Clinical And Experimental Study On The Rule Of Respiratory Changes Of The Spectrum Of Superior Vena Cava

Objectives Aimed to study the rule of respiratory changes of the spectra of superior venae cavae (SVC) of health adults, explore the relationships between the parameters of the spectra of SVC and intrathoracic pressure (TIP) and right atrium pressure (RAP), and evaluate the clinical value of respiratory changes of the spectra of SVC through studying the characteristics of respiratoiy changes of the spectra of SVC in patients with right heart failure.Methods 1. Through supraclavicular fossa view, maximum and minimum return flow velocity spectra of SVC of health adults in respiration cycle were recorded, peak velocities and velocity time integrals (VTI) of them were measured, and the change ratios were calculated. 2. Various ITP (-8 mmHg, -4 mmHg, 4 mmHg and 8 mmHg) were obtained by respiratory mask, the spectra of SVC of health adults under various ITP were recorded, and the parameters of SVC were measured accordingly. 3. Canine models with different RAP (5mmHg, 10mmHg and 15mmHg) were constructed through infusing hypertonic saline rapidly, and the respiratory changes of the parameters of the spectra of SVC were calculated accordingly. 4. The spectra of SVC in patients with right heart failure and their...