CMV or AC Ventilation


Assist Control (or "AC") is a term used to describe the number of breaths a patient is receiving from the breathing machine (ventilator). AC refers to a specific method for giving the patient mechanical breaths. An "AC of 14" means that the patient's breathing is fully supported.  The "14" is the number of guaranteed breaths.  If the patient tries to take any extra breaths, each effort will result in another full mechanical breaths.

Different brands of ventilators have different names or features for providing full breathing support.  Continuous Mandatory Ventilation (CMV) is another way to describe mechanical ventilation where all of the patient's breaths are being provided by the ventilator.  You may see "CMV" on the ventilator when a patient is receiving full support and care provider's may refer to this as "AC".  They terms generally mean the same thing.


Last Reviewed: November 13, 2018