Here at my hospital we seem to go through streaks of how we give medication to patients on ventilators. For a couple of months we might use MDI's and then we might just switch over to Nebulizers inline for a couple of months, and it is normally the same doctor who will oversee these patients on vents, it would be our pulmonologist who does it.
Tonight I just came back from being off for 2 days and we now have 3 ventilators running and all three of them are getting nebulized medications. One of the vent patients used to be getting MDI treatments but has now been switched over to nebulizer treatments. So I got to thinking which is better? Could this just be because he has Xopenex ordered as one of the medications along with Atrovent? Shouldn't be the reason we carry these by MDI also I have heard, even though I have yet to see a Xopenex MDI here at this hospital.
Doing some reading online and my own personal experience I have found different pro's and con's of using either a nebulizer or MDI with a ventilated patient, this is what I'm going to try and share with everyone, and I am looking forward to any opinions you might have for either side.
Metered Dose Inhalers Inline with a Ventilator
MDI's have to be perfectly timed with a vent cycle
MDI's give better deposition
You need more puffs from the MDI to get a regular dose to a patient due to the moisture in the ETT that will cause the medication to stick to the ETT or inspiratory limb of the vent circuit. I have seen anywhere from 4 to 24 puffs given at any one time.
MDI's treatments are faster than nebs.
Need to give a pause after the breath otherwise the majority of the medication could possible go out the exhalation limb.
You have to push the MDI right after the inhalation cycle starts or if your to early a lot of the medication goes out the exhalation side, you can actually watch this.
Nebulized medications Inline with a Ventilator
Becomes a vapor like the humidification
Do Not have to time with the ventilation cycle
Same dose as you would use with a non ventilated patient
Does take longer
Does increase measured exhaled tidal volume and minute volume
decreases the trigger sensitivity of the pressure supported breaths due to higher flow making a bigger negative pressure necessary, increasing he work of breathing in the patient
may cause problems with the internal ventilator components due to the medication sticking to the components
should possibly use a extra expiratory filter and maybe a inspiratory filter to protect the ventilator
Those are just some quick little notes of interest I have come across in my researching information for this article along with information I have learned as my time of being a RT.
Some more information I have learned about the placement of the nebulizer and MDI's when you give the treatments I have found and some I have known or used in the past.
When giving a MDI through a ventilator you should put the MDI inline as close to the wye as possible and up to 6 inches behind the wye. Always give the puff timed with a inhalation cycle or it will go down the exhalation side and not to the patient.
With the nebulizer inline I was really curious about the best way to place the nebulizer inline as to get the best treatment and from what I found which was the consensus was to put the nebulizer as far back from the wye on the inspiratory side as possible. Some even will put it behind the humidifier as they found that the aerosol of the nebulizer will mix with the humidified water aerosol, which are basically both the same. The reason it is said to place it farther back is so the inspiratory limb on exhalation will fill up with the nebulized medication aerosol and on inhalation there is a larger concentration of medication given to the patient. There is also the old law that says a gas will go towards the area with the least resistance, so if its closer to the wye the exhalation flow will be the area of least resistance due to the flow and there is a entrainment aspect to that side of the tubing also. Which makes sense to me.
I now after reading am more partial towards the use of nebulizers inline with a vent than MDI's at this time. I also will be moving my nebulizers farther back from the wye, which I will do here in about a hour's time. I lot of my questions were answered by doing some research and I hope I might of given you some more information that you never really knew.
One more thing, DON'T Forget to remove the HME before you give a treatment!!!