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Editorials

Should oxygen be given in myocardial infarction?

BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.c3287 (Published 17 June 2010) Cite this as: BMJ 2010;340:c3287

Rapid Response:

History is only a catalogue of the forgotten.

Dear Editor,

Professor Dan Atar's editorial reminds me of the time when I was once
accused of not following the protocol of giving routine IV lignocaine to
every one admitted to the CCU at The Middlesex Hospital. I had
specifically asked the SHO not to administer liognocaine as both of us
thought, at that time, that the said patient did not have any acute MI. He
was discharged the following day when all tests proved negative.

Since the boss was away I had to take the responsibility as the SR.
That was the time I found out, to defend myself, way back in 1972, that
while there were only two studies out of the total of seventeen,
supporting the use of routine lignocaine to suppress arrhythmias,
remaining 15 studies did not support that belief. Despite that lignocaine
became the standard protocol! Both my consultants, Late Walter Somerville
and Richard Emanuel, stood by me. I survived.

When one goes deep into any practice on the bed side one could find
situations like giving oxygen routinely to every acute MI without solid
data to back it. Another was administering morphia in acute LVF. We could
expect to see in the near future the dangers of suppressing the autonomic
nervous system in acute MI like situations with beta-blockers and ACE
inhibitors. The autonomic nervous system initiates and completes the
natural remodelling of the left ventricle after an AMI. That could be
interfered with by suppressing the inbuilt repair mechanism mediated
through the autonomic nervous system. [1]

Professor Beasley was one of the persons who has gone deep into
oxygen therapy in AMI. His study of the limited number of controlled
trials did show that routine oxygen, in fact, harmed patients. [2]
Beasley’s historical perspective is exhaustive for anyone interested in
this area. [3] It was Steele who started this practice through his article
in the BMJ in 1900. [4] But even as far back as 1949, 1950, 1965 and 1976
there were enough studies showing that routine oxygen is harmful in AMI
[4, 5, 6, 7, 8] One study even showed that good risk AMI patients below
the age of 70 are much better off left at home than being rushed to CCUs
in those ambulances hurtling through dense traffic with their shrill
sirens. [9]

However, the common man gets upset if the patient does not get oxygen
as the media and, even the motion picture industry, depict routine oxygen
mask after a heart attack as a must! Cochrane group has asked for more
detailed RCTs on the subject, preferably placebo controlled. That might
take time and lots of money. I doubt if that would take knowledge any
further as the weight of existing evidence is against giving routine
oxygen in acute ischaemia. Excess oxygen is shown to reduce blood flow to
the heart, brain or kidney when they have an ischaemic episode unless
there is severe hypoxia.

Yours ever,

Bmhegde

References:

1) Poise and CADD studies.

2) Beasley et. al. Oxygen in acute AMI. Heart 2009; 95: 198-202.

3) Beasley et. al. Oxygen in AMI-history. J. R. Soc. Med 2007; 100: 06-
0065.

4) Steele C. Severe anginal pain relieved by oxygen. BMJ 1900; 2: 1568.

5) Boland EW. Oxygen and pain relief in acute coronary thrombosis. JAMA
1940; 114:1512.

6) Russek HI, Regan FD, Neagele CF. 100% oxygen in AMI and severe angina.
JAMA 1950; 144: 373.

7) Thomas M, Malmcrona R, Shillingford J. Haemodynamics of oxygen in acute
MI. Br. Heart J 1965; 27: 401.

8) Rawles JM, Kenmure ACF. Controlled trials of AMI. BMJ 1976;53: 411-417.

9) H G Mather, D C Morgan, N G Pearson, K L Read, D B Shaw, G R Steed, M G
Thorne, C J Lawrence, I S Riley. To compare the results of home and
hospital treatment in men aged less than 70 years. Br Med J 1976;1:925-929
(17 April), doi:10.1136/bmj.1.6015.925.

Competing interests:
None declared

Competing interests: No competing interests

18 June 2010
BM Hegde
Editor in Chief, J. Science of Healing Outcomes
Mangalore-575 004, India