Low Tidal Volume Alarm

Specialties MICU

Published

Hi

I am a new nurse in the ICU and am still getting use to working with vents. The other day I had a fully vented pt whose low tidal volume alarm kept going off. I auscultated for an air leak around his ET and didn't hear one. One of the other nurses came by and told me that low tidal volume alarms usually meant that the pt is fighting the vent and told me just to increase his sedation. Is this true? The pt was not breathing over the vent, the peak pressure alarm was not alarming, and the pt did not seem like he was agitated or anxious at all. In fact he was just laying in bed with his eyes closed and not following any commands or even moving. I felt weird going up on his sedation when he already seemed like he was pretty sedated :/

I would think positional ET tube (AC mode where vent delivers set volume but pt not getting that volume d/t air leaking around ET tube. If its pressure control vent, suction pt. low volume could be related to high pressures being reached before large volume could be delivered

What was your mve? What mode of ventilation were you on prvc? Simv?

Specializes in ICU/CCU/CVICU.

Yeah we need more info. What type of ventilation mode was the pt on? What sedation were they on and what tiler score were they?

Low TV is usually:

Air leak from cuff or malpositioned tube

Spontaneous breathing mode and pt isn't pulling good volumes

Pt biting tube; a recalculation of TV on the vent will cause it to trigger a low TV alarm if they're biting the tube

Leak in system, either an O2 disconnect or some other connection between the ETT and vent

Pt was on Assist Control and on a Fent drip @ 50 with Ativan pushes PRN. I was just confused since I wouldn't think low tidal volume by itself would be an indication the pt was fighting the vent. I always though there would be other sings like physical signs of agitation and the peak pressure alarm.

Usual causes: ett cuff leak (you hear it), biting ett (you see it), leak in circuit (check connections), or patient it's breathing enough volume (usually on awake patient or weaning mode).

This is where you also need to look at the graphics along with the patient. The waveform will tell you alot more. Sometimes the patient's breath and the ventilator are just a little out of synch. Sometimes the flow is too low and the patient wants a quicker breath.

You also need to see where the alarms are set. There may have been a vent change made and the alarms were not adjusted to reflect the new changes. This often happens when too many people are allowed to make changes on the ventilator or the RT is too busy answering multiple calls at one time and gets distracted.

Either way it would be good to have an RT review the ventilator with you. Get into a habit of looking at the alarms at the beginning of your shift and go over the settings (all of them) with the RT. Checking the baseline together will help you make more sense of things throughout the shift. Reviewing what meds you have to keep the patient comfortable with the RN will also help in the weaning or stabilization process.

Specializes in MICU, SICU, CICU.

Pt may need to be suctioned

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