I have said before (the post right before yours and my post before that)PS is not perfect at overcoming the RAW of the ETT but given the choice of NO PS at Phigh or low levels of PS at Phigh I will choice low levels of PS because I can overcome some of the Raw of the ETT vs NONE with no PS. Once again I would like to point out that ATC IS A BETTER OPTION THAN PS, but what do you do if you do not have ATC (No one has answered this one yet)?
Our poster that we are presenting is showing that the Low levels of PS are not seen at the bottom mof the ETT, like some have proposed. Not PS better than ATC.
Thankyou for the article, I will find it and read it.
I just found another poster presentation of ATC and PS in APRV that was presented at the Critical Care Medicine Congress in January of 2006. It found that ATC at the initiation of Phigh increased the carinal pressure higher than the set Phigh, interesting. It then showed that the PS on spontaneous breaths also increased carinal pressures, interesting aswell. The first of the two statements makes sense to me as a Drager user becasue I have seen the chest spike up on the initiation of Phigh with ATC(Drager evita was used in poster experiment). The later took me back a bit (considering what we are seeing)unitl I read what levels of PS they were testing (10-20 cmH2O), that is ignorant to me. Why would you put that much PS ontop of Phigh in Bivent on the Servoi? At this point I wonder if they were trying to make their numbers increase, instead of using normal levels of PS.
I'm a GE rep but feel free to read on if you like. If your interested in seeing the effects of tube resistance on vent pressures first hand then why not check out the Engstrom ventilator. With real time tracheal pressure measurements it gives you an excellent view of pressures minus the tube resistance. It's simple, quick and a great teaching tool.
How are you getting the "real time tracheal pressures" with your vent?
I found the article you refered to and I agree. I have never said that PS is perfect at overcoming the Raw of the ETT. The article is correct!
But what I ask again is:
What is a Servoi user supposed to do to overcome the Raw associated with the ETT?
We have a fleet of Evita 2's and we don't utilize ATC with APRV because our docs don't like to added pressure seen on the pressure waveform (don't get me started there). APRV with no ATC and are patient's wob is fine; how do I know this? Because I can ask them due to minimal sedation requirements. It's all about reestablishing lung volume.
The WOB you talk about is percieved WOB, these patients do have some sedation on board so they are not going to percieve things aswell as they might otherwise. But WOB is just that the amount of work (joules) it takes to breath. Yes APRV is about reestablishing lung volumes, but right now you have a normal FRC and if you put a ETT in your mouth and walked around breathing through it all day your WOB is higher than what it would be without it in even though you have a normal FRC. Patients that are on APRV or for that matter on a vent in general do not need to be extending work to anyother areas that do not have too. That is one of the reasons we put patients on active humidifiers is so that they do not have to spend and lose energy heating the gas we give them. Could they do it without us YES, but at what expense.
I had a patient in the ER that had a open femur fracture, compound ankle fracture as well as right hip fracture. When I asked him to rate his pain he said it was a 3, this man had not had any pain meds yet. Does this mean that he was not in pain or due to shock he was unable to percieve the pain correctly?
ATC or low levels of PS should be used in my opinion with APRV.This message has been edited. Last edited by: light,
Hi. I found the article you are mentioning and if I may I will paste it here so you can get it and read it.
Sorry to intrude, but I was sent a link to this forum by an RCP educator friend of mine. I'm a pediatric critical care physician and pulmonary researcher, and I must quickly (I don't have time to exhaustively explain right now) make one point:
WORK OF BREATHING and OXYGEN COST OF BREATHING ARE NOT HIGHER WITH AN ETT IN PLACE. That is a silly myth that is widely propagated. You do not need any PS to overcome the "resistance of the artificial airway". When measured, even in children, WOB with an ETT is LOWER than without, likely due to better laminar flow when compared to a native airway with its inherent obstructions. I promise I'm not just talking - we measured it, as have others. See ref Willis BC, Intens Care MEd, 2005, "Pressure rate products...&c". So don't worry about PS on top of Phigh or ATC or any other such silliness!
I can discuss more later if this creates the typical firestorm of denials and dogma-clinging it usually does.
But PS is not about decreasing the WOB percieved or otherwise. It is about augmenting, a more than likely, sedated patients spontanous breathing effort. It is about resting their lungs while at the same time giving back at least some of the work to the patient. Regardless, is the previous poster suggesting that we add nothing to a patient's spont. breating effort? Does not seem like a very good weening strategy to me.
This makes no sense to me. WOB with an ETT is LOWER than without? Sir have you every been intubated? I have and trust me there is increased WOB!! Is not the ETT itself an Obstruction?