My Dominant Hemisphere

The Official Weblog of 'The Basilic Insula'

On the Pressures of Measuring Blood Pressure and All That Jazz

with 4 comments

Hi! Here’s a quick question. This exercise requires you to say the first thing that comes to your mind. Answer in a jiffy if you want to be honest with yourself! :

Q. What’s the value for normal blood pressure in an adult?

What? 120/80 mm Hg? Congratulations, you’re so wrong! Wait a minute, hold your horses!

Not as per the British Hypertension Society (BHS), it isn’t. The BHS defines normal BP as <130/<85 mm Hg. The JNC-7 report, on the other hand, calls <120/<80 mm Hg normal BP. (That value, by the way, is optimal according to the BHS.) In any case, 120/80 mm Hg per se, is not the right answer (though this value would be classified under normal by BHS guidelines). Note also that 120/80 mm Hg would NOT be classified under normal by the JNC-7 report.

In an era where precision and accuracy in medical affairs are paramount, this exercise underscores the importance of not being too quick in jumping to an answer without first looking up the pertinent guidelines, no matter how trivial the question. Evidence Based Medicine (EBM) is here to stay and as we find our memories inundated with cut-offs and criteria of all shapes, sizes, colors and forms, from the diagnosis and management of banalities like fever to that of more remarkable scourges such as asthma, rheumatoid arthritis, neoplasms and beyond, we must strive to keep that going if we are to look toward the future. This may not be very good for your mental health, but remember, it’s not you who we care about. The patient’s interest is always first!! 😛 As things start to get more and more complex and tougher to retain, it’s quite likely that we will have to take our dependence on computers a step higher in order to efficiently manage the information overload. Which brings us to medical informatics. But I won’t delve into that now. Perhaps in another post. 🙂

Your comments are always welcome. Sayonara for now! 🙂

——“Millions saw the apple fall, but Newton was the one who ASKED WHY.”
~ Bernard Mannes Baruch

Copyright © 2006 – 2008 Firas MR. All rights reserved.


Written by Firas MR

July 13, 2007 at 12:24 pm

4 Responses

Subscribe to comments with RSS.

  1. I hope you are not very busy, and since this article has been up for a while now and nobody has cared to comment, let me share a few words.

    I can’t stop reading this article – and reflecting that how naive us patients are. We believe anything the doctor says.

    I sent this article to my dad hoping to curm his tensions about measuring his blood pressure to the millimiter.

    He too has high blood pressure and just recently he was disgonised with aneurysm of abdominal Aorta.

    He replies that he’ll stick to what his doc says.


    August 4, 2007 at 3:11 pm

  2. Thanks for the comment Jaffer 🙂 . Dear buddy, ol’ pal 🙂 . Unfortunately, I’ve become crazy busy these days and that means lesser time for the blog. Hopefully, I shall try to maintain a slow but steady output of posts for readers.

    Undoubtedly true, patients aren’t aware of a lot of things when it comes to their treatment. What’s even worse is how many are led to believe that medical science as it’s practiced today is iron-clad stuff, when in fact it’s not. The truth is that a lot of what we do is based on educated guesses and we have only now begun to realize these uncertainties with the advent of ‘Evidence Based Medicine’ (EBM for short). There’s been an obvious shift in how precisely we measure these uncertainties over the last few years and what we do in their wake with regard to treating patients. Through EBM, we have now come to place emphasis on applied math (medical statistics) to make sense of gaps in our knowledge. No longer do we say, “you may live or die after this or that procedure” and leave it at that, but we can now put numerical values to these variables, with survival and mortality rates. That doesn’t do much for patients’ confidence however, but at least we are inching forward. If one tests positive for HIV on a given test, he or she would be comforted to know that there might be a say 20-30% chance of that being a false positive. As far as blood pressures go, there’s a statistical difference (in terms of morbidity and mortality) between OPTIMAL and NORMAL and that’s why the elaborate classifications and criteria.

    Healthcare systems that enforce ‘Good Medical Practice’ make sure to place priority on patient education. I hope your dad sails through his condition without complications. He’s right in ultimately choosing to follow his doctor’s directions. Because medicine still isn’t perfect, doctors are AS IMPORTANT AS THEY USED TO BE as decision makers. That’s their primary job. To make considered decisions with a CONSCIOUS lack of knowledge in this or that domain. Treatments need to be individualized in most instances and one size quite often doesn’t fit all.

    An excerpt from one of the medical texts about AAA (Abdominal Aortic Aneurysm; not the American Automobile Association 😛 ) :-

    “Until an asymptomatic AAA has reached a maximum of 5.5 cm in diameter, the risks of surgery generally outweigh the risks of rupture. All symptomatic AAAs should be considered for repair, not only to rid the patient of symptoms but also because pain often predates rupture. Distal embolisation is a strong indication for repair, regardless of size, because otherwise limb loss is common. Most patients with a ruptured AAA do not survive to reach hospital, but if they do and surgery is thought to be appropriate, there must be no delay in getting them to the operating theatre to clamp the aorta.
    Open AAA repair is the established treatment of choice in both the elective and the emergency setting, and entails replacing the aneurysmal segment with a prosthetic (usually Dacron) graft. The 30-day mortality for this procedure is approximately 5-8% for elective asymptomatic AAA, 10-20% for emergency symptomatic AAA, and 50% for ruptured AAA. However, patients who survive operation to leave hospital have a long-term survival which approaches that of the normal population. Some AAAs may be treated with a covered stent placed via a femoral arteriotomy under radiological guidance.”

    Source: Davidson’s Principles and Practice of Internal Medicine, 20e

    Some good patient ed resources:-

    The Merck Manual – Home edition

    Firas MR

    August 8, 2007 at 12:13 pm

  3. Thank you for the reply. Consider putting it up as a post !

    My dad is being operated on in Suleiman Fakeeh tomorrow afternoon.

    While reading your reply, I had a feeling that like patients of doctors, customers of engineers have the very same approach.

    When a lay customer approaches an engineer, he has that feeling that the engineer will always do the right thing for his project. He will do the right analysis, perform the right calculations and quote a reasonable price.

    And when something goes wrong, it all goes back to the Engineering department. (Thou shalt hearken Dilbert)

    Currently I am doing Engineering Physics at McMaster University and our faculty, with the help of Bio-Med engineers, is trying to develop a (pill) capsule, that would take pictures of the insides of the digestive tract.

    I hope to be working on it soon and am pretty excited about it.

    Of course that pill would be one time use only !


    August 8, 2007 at 5:42 pm

  4. You are welcome! Hope your dad’s surgery goes well and he recovers to his usual self, God-willing. Suleiman Fakeeh’s quite famous. Has tie-ups with numerous overseas hospitals, not to mention Harvard (USA). But I’ve heard of it being mind-bogglingly expensive. Hope your dad’s using insurance or something to cover those costs. Wish him luck from my side!

    As for the pill, I believe it does already exist. It’s called a ‘capsule endoscope‘. If you guys are going to be working on this technology, you’d need to work toward making its engineering better and most importantly, make it a lot less expensive for it to have any effect on the way things already are currently. Only technology that survives cost-benefit analyses has any hope of long term acceptability and wider use. Good luck with the project. 🙂

    Here’s another patient-ed resource; allows you to watch live surgeries that may be of interest to you, before you eventually end up under the knife yourself. It’s called OR-Live. Many AAA repair videos available on first glance. Do check it out. 🙂

    Firas MR

    August 8, 2007 at 6:01 pm

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: