CHEST Guidelines-Cardiogenic-Auto-Triggering-as-a-Consequence-of-He

Cardiogenic-Auto-Triggering-as-a-Consequence-of-He

Pdf Summary

A 70-year-old woman with a history of heart failure presented with hemorrhagic shock due to hemoperitoneum after a paracentesis. On the third day of hospitalization, she experienced respiratory alkalosis and increased respiratory rates on the ventilator in the absence of spontaneous inspiratory effort. Switching to a pressure support mode revealed that cardiogenic oscillatory flow was auto-triggering the ventilator. This was resolved with a large-volume paracentesis. Cardiogenic auto-triggering can lead to patient-ventilator dyssynchrony, respiratory alkalosis, lung distension, and difficulties in weaning from the ventilator, yet may go unrecognized in ICUs.<br /><br />Auto-triggering occurs when unintended breaths are triggered without patient effort, due to factors like circuit issues or cardiogenic oscillations. This can exacerbate sedation use, extend the duration of mechanical ventilation, and result in worse survival rates and prolonged hospital stays. Cardiogenic pulmonary flow oscillations were first noted in 1942 and occur due to changes in intracardiac volume affecting intrathoracic pressure. These oscillations can exceed ventilator flow-trigger thresholds, leading to involuntary breath delivery.<br /><br />Studies have found that cardiogenic auto-triggering frequently occurs in patients with brain death, hyperdynamic hemodynamic profiles, or after cardiac surgery. The phenomenon is often due to increased cardiac output and ventricle pressures. In the case reported, the auto-triggering was attributed to changes in thoracic pressure due to hemoperitoneum, which were corrected by adjusting the ventilator settings or addressing the underlying physiological changes.<br /><br />Clinicians are advised to consider cardiogenic auto-triggering in ventilator-dependent patients with unexplained respiratory alkalosis. Adjustments such as increasing the flow-trigger threshold or switching to pressure-triggering may help in cases of ventilator auto-triggering.

Keywords

cardiogenic auto-triggering

ventilator dyssynchrony

respiratory alkalosis

hemoperitoneum

mechanical ventilation

cardiogenic oscillations

pressure support mode

intrathoracic pressure

patient-ventilator interaction

ICU management