What is mmv with v being ventilation?

Answer 1

MMV stands for Mandatory Minute Ventilation. It is a derivative IMV (Intermittent Mandatory Ventilation). "with V" refers to the option to vent in this mode using volume as a set target rather than pressure.

The term "Mandatory Minute Ventilation" is just that; the user sets a minimum target minute volume (MV) by setting the rate (f) and Vt (tidal volume). The ventilator will then guarantee that the patient receives AT LEAST this predetermined MV. If the patient is doing no spontaneous breathing, the vent recognizes this and will provide full support for the patient, giving them that set MV. As the patient begins to breathe more on their own, the vent also recognizes this and will begin taking away mechanical breaths, allowing the patient to perform the work necessary to achieve the set MV.

Like SIMV w/ volume, in MMV, spontaneous breathing can be supported with pressure support (PS). UNLIKE SIMV, however (and as stated above), as the patient begins to breathe more on their own, the vent will provide fewer and fewer mechanical breaths providing that the patient is reaching at least the predetermined set MV.

This mode is a good choice for rapid weans, such as post-op patients, because as the patient begins to wake, the vent challenges the patient to maintain adequate ventilation on their own. The "mandatory MV" provides a safety net so that if the patient becomes more sleepy or begins to fatigue, the vent will recognize this and add support. This mode provides a less time consuming and controlled method of rapid weaning.

Important to note is that although this mode will guarantee that a minimum MV is reached, the vent user still must monitor the patient for signs of distress and respiratory fatigue. Spontaneous, rapid shallow breathing, for instance, may achieve your set MV, but achieving a MV with very small Vts and high rate is obviously not suitable for extubation.