Hyperventilation indications

[adwilcox28]

When is hyperventilation appropriate or even needed?

 

[MMiz]

When is hyperventilation appropriate or even needed?

In recent years I can't think of any reason to hyperventilate a patient in the pre-hospital settings.

 

[adwilcox28]

what about in respiratory acidosis?

 

[Shishkabob]

what about in respiratory acidosis?

How do you know they don't have metabolic acidosis they are trying to compensate for?

 

[vquintessence]

what about in respiratory acidosis?

How are you coming to that conclusion? Based on bradypnea w/ hypercapnea?

What is the etiology behind those symptoms? Is it CNS insult, or drugs, or pulmonary pathways?

Sorry to answer your question w/ more questions, but a yes or no blanket statement doesn't apply

 

[Smash]

Things like DKA or ASA toxicity may require hyperventilation to try and keep pH at an acceptable level. They will be breathing hard and fast by themselves to blow off as much acid as they can. If we then intubate them and don't keep their EtCO2 at least as low as it was pre-intubation they will quickly die.

There may also be a theoretical benefit in hyperventilating the tricyclic antidepressant overdose patient to assist with causing alkalosis, although sodium bicarbonate is the treatment of choice and the evidence for hyperventilation is scarce.

It's not recommended for traumatic brain injury anymore.

 

[Veneficus]

It's not recommended for traumatic brain injury anymore.

In the prehospital setting.

A handful of trauma srgeons I know try to reserve the transient effects for themselves and anesthesia.

 

[truetiger]

What about when SHTF and your head injury pt is herniating with a HR in the 20's? This happened to me once in CT and the ER doc immediately ordered hyperventilation + .5 of atropine. Would this be an exception to the pre-hospital rule?

 

[Veneficus]

What about when SHTF and your head injury pt is herniating with a HR in the 20's? This happened to me once in CT and the ER doc immediately ordered hyperventilation + .5 of atropine. Would this be an exception to the pre-hospital rule?

In medicine there are exceptions to every rule.

The big problem with EMS is they don't know when the exceptions are usually. Nearly every patient with some variable mechanism is suspicious as "really bad" and as soon as somebody sees a few CCs of blood or some similar finding that suspicion is confirmed. It gets even more complicated in multisystem trauma. Where the therapies actually oppose each other and a happy medium must be found.

Because the effect of hyperventilation is transient, it is unlikely going to last long enough from the field to get to the ED.

From that point they still have to be evaluated, and neurosurg or a rather ambitious CC surgeon is going to have to make the call and relieve the pressure surgically.

If they were herniating when you found them and you used the transient therapy, how bad are they going to be before somebody who can fix it can help?

The use of hyperventilation should be used in the hallway/elevator on the way to surgery. Not before.

I agree with the actions of the ED doc you described. But look at where he is. In the hospital.

 

[truetiger]

I 100% agree that the pt in this situation is SOL and understand the benefits may be minimal, but when the pt decides to crash enroute would it hurt to try?

 

[usafmedic45]

what about in respiratory acidosis?

Are you doing blood gases in the field?

Things like DKA or ASA toxicity may require hyperventilation to try and keep pH at an acceptable level.

You know how hard that is to do with mechanical ventilation when you can't accurately control the tidal volume, I:E ratio, etc?

There may also be a theoretical benefit in hyperventilating the tricyclic antidepressant overdose patient to assist with causing alkalosis, although sodium bicarbonate is the treatment of choice and the evidence for hyperventilation is scarce.

Scarce? I've never seen any evidence for it.

 

[medicRob]

Are you doing blood gases in the field?

I was just about to ask if his service was using an iStat in the rig and for an application to that service.

 

[Smash]

You know how hard that is to do with mechanical ventilation when you can't accurately control the tidal volume, I:E ratio, etc?

Yes. Your point being?

Scarce? I've never seen any evidence for it.

Both Kingston (1979) and Bessen (1985) found benefit in hyperventilating TCA overdose, however more recently McCabe (1998) found little benefit when compared with NaHCO3 or hypertonic saline, whilst Wrenn (1992) found that in some cases the alkalosis when hyperventilation and NaHCO3 was combined may actually worsen outcomes. Goldfranks Toxicologic Emergencies (9th ed) discusses hyperventilation in it's chapter on cyclic antidepressant toxicity.

 

[usafmedic45]

Yes. Your point being?

Ventilating someone with sufficient minute ventilation to do anything in DKA is going to put the patient at excessively high risk of a pneumo if you're not really careful. That's my point.

McCabe

You mean the pig study that originally pointed out that it likely is the sodium and not the alkalosis that is beneficial?

The Wrenn and Slovis paper is my main evidence that unmonitored hyperventilation (read as: most of what happens in the field) is probably detrimental rather than benefiical in TCA OD.

 

[8jimi8]

Ventilating someone with sufficient minute ventilation to do anything in DKA is going to put the patient at excessively high risk of a pneumo if you're not really careful. That's my point.

what about using a pedi bag ?

 

[Akulahawk]

Using a pedi bag possibly won't deliver the tidal volume needed to exchange enough air, and you'd have to increase your rate over a standard adult bag even if it does. However, absent stacking if the I:E ratio is OK at that rate, the pedi bag would certainly likely prevent barotrauma because of the limited volume per breath you can get with it. I'd be concerned that because of the limited volume, you'd be tempted to go as fast as you can, which could lead to stacking... which could lead to barotrauma.

Good thinking though.

At this point, in the field, I don't see much indication for hyperventilation. I really don't especially because most of us won't be able control rate, depth, I:E ratio manually.

 

[colorado207]

I'm kind of worried about this for the registry test.. the book we are currently using (2010 Prehosp Emergency Care Brady) recommends hyperventilating head injured pts. @ 20, however our instructors say that now hyperventilation is never indicated, and that in fact it can be very harmful.... something along these lines:
http://www.otwo.com/pdf/articles/In...we squeezing the life out of our patients.pdf
Anyone see any questions on the national registry tests that give you "hyperventilate head injured pt 20 bpm" as a possible answer?