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Hypoxic Drive

Printed From: First Aid Cafe
Category: Mainly First Aid
Forum Name: General Questions
Forum Discription: If it does not fit elsewhere put it here!
URL: http://www.FirstAidCafe.co.uk/Forum/forum_posts.asp?TID=5153
Printed Date: 18 Apr 2014 at 2:44pm


Topic: Hypoxic Drive
Posted By: Firestreak
Subject: Hypoxic Drive
Date Posted: 26 May 2008 at 7:32pm
 Does anyone have an accurate but simple description of Hypoxic Drive please?
I'm updating a presentation used during training of Community Responders and am looking for something descriptive - with a bit of humour too if possible - since some find it difficult to get their head around.
 
Thanks, don't all shout at once!!Wink



Replies:
Posted By: medicdog
Date Posted: 26 May 2008 at 7:56pm
Best of british mate, I dont know how you can make it humerous though. I found this some years back and set it to music, it at least had some effect on retentionWink
 

Based on ďKeep Yourself AliveĒ written by Brian May

 

I was told a million times on my first Respiratory day

That people with emphysema often breathe a different way
Receptors that react to PCO2 is the normal style
But if a person has had a high CO2 for a while
Body chemistry will cause those old receptors to decay
And so then the breathing triggers start to work another way

So that an extra high P02 is reason for alarm
Because a P02 that is high can cause a patient harm 

The hypoxic drive
The hypoxic drive
Knowing how it works will help keep your patients alive

Well Iíve told a million nurses in a million different ways
That itís P02 not FI02 that can cause malaise
So itís perfectly OK to give 02 at a high flow
Just as long as 02 sats stay ninety-two or three plateau
And Iíve said a million times that if a patientís turning gray
That you shouldnít hesitate turning up 02 all the way
Because if you continue monitoring in the proper style
Then youíll never have a problem never have a problem 

The hypoxic drive
The hypoxic drive
You must know it if you want your patients to survive 

The hypoxic drive
The hypoxic drive
Always keep the saturation below ninety-five
Hopefully this musical essay
Will keep you from sending somebody to their grave 

The hypoxic drive
The hypoxic drive
Knowing how it works will help keep your patients alive 

The hypoxic drive
The hypoxic drive
Many people use it to survive 

The hypoxic drive
The hypoxic drive
Knowing how it works will help keep your patients alive 

The hypoxic drive
The hypoxic drive
Many people use it to survive 

Always keep the saturation below ninety-five
The hypoxic drive
The hypoxic drive

 


Posted By: Firestreak
Date Posted: 26 May 2008 at 8:32pm
Well it made me laugh, thanks.  Queen just happen to be a favourite of mine.............. why didn't I think of that?!


Posted By: camster
Date Posted: 27 May 2008 at 10:16am
Can we put that in the reference section or somewhere where it won't disappear in a months time?

Epic!Clap


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Ruigidh an ro-ghiullachd air an ro-ghalar.


Posted By: Wamchop
Date Posted: 27 May 2008 at 1:59pm
I think we need to hear the fully audio version, complete with backing track!ClapClapClap


Posted By: camster
Date Posted: 27 May 2008 at 2:16pm
You offering to sing?





I found a load of lyrics http://www.rtlyrics.com/tableofcontents.htm#InServices - http://www.rtlyrics.com/tableofcontents.htm#InServices


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Ruigidh an ro-ghiullachd air an ro-ghalar.


Posted By: Wamchop
Date Posted: 27 May 2008 at 4:00pm
Originally posted by camster

You offering to sing?
 
we're supposed to be encouraging people not driving them to suicide!


Posted By: camster
Date Posted: 27 May 2008 at 7:13pm
Great! Here comes a lawsuit...........!

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Ruigidh an ro-ghiullachd air an ro-ghalar.


Posted By: mountainman
Date Posted: 27 May 2008 at 8:27pm
For those who dont like songs.

The stimulation for most people to take a breth results from high CO2.  In people with chronic chest disease such as bronchitus and emphasema the levels of CO2 build up so much the receptor become damaged and dont work.

When this primary mechanism fails the body has an alternitve mechanism to breath low oxygen.  Ie when oxygen drops we take a breth.  Because of this the stimulus to breath is low oxygen ie hypoxia.

The danger in a clinical context is that by administering high concentrations of suplemntary oxygen to thease patients there oxygen levlels don't drop suffeciantly to stimulate them to breath.

However to put this risk in context, only about 10% of COPD patients relay on this mechanism alone to breath.

It also needs to be born in mind that in the short term it is hypoxia that kills so in cases of acute medical emergencies and seriouse trauma high concentration oxygen should never be witheld.

When dealing with the exacerbation of the COPD patient we aim to titrate oxygen to about 93%.

Now to your scenario the vast majority of patients CFR will be seen for other reasons or if it is a copd patient presenting with a copd problem they are ofter in extreams and profoundly hypoxic and in the time it takes for and ambulance to arive a high concentration of oxygen is unlikly to harn.

Obviously if the patients respr rate is droping and LOC falling then oxygn should be removed however this is unlivly to happen in the short time a CFR will be with a patient.

Bottem line never with hold oxygen from poorly patients.


Posted By: camster
Date Posted: 27 May 2008 at 8:46pm
Sorry but it reads better in stanzas

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Ruigidh an ro-ghiullachd air an ro-ghalar.


Posted By: Wamchop
Date Posted: 27 May 2008 at 9:05pm

edit: obnoxious rant whilst irritated. Read it again. not helping. deleted it



Posted By: sitrep
Date Posted: 28 May 2008 at 7:52am
 Thanks mountainman for the exelent explanation


Posted By: camster
Date Posted: 28 May 2008 at 12:02pm
Sorry, I'm just musical

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Ruigidh an ro-ghiullachd air an ro-ghalar.


Posted By: Firestreak
Date Posted: 28 May 2008 at 1:57pm
Thanks MountainMan, that's exactly what I wanted and given my voice the better option as opposed to singing to my students!!


Posted By: chris.rigby.69
Date Posted: 23 Jun 2008 at 1:24pm
OK, I know that this thread is a few months old now, but I thought it better to post here than to start a new thread:
 
The more I think about hypoxic drive theory, the more I convince myself that it is illogical.
 
As an example: Charles Oliver Paul Dixon (See what I did!)
 
Charles has COPD. His normal average SpO2 is 90%. He is stimulated to breathe when it drops to 89% (I don't know how realistic these figures are, but for the sake of the question, it doesn't matter). Some incompetent patient transport bod turns up to take Charles to a hospital appointment, and shoves him on 100% O2.
 
Charles' SpO2 now rises when he breathes. Whereas before, his saturation would rise to say 91/92% on a breath, before lowering to 89%, at which point he is stimulated to breathe again, it is now rising to 95% at each breath. It therefore takes longer for the sats to drop to 89% although they still will eventually drop to this point, and therefore Charles' RR lowers.
 
QUESTION 1: Does this matter? Afterall, the same amount of O2 is getting around the body, just Charles needs to take less breaths to achieve this.
 
Charles has had the trauma mask on for ages now, and each of his breaths is now building his sats up to 99% (seems unrealistic, but bear in mind I'm just using these figures to make a point). It now takes a loooonnnnngg time for Charles' SpO2 to drop to 89%, and his RR is very low, say 2/min
 
QUESTION 2: Does this matter? Afterall, the same amount of O2 is getting around the body, just Charles needs to take less breaths to achieve this. (Yes, I know this is the same as Q1!) As I said before, if he's got a low RR, the sats will drop off between breaths, that is to say eventually he will get to the point that he is at his stimulation sats again.
 
Charles' sats hit 100%, and he's breathing at a rate less than 1/min. The ambulance has now arrived at the recieving hospital, where the recieving nurse removes the non-rebreather. At this moment in time, Charles' sats are 100%. Because he's no longer on supplemental O2, his sats now start to lower. About a minute later, his sats drop to 89%. This stimulates him to breathe, giving him a saturation of about 91% again. The hypoxic drive problem is therefore solved.
 
People don't die because they stop breathing. People die because their heart and brain stop functioning due to lack of O2. Slowing his RR by applying 100% O2 will surely therefore not kill him, as there is a high O2 saturation in his bloodstream. He will not stop breathing altogether, as eventually every time, his sats will drop again.
 
QUESTION 3: What is wrong with that arguement?
 
QUESTION 4: If the answer to Q3 is "nothing" why are people so worried about COPD?
 
edit: My god that's a long post! Also, I reckon maybe I should strictly have talked about SaO2, rather than SpO2


Posted By: medicdog
Date Posted: 23 Jun 2008 at 4:54pm
I can see your points, but I think its a little strong to call the PTS bods "incompetent" it is known throughout trusts that this is normal procedure to apply 02 for someone in breathing distress, there are many many discussions in regard to COPD, I in fact did a study on it over two years and never got a difinitive answer. If 02 is given then sats should be monitired, but it has been proven that in the average time it takes to get the patient to specialised care, ether ECP or hospital, any detrimental effects can be reversed generaly. You could ask this question a million times and you will get a million different opinions on COPD management.


Posted By: chris.rigby.69
Date Posted: 23 Jun 2008 at 7:46pm

I wasn't suggesting PTS bods are incompetent, just this one in the example, who hadn't considered the current standard practice of not routinely giving 100% O2 to COPDers.

It is my point exactly that in an ambulance scenario, it shouldn't make a difference.
 
I looked it up on Google Scholar, and found an article which suggested that the hypoxic drive problem is minor. The real problem, it claims, is the fact that haemoglobin carries both O2 and CO2, but the more O2 it carries, the less CO2 it can remove. This can then cause an increase in the acidity of the blood.
 
PS I've just qualified as a PTA with St John, so I'm not exactly going to claim that PTS bods are incompetent!


Posted By: resq
Date Posted: 23 Jun 2008 at 8:06pm
Chris

You are confusing oxygenation with ventilation, both essential for life.
 
People do die because they stop breathing. It is possible to oxygenate a patient using jet ventilation. which supplies high frequency high flow oxygen to the patient, however CO2 clearance is compromised.
When you  reduce your breathing you reduce your minute volume which means you  stop excreting CO2 this leads to a build up in CO2 resulting in  narcosis which leads to unconciousness, a blocked airway and death.
 
The return to conciousness after return of respiration takes time during which period the patient dies from a blocked airway
 
The key is not to apply oxygen then stare at a pulse ox screen. Observe the patient if their resp rate drops and level of conciousness drops reduce the inspired oxygen if you have reason to suspect type II resp failure


People should not worry about COPD.  it is a much overused term to describe a huge number of respiratory issues. The real proportion of the population who have Type 2 failure is quite small.

In conclusion any patient who is suffering from resp distress should have 15l/min via Non rebreath mask(Trauma mask) applied and that patient should be observed closely on route to an appropriate facility.

The real problem here is type II resp failure



Posted By: medicdog
Date Posted: 23 Jun 2008 at 8:07pm
So...are you saying then....if you as a SJA PTA turned up at a pt and they told you they had COPD, that you would not give High Flow (no longer known as 100% because you CANNOT deliver 100%)Oxygen? Do you have the skills and Knowlege to know what type and the conditions associated with COPD? "you looked it up on google" well have a look at my previous post and you will see that I have already stated that if you look at another 50 sites, you will probably get another 50 different opinions. There are NO recorded incidents of a pre-hospital pt with COPD/COAD dying because of a crew giving High Flow Oxygen....there ARE incidents of pt dying because they DID`NT  This isnt a critisism, its a very huge pond of confusing information within the medical profession, a great deal more pre-hospital and in hospital research is being carried out in this area. The general rule is; give high flow and monitor sats, resps, etc. scoop em off to the expertsWink


Posted By: medicdog
Date Posted: 23 Jun 2008 at 8:14pm
resq...you got to the button just before meBig%20smile


Posted By: chris.rigby.69
Date Posted: 23 Jun 2008 at 10:31pm

Resq and Medicdog,

Thank you, much of what you are saying is useful, and I shall take it on board. You have, however, to an extent misunderstood me, probably down to me not communicating my meaning well.
 
STANDARD protocol (as I understand it) for transport of a stable COPDer is to give O2 via Venturi/Combi mask, not via Trauma mask. this is where I think I confused the issue - I used the phrase incompetent to describe the attendant who mistakenly didn't follow the protocol, I shouldn't have done.
 
In my second post, I mentioned a BMJ article which suggests that 'Hypoxic Drive' is virtually insignificant, and I point out the effects of over oxygenation that it mentions. Perhaps I should have seperated this from the rest of my comments better.
 
I have no problem whatsoever giving a COPDer O2 via trauma mask, when it is necessary. That was the point i was trying to make with my original question - is it really going to kill them I asked. I was trying to put across that in an ambulance setting, it won't.
 
I guess I should have finished my second post with a comment about how the paragraph
Originally posted by chris.rigby.69

the hypoxic drive problem is minor. The real problem, it claims, is the fact that haemoglobin carries both O2 and CO2, but the more O2 it carries, the less CO2 it can remove. This can then cause an increase in the acidity of the blood
applies in the hospital setting.
 
The point I did a bad job of explaining is that I don't understand why people are so scared of giving high flow - hence actually agreeing with you both!


Posted By: medicdog
Date Posted: 23 Jun 2008 at 10:40pm
No problem my freind, the whole point of dicussion is learning something out of it. I know in the past I have written things down on the web as I see it, but its not like talking face to face where you can voice it and understand it better. Its just the way of these forums, what you see is not always what it seems, it tends to get sorted in the endWink


Posted By: chris.rigby.69
Date Posted: 23 Jun 2008 at 11:50pm
It was funny - Just Friday night, I was having a similar discussion with a friend, again about COPD, and again we got into a situation where we were arguing, only to later discover we both agreed with one another!
 
Must stop talking about COPD!
 
It amuses me that so many people either refuse point blank to give them (almost for the pedant :p) 100%, or only ever think trauma mask when they think O2.


Posted By: Mad Medic
Date Posted: 24 Jun 2008 at 10:16am
O2 however it is administered is one of the many, many tools we have available to us to treat a patient. Like any tool you need to be fully and properly trained in its use and when you have been trained you then make a judgement as to whether the tool is appropriate in this particular setting.
 
So over simplification but if I come upon a person who is in ACUTE respiratory distress they are going to get high flow oxygen, because I believe it is appropriate in this situation. As I am questioning them through the high flow mask and I discover their CHRONIC condition; because of my level of training it will increase my index of suspicion and therefore regularity of monitoring of this patient. That doesn't mean I'm going to sit there and stare at the Pulse Oximeter, which is another very useful tool, it means I'm going to be routinely checking and monitoring all the information available to me with regard to the patients condition, colour, skin temp, respirations (rate, rhythm & depth), pulse rate, oxygen saturation etc. etc. and then make a decision with regard to the patients treatment based on all this information.
 
Would I always give a sufferer of a CHRONIC illness high flow oxygen IF they were suffering from ACUTE  condition / illness damn right I would. Would I leave it on and merrily bimble off to hospital; not if I expect to keep being allowed to treat patients no. Treat the patient to the best of your ability and MONITOR THEM!


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Most of life's little problems can be solved . . . . . . with the judicious application of explosives!


Posted By: JonAcc
Date Posted: 24 Jun 2008 at 11:55pm
As with EVERYthing - treat the patient, not the condition



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