心肺交互作用(simplified).ppt

Patterns of cardiac function and plasma catecholamine levels differed between patients who did or did not achieve spontaneous ventilation with a trial of continuous positive airway pressure. Cardiac function must be systematically considered before and during the return to spontaneous ventilation to optimize the likelihood of success. Susan KF. American Journal of Critical Care. 2006;15:580-594 Effects of increase in airway pressure and volume on right and left ventricle Heart-lung interactions may play a role in the manifestations and treatment of a variety of disorders Using heart–lung interactions (PPV) can assess fluid responsiveness during mechanical ventilation Cardiac function must be systematically considered before and during the return to spontaneous ventilation to optimize the likelihood of success 谢谢 Anaesthesiology 1997,86:308-315 RH and intrathoracic great veins are subjected to pleural pressure (PPl ) , which varies throughout the respiratory cycle. IAP increases with inspiratory diaphragmatic descent, and normalises to atmospheric (Patmos ) with expiration. Peripheral venous pressure is unaffected by respiration and so remains at atmospheric pressure throughout the respiratory cycle. Systemic venous drainage (broken arrow) depends on a driving pressure gradient between extrathoracic great veins (EGV) and the right atrium, and so during spontaneous respiration is maximised during inspiration as the pleural (and right atrial) pressure falls, and the intra-abdominal (and therefore EGV) pressure rises Negative swings in intrathoracic pressure —for example, during a Mueller manoeuvre (deep inspiration against a closed glottis), or the discontinuation of PPV can cause acute increases in afterload in the presence of poor LV function. Conversely, PPV with PEEP can reduce or overcome “negative inspiratory swings” in intrathoracic pressure, and by lowering the afterload, will potentially restore the haemodynamics to a more favourable position o