Question

A patient switched from pressure-controlled continuous mandatory ventilation (CMV) with positive end-expiratory pressure (PEEP) to pressure-controlled inverse ratio ventilation (PC-IRV) shows a good improvement in PaO2 but a decrease in tissue oxygenation. Which of the following best explains this observation?

a.High mean pressures caused by PC-IRV decreased pulmonary blood flow.
b.Intrinsic PEEP caused by PC-IRV resulted in increased alveolar recruitment.
c.High mean pressures caused by PC-IRV decreased cardiac output.
d.Intrinsic PEEP caused by PC-IRV compressed the pulmonary capillaries.

Answer 1

The switch to PC-IRV likely resulted in high mean pressures that decreased cardiac output, leading to reduced tissue oxygenation despite an improved PaO2. The correct option is c. High mean pressures caused by PC-IRV decreased cardiac output.

Step-by-step explanation:

A patient who has shown an improvement in PaO2 but a decrease in tissue oxygenation after switching from pressure-controlled continuous mandatory ventilation (CMV) with positive end-expiratory pressure (PEEP) to pressure-controlled inverse ratio ventilation (PC-IRV) is likely experiencing this due to high mean pressures caused by PC-IRV decreasing cardiac output.

The inverse ratio ventilation increases the time spent in inspiration compared to expiration, which may result in increased mean airway pressures that can impede venous return to the heart, leading to decreased cardiac output and subsequently reduced tissue perfusion and oxygenation. The correct option is c. High mean pressures caused by PC-IRV decreased cardiac output.