[indaemed] Re: Re NMS
- From: SS Mishra <ssmhialt@xxxxxxxx>
- To: indaemed@xxxxxxxxxxxxx
- Date: Mon, 15 Mar 2004 21:10:25 +0530
Well! I am quite privy to the whole case and its entire history. I think
Sanjeev had not placed all the facts before the list in his recent mail, as
presumably he took it for granted that everyone was aware of his earlier
e-mail and the history of the case. Apparently, there are many recent
members of the list, including Bish Sir, and they are not completely aware
of all the facts. As for as I am concerned, he had an episode of
unconsciousness without much provocation earlier, and all the tests were
normal. On a provocation, he had a repeat, and the tests were normal again
(may be barring tilt table - his first tilt table was normal). Now, a
negative tilt table does not rule out vasovagal susceptibility. It has an
alarming number of false negatives and false positives. In my opinion, the
pilot is rightly grounded, as his routine training provocation can lead to a
repeat of his unprovoked response earler. Better an element of doubt,
rather than an unfortunate repeat in air and an unnecessary loss of life and
aircraft. As for as hypoxia to 30,000 ft is concerned, it could have led to
LOC by itself, but why only in THAT person, and not in others?- shows poor
tolerance anyhow.
Just my Paisa worth
Sudhanshu
----- Original Message -----
From: "USM Bish" <bish@xxxxxxxxxxx>
To: <indaemed@xxxxxxxxxxxxx>
Sent: Monday, March 15, 2004 8:27 PM
Subject: [indaemed] Re: Re NMS
> On Mon, Mar 15, 2004 at 06:40:51PM +0500, anujc@xxxxxxxx wrote:
> >
> > I agree 110% that the diagnosis of VVS MUST NOT be done based
> > on LOC in a altitude chamber. Let me clarify that this was not
> > the case. If I remember correctly, the diagnosis of VVS was
> > made independent of the LOC episode. I may be corrected on this
> > since I was not privy to the initial work up of this cadet.
> >
>
> This puts a new dimension on the case. As of now, all that I
> was going by was the inputs of the OP. Could somebody aware of
> the full case enlighten us on issues not brought out earlier ?
>
> > My aim of posting the VVS and HUT part was since somebody
> > mentioned that HUT was not done for this subject during the
> > last review and suggested that it should have been done. Since
> > I was the one who turned down the HUT request in this case, I
> > thought I must share my POV. I may also add that in a large
> > percentage of cases labelled as VVS, none of the ANS studies
> > show any abnormality. If one goes thrrough available literature
> > on the subject, the etiopathology of VVS may vary from ANS
> > dysfunction to cerebral blood flow autoregulation problems to
> > peculiar neural activity in the brain. There are even reports
> > to suggest that VVS may be a manifestation of abnormal
> > electrical act ivity in the brain, on the lines of temporal
> > lobe epilepsy!
>
> You are dead right here. I think the suggestion for ANS study
> was more or less an attempt at completing the full battery of
> tests. A positive result would definitely give a clue, whereas
> a negative perhaps, does not mean anything at all. Repeat HUTs
> scarcely give altered responses ...
>
> > It would be worth remembering that if this cadet did have a VVS
> > as an independent occurence, he could be prone for other reflex
> > neural phenomenon as well. (this is documented in literature. I
> > think even Gillies mentions this somewhere.) In such a setting
> > his LOC under hypoxia is not surprising at all!
>
> This is the first time that I am reading on this thread that
> the cadet had a VVS as an independent episode ... I got the
> impression that it was hypoxia induced only.
>
> > The second factor that should be kept in mind is his high
> > degree of aerobic conditioning. He had a resting HR of about 50
> > beats per min. I have seen syncope cases in NDA cadets while at
> > AFMC where simply going easy on aerobic conditioning cuts down
> > the recurrence of syncope. The point however in this case is
> > that the cadet had a solitary episode of syncope and not
> > recurrent ones. Whether this was in any way subsequently
> > related to his LOC in the chamber can be argued.
>
> High aerobic conditioning need not mean a predisposition to
> VVS. Bjorn Borg had a basal HR of about 40, and Mike Tyson
> about 44 without VVS episodes. Kip Keino too had a similar
> basal HR. Whereas on the other hand, we lost a Medical Officer
> with probable VVS in a swimming pool 2 years ago ! He had a
> basal HR of about 48. Prediction of possibility of a VVS in a
> case of low basal HR is perhaps a rather grey area ...
>
> Bish
>
>
> --
> :
> --------------------------------------------------------------
> Wg Cdr (Retd) US Mohalanobish bish@xxxxxxxxxxx
> GF-01, Carleston Classic usmbish@xxxxxxxxxxxxxx
> 03, Carleston Road +91-80-30611448
> Cooke Town, Bangalore - 560005 98451-71863 (Mobile)
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> :
>
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