Certified Transport Registered Nurse Certification Practice Exam

What must be monitored in Assist Control (AC) mode to avoid breath stacking?

1. Peak fall pressure

2. Minute ventilation and pressure alarms

3. Respiratory rate only

4. Oxygen saturation levels

The correct answer is: Minute ventilation and pressure alarms

In Assist Control (AC) mode, it is crucial to monitor minute ventilation and pressure alarms to avoid breath stacking. This mode of ventilation is designed to provide a set number of breaths, but it also allows the patient to initiate additional breaths. If the patient is taking extra breaths in between the mandatory breaths provided by the ventilator, it can lead to breath stacking, where breaths overlap without complete exhalation. Minute ventilation, which is the total volume of gas inhaled or exhaled from a person's lungs per minute, needs to be closely monitored because an increase in spontaneous breaths can significantly raise this value. If minute ventilation becomes excessive, it can indicate that the patient is attempting to breathe more than the number of ventilator-assured breaths, leading to inadequate time for full exhalation. Additionally, monitoring pressure alarms is essential because they help identify situations where pressure might build up during the breath stacking, potentially causing barotrauma or ventilation-related injuries to the patient’s lungs. High airway pressures can signify that the set tidal volume is not being adequately delivered due to insufficient exhalation time. Together, monitoring these two parameters allows healthcare providers to adjust ventilator settings, ensuring effective ventilation while avoiding complications like breath stacking.