Comparative assessment of hemodynamic changes and outcomes in ventilator weaning

Mechanical ventilation is fundamental for the management of critically ill patients. The mode of mechanical ventilation may impact the patient in different ways. This study aimed to assess the hemodynamic changes occurring when transitioning between Volume-Controlled Ventilation (VCV) to Variable Pressure Support (VPS) and VCV to Pressure Support (PS) by echocardiography. Also, a comparison between the spontaneous breathing modes in terms of outcomes, specifically, weaning of mechanical ventilation, days on a ventilator, hospital days, and survival, was conducted.

This prospective observational study was conducted on 40 mechanically ventilated patients who showed readiness for weaning from Mechanical ventilation. When transitioning between VCV and VPS in arm A and from VCV to PS in arm B, an echocardiographic assessment (transesophageal echocardiography and transthoracic echocardiography) was performed. Both modes were further compared in terms of weaning and the success of liberation from mechanical ventilation.

By comparing both arms, there was a significant difference in velocity time integral (VTI) and stroke volume (SV) for TEE and TTE with p-values of 0.044, 0.022, and 0.05, 0.059, respectively. Also, the cardiac output (CO) showed a statistically significant difference between both arms with a p-value of 0.04. On the other side, there was no statistically significant difference between both arms in terms of ventilator days (p-value of 0.88), length of stay (p-value of 0.651), weaning trial success (p-value of 0.525), and survival rate (p-value of 0.525).

The study showed that VPS is a promising modality that can be used in place of PS as a weaning mode. It provides better patient comfort and a more physiological way of breath delivery. The study also concluded that TTE and TEE will show similar results in most patients and that both can be used interchangeably.