation of extravascular lung water rather than by high vascular pressures per se. Moreover, it is well known that interstitial edema responds slowly to changes in vascular pressures. In experimental hydrostatic lung edema, vagally mediated […]

11 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Specificity of Zrs to Acute Pulmonary Vascular Congestion

Specificity of Zrs to Acute Pulmonary Vascular Congestion The Zrs modifications observed in cardiac patients during the acute study appear to be qualitatively similar to those in asthmatic patients with severe airway obstruction (Fig 1). The latter were examined in the sitting position. However, we can infer from the effects of body position on Zrs […]

10 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Discussion

Reference Values In order to evaluate semirecumbent cardiac patients for possible Zrs abnormalities, appropriate reference Zrs values are needed. The normal values of Zrs published in the literature were recorded in ambulatory subjects in the sitting position and therefore may not be relevant to measurements obtained in hospitalized, semirecumbent patients. This is partly due to […]

09 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Results

In Figure 1, the mean resistance and reactance curves obtained in normal subjects (group N), cardiac patients (group C), and asthmatic patients (group A) can be compared. The latter group was characterized by severe airway obstruction as shown by the functional values displayed in the last line of Table 2. In group N, resistance was […]

08 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Hemodynamic Measurements

Hemodynamic Measurements Right heart catheterization was performed by the flow-directed balloon-tipped catheter technique. The pressures were measured in the supine position. The hydrostatic zero was set at 5 cm below the sternal angle. Prior to use, the pressure transducer (Trantec, Bentley) was calibrated against a mercury manometer. Cardiac output was determined by the thermodilution technique […]

07 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure: Patients and Methods

All patients had a Swan-Ganz catheter inserted for guiding therapy. All had a pulmonary capillary wedge pressure (Pw) >20 mm Hg. One acute and two follow-up studies were performed. During the acute study, each patient had 2 to 6 Zrs measurements made in a semirecumbent position, the first of those made within the 24 h […]

06 Jan

Respiratory Acoustic Impedance in Left Ventricular Failure

Alterations in lung mechanics have been shown to L occur early in pulmonary vascular congestion. In particular, a reversible decrease in lung compliance has been observed in animal and in man during the phase of rapid rise in left ventricular filling pressure. These modifications appear before accumulation of interstitial fluid and therefore precede clinical signs […]

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