The primary mechanism of IMV allows which of the following?

• A. Only machine breaths
• B. Mandatory and spontaneous breathing
• C. Only bottle-fed breaths
• D. No support through the ventilator

Answer: (B)

IMV, or Intermittent Mandatory Ventilation, is a mode of mechanical ventilation that allows for a combination of mandatory breaths, which are controlled by the ventilator, and spontaneous breaths, which are initiated by the patient. This flexible approach enables patients to breathe on their own while still receiving essential support from the ventilator, making it particularly useful for patients who may have some respiratory drive but still require assistance.

The feature of combining these two types of breaths—mandatory (ventilator-delivered) and spontaneous (patient-initiated)—is why the correct answer highlights this capability. It allows clinicians to provide adequate ventilation and oxygenation while promoting patient-initiated breaths, ultimately supporting weaning from mechanical ventilation as the patient's respiratory function improves.

This mechanism is especially beneficial during the recovery phase in patients with respiratory failure, allowing them to gradually take over control of their breathing while ensuring they do not hypoventilate or experience respiratory distress.