As a medical advisor to an ambulance service this issue is a constant thorn
in the side. Our respiratory physicians still argue that in a patient with a
hypoxic drive high flow oxygen leads to acidosis and unecessary additional
deterioration and occassionally writes to me about individual cases.
What do we do here at present:
1. As part of an "action plan" study most of the patients woth C0PD in our
small town have a treatment plan which advises th ambulance service on
initial oxygen flow
- no more than a handful of patients have been identified as being reliant
on hypoxic drive and an initial flow rate of 24% advised.
2. As a general rule our ambulance service are guided by 02 saturation
(pulse oximetry). They are advised to adjust oxygen flow in known/possible
COPD patient who is in acute distress to acheive a saturation of 90-94%
ONLY. Often this requires less oxygen than you think.
3. If the patient happens to be crashing LVF the chances of acheiving such a
saturation in the early stages even with high flow oxygen are slim and they
should be most unlikely to be turning the O2 down.
This approach seems to keep everyone reasonably happy
But in a small town most of the patients are well known
JohnC
-----Original Message-----
From: francis andrews [mailto:[log in to unmask]]
Sent: Wednesday, 29 March 2000 21:45
To: [log in to unmask]
Cc: acad-ae-med
Subject: Re: COPD and Oxygen
Mike
DEFINITELY high flow. You were in the right. Remember that
patients frequently die from hypoxia, but not from CO2
retention. In your case myocardium needs oxygen and COPD
patients frequently have co-existing myocardial disease. It
is easily possible to keep patients alive on high flow O2
but with a poor repiratory effort (and high CO2)-much more
difficult the other way round. On ICU, we frequently
ventilate COPD and asthma patients with a very low
frequency and tidal volume to avoid air trapping but with a
high FiO2- CO2 levels often become extremely high but the
patients remain oxygenated and survives. I frequently get
referrals from the wards and A&E to assess COPD patients to
see if they are suitable for ICU. About 50% get better
there and then because I turn up the oxygen to cure their
hypoxia and hence respiratory muscle hypoxia etc, induced
by 24%FiO2! In virtually all cases, there has been no
demonstration that the patient has a hypoxic drive. It is
true that a SMALL minority of COPD patients have a hypoxic
drive, but in my view it is safer to oxygenate them
properly first and keep an eye on their clinical condition
and adjust according to gases etc + there is always
non-invasive ventilation to help them. This has been
commented on fairly recently in the letters page of the BMJ
by a number of intensive care docs who are fed up at being
referred hypoxic patients from people who ought to know
better. Ask any intensivist if you don't believe me!
Cheers
Francis Andrews FFAEM
Lecturer in intensve care medicine/hon. Spr in ICU & A&E
University of Liverpool/Whiston hospital
[log in to unmask]
On Wed, 29 Mar 2000 01:14:03 +0100 Michael Bjarkoy
<[log in to unmask]> wrote:
> My protocol in the ambulance service states that I should give an FiO2 of
> 0.98 to acute COPD.
> I recently had a patient on my bus who had a high lateral infarct with CCF
-
> ONF very poor. NO evidence of COPD.
>
> At the receiving hospital I was asked to take the patient off high flow O2
> and reduce to 24% for COPD even though there was no PMH of this. This has
> bothered me ever since as there was no obvious indication of COPD at the
> time.
> The questions I must ask - as I must be assume ignorance are -
>
> How does COPD present as an acute and new onset as opposed to CCF with
AMI.
>
> All the paramedic manuals state COPD in an emergent situation should be
> given high flow O2. Is there a change of thinking here or are the
ambulance
> services ahead of AEU.
>
> I thought I was right and unless you chaps can produce evidence to the
> contrary I shall assume the evidence I have to hand is correct and the doc
> wrong.
>
> High flow or not - that is the question.
>
> Mike Bjarkoy
> Paramedic
> Sussex
>
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