Head Injury and Hyperventilation

brainkandy87 · May 27, 2012

I haven't had much experience with this topic so I'll hold any opinion, but it made me starting researching and I found a couple of good studies...

http://www.safar.pitt.edu/content/grant/jc/2007/0202%20Alexander.pdf

Aliakey · May 27, 2012

In our EMS, hyperventilation is a big no-no. I know what you mean about it being a practice in the past, but thankfully we don't see it anymore unless we have an outside first responder who's a bit nervous and bagging too fast --- a kind reminder takes care of that. The ResQPods we use for cardiac arrests have the timing light on them (10 breaths a minute), and helps with the nervous EMT student, etc. to keep them on track along with human coaching (inspiratory/expiratory ratio, watch the volume, etc.).

Still run into some old school folks outside the area... hopefully, those required case reviews will address the last stragglers. Hadn't seen any problems with ED nurses in our level 1 and level 2's... they got it down

Esme12, ASN, BSN, RN · May 28, 2012

I don't think the hyperventilation is "intentional" these days. At the scenes of many accidents/trauma the medic/flight crew are assisted by firefighters and other personnel as well as the adrenaline pumping from an extended extraction. From many emergency departments is where the patient is constantly being transported from department to department....especially from outlying ED centers where there is extensive travel done for CT scanner etc.....and they need to bagged trough the entire scan....is what leads to the patient being more hyperventilated.

It's kind of the nature of the beast.....sometimes

hiddencatRN, BSN, RN · May 31, 2012

I've seen it done in our ED, but only when it appears that herniation is imminent and they're just trying to keep the brain together while transporting the patient to the OR. Otherwise it's not our standard practice.

NO50FRANNY · Jun 2, 2012

Thankyou all for your replies, it seems that our facility doesn't differ that greatly from others. I am thinking I will put together an observational study to note the rates from Ambulance crews and Emergency department clinicians when bagging only. Then this could be correlated with ABG's, focal signs and outcomes. I am a little obsessed with TBI at the moment. Any ideas you have feel free to add. Once again thankyou for posting.

Candyn · Jul 8, 2012

I have questions.

Why do we not want to hyperventilate a TBI patient?

And when you said "I've seen it done in our ED, but only when it appears that herniation is imminent and they're just trying to keep the brain together while transporting the patient to the OR." Does that mean it is ok to hyperventilate if they have imminent herniation? Why is that?

Esme12, ASN, BSN, RN · Jul 8, 2012

I have questions.
Why do we not want to hyperventilate a TBI patient?
And when you said "I've seen it done in our ED, but only when it appears that herniation is imminent and they're just trying to keep the brain together while transporting the patient to the OR." Does that mean it is ok to hyperventilate if they have imminent herniation? Why is that?

Hyperventilation lowers intracranial pressure (ICP) by the induction of cerebral vasoconstriction with a subsequent decrease in cerebral blood volume. The downside of hyperventilation, however, is that cerebral vasoconstriction may decrease cerebral blood flow to ischemic levels.

"Modulation of Paco₂ has been used for > 40 years,¹ first in neuroanesthesia and subsequently also in neuro-intensive care. Preliminary work has shown that the volume of the swollen brain could be decreased by lowering Paco₂. With the realization that raised intracranial pressure (ICP) is a significant, treatable problem in patients with traumatic brain injury (TBI), hyperventilation became a cornerstone in the management of TBI and has remained so for decades. Hyperventilation lowers ICP by the induction of cerebral vasoconstriction with a subsequent decrease in cerebral blood volume."

^{Hyperventilation in Head Injury*}

^{interesting thread....https://allnurses.com/neuro-intensive-care/carbon-dioxide-icp-711160.html}

NO50FRANNY · Jul 9, 2012

I have questions.
Why do we not want to hyperventilate a TBI patient?
And when you said "I've seen it done in our ED, but only when it appears that herniation is imminent and they're just trying to keep the brain together while transporting the patient to the OR." Does that mean it is ok to hyperventilate if they have imminent herniation? Why is that?

Hi there, most of the recent observational / clinical research shows that we shouldn't hyperventilate in cases of TBI for the reasons outlined by Esme12. The theoretical benefits described are the reason it used to be standard practise which is why some clinicians still do it. Hyperventilation compromises cerebral oxidative metabolism, can actually cause cerebral ishchaemia and worsen cerebral oedema, and most international guidelines advise against it. The move these days is toward aiming for a therapeutic PCO2 (in fact, normal to mild hypercapnoia), optimising cerebral blood flow and using other methods to lower ICP, such as definitive surgical management or IV administration of hypertonic solutions such as hypertonic saline or mannitol. "If ICP increases to equal MAP, CPP becomes zero, resulting in complete brain ishchaemia and brain death"(Merck). Anectodally, women tend to be on the receiving end of "over" ventilating for obvious reasons. To answer your question, if the patient is herniating, they are about to die, so I guess hyperventilating can be considered a "last ditch effort" because it may be felt that we can't really make it worse. So, if definitive management is an hour away, then it could be considered an option.

To give you an example, recently, we had a 60yr old lady who was hit by a cyclist, thrown backwards and sustained a large subdural. She had a prolonged loss of consciousness at scene and was GCS 14 when she arrived in ED. She remained GCS 14 for an hour or so and was about to be taken to theatre. She then (in the space of 10 minutes) dropped her GCS to 4, developed an ovoid pupil and was intubated. Neurosurg ordered mannitol and the senior ED physician hyperventilated her on the way to OT (keeping her brain together while transporting to OT). If there are focal signs of herniation such as ovoid pupils / pupillary changes, loss of reaction to light, bradycardia, decerebrate / decorticate posturing, hemiparesis, rapidly deteriorating GCS, most of our pre-hospital and ED physicians will just bag (but just at a normal rate) and may administer a dose of a hypertonic solution and rush to definitve management if possible.

Candyn · Jul 10, 2012

Thank a lot for response. I always find the brain to be very insteresting and difficult to understand.

Just to clarifiy. Hyperventilation causes vasoconstriction and then ischemic. CO2 causes vasodilation thus increase blood flow to brain?

TRUtraumaRN · Jul 11, 2012

I was reading about this the other day cause it seems to be a hot topic in current treatment of TBI's. The Guidelines for Management of Severe Traumatic Brain Injury do not recommend prophylactic hyperventilation (PaCO2 less than 25 mm Hg). Keep the PaCO2 between 30 and 35 mm Hg for the first 24 hours. If hyperventilation is being used, recommendations suggest measuring cerebral oxygenation (SjO2, PbrO2...). A quick simple way to measure effectiveness of ventilations without an ABG is ETCO2 monitoring. Current therapy recommends keeping ETCO2 35-40 mm Hg. Levels below 35 should be avoided; however, in some instances (evidence of herniation or acute neuro deterioration) it is fine to hyperventilate with a goal of maintaining an ETCO2 30-35 mm Hg and discontinue when signs of herniation are alleviated.

Hope this helps a little.

Sarah22P · Jul 11, 2012

anectodally, women tend to be on the receiving end of "over" ventilating for obvious reasons.
/quote]
i am not sure what the obvious reasons are? what am i missing? otherwise very helpful information.