Intermittent Mandatory Ventilation

IMV

RC 270

IMV is a technique which allows the patient to breathe spontaneously (setting his own Vt and rate) with supplemental O2 and to periodically get a specific number of positive pressure breaths from the ventilator.

Its like being on a T-tube and the ventilator at the same time

Ex. #1 : IMV of 8, Vt=900 ml

Eight times a minute the patient gets a 900 ml positive pressure breath from the ventilator. In between the positive pressure breaths, he breathes spontaneously at his own rate and Vt.

Indications/Advantages for IMV

Weaning– Using IMV to wean is no faster or better than

classical weaning or any other mode Controlling PaCO2

– IMV Ve is titrated with patient’s spontaneous Ve

– Often done with neuro patients To get a lower mean intrathoracic pressure

than A/C

Most ventilators incorporate a demand system for IMV that allows the patient access to source gas at the rate, flow, and volume, that the patient demands.

INITIATING IMV

If starting with IMV, set IMV Ve as you would back-up Ve for A/C

If switching to IMV from A/C, set IMV Ve to about one half of the patient’s OBSERVED Ve when he was on A/C

Titrate IMV Ve based on ABGs and patient’s spontaneous Ve