Nathan asked me so intersting question, that I decided to post it:” Dr. Yakubovskyy, I was wondering if you could elaborate on why the squatting position is common in pts with Tetrology of Fallot. The only explanation I have found is that it presumably lessens the right to left shunt. I've tried to dig deep into my physio knowledge to explain it but can't come up with an answer that is satisfying. Thanks”.
The answer: As you know, TOF is a relatively common and very serious congenital heart defect. The major problem in patients with TOF is severe cyanosis (hypoxemia) associated with right ventricular outflow tract obstruction (RVOTO) and reduction in pulmonary blood flow. Squatting is a mechanism that helps patients to cope with an acute attack of cyanosis. There are not very many recent publications, which shed light on the protective mechanisms of squatting in the patients with TOF; the last one appeared in 2002 with the major postulated mechanism as the reduction of amount of deoxygenated blood entering the systemic circulation through VSD. Besides that, there are few more possible protective mechanisms, which deserve to be mentioned here. To save space I combined all known (for me) effects of squatting in the patients with TOF and presented in the diagram below. Enjoy.
Dr. Y.
1 comment:
That's a great example of how spreading knowledge immortalizes one, or at least causes an effect that reaches far beyond... This post was made in 2009 and its value is still tangible now after almost a decade. Thank you sir for such great contribution to all knowledge seekers.
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