Vent pt with increased TV cause of increased PIP?

nutella, MSN, RN · Nov 18, 2016

Perhaps this page can help you out in understanding some basics:

Nurse Nightingale: Ventilators Explained Extremely Easy

and check out this presentation as well:

http://www.ucdenver.edu/academics/colleges/medicalschool/departments/surgery/education/GrandRounds/Documents/GRpdfs/2008-2009/8-04-08%20McIntyre.pdf

Of course the PIP depends on several things. Generally speaking, if you have a pediatric patient who is still growing, the settings probably need an adjustment once in a while just based on the fact that the person is still growing. But you also do not want too much constant pressure or peak pressures to avoid ventilator associated damage.

When you increase the volume to be delivered, the pressure may be higher because you expand the lungs more so to speak - there can be more resistance. With the SIMV setting your patients can breath on her own between the mandatory ventilations. But for example, if your patients gets exhausted from exercising breathing muscles or just tires out or asleep deeply and "forgets" to breath the machine will just deliver the ventilation reliably.

You have the max pressure that is tolerated for this patient, and that is often reached when there is more resistance due to mucus build up/ plugs so your thoughts are right to check for any obstruction first if the peak pressure is reached or you are seeing an increase. I assume you got training and know how to intervene as you are alone with a vent patient.

My suggestion is to always check when you take over that you have the bag and mask / bag connector close to the patient and that it is working correctly and that the suction is working (switch it on and check to see if it actually suctions) and that you have suction catheters and other supplies available and ready. Make sure you know what to do in case there is a power outage (winter is coming....), that you have back up oxygen in case you have to manually vent the patient. Make sure that you always check the track is secured ok when you come on, that the trach band is tight enough but not too tight, that the canula is in ok, that you have an extra canula or inner canula (depends on what trach it actually is) and that you know what to do in case the trach becomes dislodged.

melissarai · Nov 18, 2016

Thank you for your response and the resources, they have helped :)

A lot of what you discussed is what I was thinking and it was good to confirm I am understanding and on the right track. I feel confident in suctioning and changing the trach, and we fit and change the trach ties each time we come on shift. Ambubag is kept at bedside, one thing I've wondered is where the vent helps breath, at what point would you disconnect from vent and bag the pt if the vent is on and functioning properly?

Wile E Coyote, ASN, RN · Nov 18, 2016

I speculate that if you watch the patient's resp pattern during the high PIP periods, you'll see periods where the patient's expiratory period doesn't jive with the vent's expiratory period.

Look up 'breath stacking' and 'auto-peep' and see if that matches what you're seeing.

Increasing the TV alone without compensating by adjusting the inspiratory time, I/E ratio, inflow time, etc. for the machine breaths (vs spont breaths) can increase the peak pressures. (although that's predominantly seen by only increasing the rate in mandatory rate modes like A/C, aka CMV)

Midazzled · Nov 18, 2016

Medscape has an excellent, easy to read article that pops up when you type "SIMV" into google. I would add that to your list to read in your time off.

Ventilators can be very confusing at first, but you will get past that with reading and practice, after which they won't intimidate you so much.

heinz57 · Nov 19, 2016

How many kg does the child weigh?

Has the child has a recent CXR?

Increase secretions prior to change?

Cuffed or cuffless trach?

PMV trials?

Reason for the ventilator?

People often get confused with the SIMV mode believing it is the only mode which allows for spontaneous breathing. Almost every modern ventilator allows for spontaneous breathing. SIMV can be very uncomfortable if the pressure supported breath is inadequate. SIMV also has a "mandatory rate". If the patient is not breathing, all breaths are mandatory.