Clamping an ET tube?

[DartmouthDave]

Hello,

I have done some research and I have not found much information on the subject.

You have an ARDS patient (or any patient for that matter) that requires a great deal of PEEP. The patient is being transport from point A to point B on a transport ventilator. I know every time you break a circuit you lose recruited lung volume. I attended an excellent lecture in which a pig lung was ventilated and when the circuit was broken it took a long time for the lung to puff up again. I also see frequent issues when a patient is changed from their hospital ventilator to a transport ventilator (with the assumption that the transport vent is meeting the patients needs and the operators are skilled).

I have seen a few HFO patients. The ET tube is clamped if the circuit has to be broken.

I am not sure, but I think clamping of ET tube occurs in NICU for similar reasons.

So, here is my question:

Would clamping an ET prior to breaking a circuit help prevent loos of PEEP and FRC?

Thank you,

DD

[Aussieaid]

Hello,

I have done some research and I have not found much information on the subject.

You have an ARDS patient (or any patient for that matter) that requires a great deal of PEEP. The patient is being transport from point A to point B on a transport ventilator. I know every time you break a circuit you lose recruited lung volume. I attended an excellent lecture in which a pig lung was ventilated and when the circuit was broken it took a long time for the lung to puff up again. I also see frequent issues when a patient is changed from their hospital ventilator to a transport ventilator (with the assumption that the transport vent is meeting the patients needs and the operators are skilled).

I have seen a few HFO patients. The ET tube is clamped if the circuit has to be broken.

I am not sure, but I think clamping of ET tube occurs in NICU for similar reasons.

So, here is my question:

Would clamping an ET prior to breaking a circuit help prevent loos of PEEP and FRC?

Thank you,

DD

Yes this is done for that reason however you have to be certain the patient is not breathing at all on their own because if they try to take a breath while the ETT is clamped you can cause severe flash pulmonary edema. The tube is usually clamped at end inspiration as well just FYI.

[fiznat]

Interesting.. This lung recruitment volume, is it clinically significant?

[DartmouthDave]

Hello,

I have seen it done with HFO (High Frequency Oscillitory Ventilation). But, not for other patients, so far. I have a fair number of occasions in which a patient is changed from a hospital ventilator to a transport ventilator (without clamping) and things go poorly. Low volumes and high pressures and falling sats. It takes quite awhile for things to come back around.

Cheers

[tniuqs]

Have been watching this tread ... interesting.

I have operated a Bunell Jet / HFO and a Bird HFO vents in (NICU) and never have I "clamped" or occluded an ETT Tube, its NOT a common or even an advisable practice in my opinion EVER.

I don't know where you observed this Dave but no NICU I have worked would this even consider this be an option. My old NICU Director Neil Finer now a Professor NICU in San Diego would have slapped me silly if I had ever done that and I would have ended up working in housekeeping.

1- Because of the nature of ETT plastic there is a memory, one could change flow characteristics if one used Kelly's to clamp (interior lumen would become OVAL) or crimping the ETT again not advisable, but especially in HFO as this would seriously affect the entire theory of HFO. besides and there is always a "back up" conventional breath to prevent collapse of alveoli in HFO with modern NICU vents.

Even putting a thumb over the end of a ETT is folly in any paralysed patient and a huge stretch in a non-paralysed patient, as one cough and there is no high pressure blow off .. instant barotrauma.

2- IMHO this is a very poor practice, especially from one vent to another and I highly doubt from a HFO to a transport vent (maybe I read that wrong) but even if one believed that one was fast enough to do an "crimp" on inspiration occluding a tube manually,then to do an effective "inspiration hold" with an attempt to retain residual peep pressures volume ... well your actually kidding yourself.

3- If one had an ARDs patient that was that sick, and not ever in my experience ventilated with a HPO btw as a mode for ARDS (PC, PRVC and APRV yes) the current methods in treatment are varied, permissive hypercapniac ventilation, proning, perflurocarbon, but most seriously a discussion on ventilating the ARDS patient is a bit beyond this forum's readers. (no offence) if one is interested try the Respiratory Forums ... but a tad dry reading

4- OK sure Flash Pulmonary Oedema and loss of FRC and PEEP can and does occur, in fact every time one suctions and even with a closed system, so alveolar recruitment techniques can be helpful but again and most seriously if a patient is this so damn sick as to desat with a change over ... best not transport anywhere unless its to the donor table or the morgue, they are just not stable enough to be moved anywhere.

I would highly recommend if there was any delay suspected before change over vent to vent ALWAYS have a BVM/ Manuel resuscitator available and appropriate O2 flows, and PEEP set before attempting to switch vents or any movement of patient. A sad side bar I know of an incident (a highly dependant 02 patient) was moved from an aircraft to ground unit .. the vent O2 supply was not pre checked (BVM and VENT same supply) ... short story an 8 y/o kid coded and promptly died, it took less than 3 minutes.

I am open to discussion but this crimping / clamping of an ETT, but this is first time I have ever heard of this.

cheers

[DartmouthDave]

Have been watching this tread ... interesting.

I have operated a Bunell Jet / HFO and a Bird HFO vents in (NICU) and never have I "clamped" or occluded an ETT Tube, its NOT a common or even an advisable practice in my opinion EVER.

I don't know where you observed this Dave but no NICU I have worked would this even consider this be an option. My old NICU Director Neil Finer now a Professor NICU in San Diego would have slapped me silly if I had ever done that and I would have ended up working in housekeeping.

1- Because of the nature of ETT plastic there is a memory, one could change flow characteristics if one used Kelly's to clamp (interior lumen would become OVAL) or crimping the ETT again not advisable, but especially in HFO as this would seriously affect the entire theory of HFO. besides and there is always a "back up" conventional breath to prevent collapse of alveoli in HFO with modern NICU vents.

Even putting a thumb over the end of a ETT is folly in any paralysed patient and a huge stretch in a non-paralysed patient, as one cough and there is no high pressure blow off .. instant barotrauma.

2- IMHO this is a very poor practice, especially from one vent to another and I highly doubt from a HFO to a transport vent (maybe I read that wrong) but even if one believed that one was fast enough to do an "crimp" on inspiration occluding a tube manually,then to do an effective "inspiration hold" with an attempt to retain residual peep pressures volume ... well your actually kidding yourself.

3- If one had an ARDs patient that was that sick, and not ever in my experience ventilated with a HPO btw as a mode for ARDS (PC, PRVC and APRV yes) the current methods in treatment are varied, permissive hypercapniac ventilation, proning, perflurocarbon, but most seriously a discussion on ventilating the ARDS patient is a bit beyond this forum's readers. (no offence) if one is interested try the Respiratory Forums ... but a tad dry reading

4- OK sure Flash Pulmonary Oedema and loss of FRC and PEEP can and does occur, in fact every time one suctions and even with a closed system, so alveolar recruitment techniques can be helpful but again and most seriously if a patient is this so damn sick as to desat with a change over ... best not transport anywhere unless its to the donor table or the morgue, they are just not stable enough to be moved anywhere.

I would highly recommend if there was any delay suspected before change over vent to vent ALWAYS have a BVM/ Manuel resuscitator available and appropriate O2 flows, and PEEP set before attempting to switch vents or any movement of patient. A sad side bar I know of an incident (a highly dependant 02 patient) was moved from an aircraft to ground unit .. the vent O2 supply was not pre checked (BVM and VENT same supply) ... short story an 8 y/o kid coded and promptly died, it took less than 3 minutes.

I am open to discussion but this crimping / clamping of an ETT, but this is first time I have ever heard of this.

cheers

Hello,

I have never seen it until I started working at a new facility. Also, I would like to add that I have only seen it done a few times. I was wondering if other the posters had heard of the pratice.

Excellent discussion so far.

I recall a very sick ARDS patients that needed to be transfer by air ambulance. Transport time was long. When the patient was transfered from the ICU vent to an LTV1200 things went poorly. I was wondering if clamping would have helped. I guess not.

Cheers

[crotchitymedic1986]

I would also add that many patients do not do well on "transport" ventilators, and need to be bagged instead. Most services use some version of the "auto-vent" which is fine for those who are unconscious and not breathing on their own. But most patients require a "real" vent. But with that being said, I encountered several patients who did not tolerate the switch to another vent very well. I have never heard of clamping a tube.

[tniuqs]

I would also add that many patients do not do well on "transport" ventilators, and need to be bagged instead. Most services use some version of the "auto-vent" which is fine for those who are unconscious and not breathing on their own. But most patients require a "real" vent. But with that being said, I encountered several patients who did not tolerate the switch to another vent very well. I have never heard of clamping a tube.

Crotch: absolutely correct the autovent (most models) (carevent) another joke are limited to "control mode" as in a OR type ventilators so the breath rate is set / fixed, the tidal volume is set and you can suck back as hard as you want your ONLY getting what the machine rate is set for.

Some autovent / carevent have an SIMV (synchronised intermittent mandatory ventilation mode) as in Control Mode the rate / tidal volume = minute volume is fixed. If one needs another breath this does not trigger a "free" breath at volume set, the trick in looking at vents is to look for a "sensitivity knob" this is the trigger value set for "assist control" this gives a "free" breath set to the volume of the controlled breath, when setting trigger values, and higher levels of PEEP well this can be problematic with auto cycle issues but I digress.

The trick in Ventilating Patients that are awake is take their drive away (PaCO2) and keep them flat.

SIMV allows the circuit to be "opened" and allow a breath from the base line or set PEEP .. a very old mode was used for weaning patients in the past but a crappy "Transport mode" unless a very stable long term patient ... SIMV will do some magic time window tracking so that it does NOT deliver the set breath when the patient has taken a breath from baseline (its a bit more complex but thats the idea in a nutshell) oddly enough from a nut !

Dave: The LTV is a awesome piece of kit and my choice for dang near every transport, the LTV (Lap Top Ventilator series) is a true ICU ventilator and is capable of ventilating most ARDS type patients (generally speaking) a great selection of modes, but the thing is sometimes the ARDS patients do not cooperate and die no matter how they are ventilated. Out of about 60 different Ventilators models that I have used on patients or bench tested this LTV is one of the best, although one has to fiddle with the pre programmed values for Ti% sometimes called slope for NIPPV that's a bit of a PITA.

Honestly the best way to understand all these magic modes is put a mouth piece on a circuit and TRY breathing on them ... nothing like first hand experience.

I will reiterate that clamping or crimping an ETT no matter what "therory" is ill advised by myself.

cheers

[Aussieaid]

You're completely entitled to your opinion Squint and I respect the fact that this is a procedure that you may not be comfortable doing. I also understand that it is not generally used in neonates and I would never use it on one myself. I think their lungs are too fragile and they are infrequently paralyzed even on the HFOV or Jet ventilation.

However... you may not have heard of it but it is done in certain situations to prevent lung de-recruitment. It is not a benign procedure and certain conditions need to be met. The patient cannot be breathing spontaneously, the clamp has to be well padded with either plastic or rubber tubing or gauze so as not to damage the ETT and you have to be cautious that there is no breath stacking which could cause barotrauma when you unclamp again.

It is not a common procedure but it is more widespread than you realize. It is most frequently used with HFOV but can be used with regular ventilation when the pt is on high levels of PEEP and does not tolerate the loss of lung recruitment. It was ordered by the Intensivists in my old unit. I don't advocate that it be used lightly but I have used it in the transport environment when I have had a sick respiratory patient with good effect. As long as you prevent any breath stacking and the patient has no spontaneous respirations then all you are doing in effect is doing an inspiratory hold procedure. It takes no more than a second or two if you have everything properly set up to do it. It is not without risk as I said.

The whole concept behind Critical Care Transport is to transport critically ill patients to a higher level of care (generally). It is not in the best interests of the patient to leave them in a facility that is not equipped or educated to deal with certain patient populations. That necessitates transporting patients who may not be as stable as you would ideally like them to be. It is also not in their best interests when you do have to take them into a less controlled environment such as transport to not optimize their condition as best you can to allow them to deal with the added stress. Such as loss of lung recruitment in a pt that does not tolerate it very well. Then you compound the problem by having to take them to altitude and add numerous other stressors on them as well.

One other problem with many companies in the transport world (except some specialty teams) is the fact that we only have self inflating bags (with added PEEP valves) and these are way less than ideal for use with critically ill respiratory patients. I will take the flow-inflating bag from the sending hospital but you do have to be trained in their use so it is not something I would recommend unless someone has that training. However when possible I prefer to maintain them on the ventilator and only have it available for emergency use.

Unfortunately I do not have any literature on any kind of study performed re clamping the ETT but you can find numerous references to it in various powerpoints and other studies.

Basically if someone is not comfortable doing it and really do not know what they are doing with the procedure I also wouldn't recommend it. However I will reiterate that it is done and it is done to prevent loss of lung recruitment.

Cheers!

Edited January 16, 2011 by Aussieaid

[1EMT-P]

I have been working in both critical care transport & ICU since the early 90's & I have never once read anything about or ever seen anyone clamp an ET tube. I personally would not recommend clamping an ET tube in a critically ill patient without knowing the rationale & without having a Physician's order.