Which of the following characteristics is NOT used to determine the mode of ventilation?

• A. Breath type
• B. Patient's age
• C. Targeted control variable
• D. Timing of breath delivery

Answer: (B)

The determination of the mode of ventilation is primarily focused on how breaths are delivered to the patient, which involves several specific factors like breath type, targeted control variable, and timing of breath delivery.

Breath type refers to whether the breaths are mandatory (delivered by the ventilator) or spontaneous (initiated by the patient). This characteristic helps to establish whether the mode is, for example, assist-control or pressure support.

The targeted control variable is critical in dictating how the ventilator responds to the patient's needs, such as controlling pressure, volume, or flow during mechanical breaths. This influences the choice of mode based on the clinical objectives and the patient's condition.

Timing of breath delivery plays a role in defining whether the ventilator operates in a synchronous mode with the patient's respiratory efforts or uses a timed approach to deliver breaths at specific intervals.

In contrast, while a patient’s age may impact clinical decisions and considerations in overall management, it is not a characteristic directly used to determine the mode of ventilation. Instead, modes are primarily based on respiratory mechanics, patient-ventilator interaction, and the underlying pathology being treated. Thus, age does not influence the fundamental selection of ventilatory mode.