Volume-controlled Continuous Mandatory Ventilation (CMV)

CMV: Continuous Mandatory Ventilation

  • Volume Controlled …but it can be pressure-controlled
  • Time-Triggered
  • Volume- limited OR Pressure-limited, Flow-limited (but doesn’t have to be flow-limited)
  • Time-Cycled (but it can be volume-cycled if you don’t want inspiratory pauses)

The key feature is, its MANDATORY, time triggered and time cycled, and it ignores attempts to breathe.

The volume-controlled CMV gives you optimal control over your minute volume. If you are trying to maintain a very narrow CO2 range in a paralysed sedated head injury patient, this would be a good choice.

Of course, if they wake up, they will start fighting the ventilator, coughing and sucking weirdly against it, as it obstinately blows unwanted breaths into their lungs.

It is an uncomfortable mode of ventilation for anyone who is even slightly awake.

References

Most of this information comes from only two textbooks. With "Basic Assessment and Support in Intensive Care" by Gomersall et al (as well as whatever I picked up during the BASIC course) as a foundation, I built using the humongous and canonical "Principles and Practice of Mechanical Ventilation" by Tobins et al – the 1442 page 2nd edition.

Jonson B, Beydon L, Brauer K et al. Mechanics of respiratory system in healthy anesthetized humans with emphasis on viscoelastic properties. J Appl Physiol 1993; 75 : 132–40.

Zavala, Elizabeth et al.Effect of Inverse I: E Ratio Ventilation on Pulmonary Gas Exchange in Acute Respiratory Distress Syndrome Anesthesiology: January 1998 - Volume 88 - Issue 1 - p 35–42