Critical Care Trauma Centre


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 is getting 14 guaranteed breaths per minute from the ventilator. Because these breaths are delivered by the ventilator, they are called "controlled breaths". "Assist Control" means that the patient is able to "assist" the ventilator by initiating some additional breaths, over and above the set rate.

Once the patient makes an effort to breath when in the AC mode, the ventilator detects the patient's effort, and delivers another full mechanical breath. Thus, the patient on an AC of 14 with a total breathing rate of 16 breaths per minute is triggering two additional breaths per minute, but, all 16 breaths are being delivered by the ventilator.


Image 1: A ventilator used in CCTC.





Last Reviewed: October 23, 2014