Welcome to the Cave Diver's Forum.
  • Patent Foramen Ovale

    By Brad Starks 2002-11-26

    Normal Circulation

    PFO

    As you can see from the above illustrations, blood normally travels from the body into the right atrium (Venous circulation), then into the right ventricle and to the lungs. From the lungs blood travels to the left atrium and into left ventricle and lastly to the rest of the body. In a normal individual, If a bubble were to form in the venous circulation (i.e. air embolism) it would travel back to the right atrium and into the right ventricle and to the lungs. If the bubble is too large to pass through the pulmonary capillary bed then it would become lodged there and cause a pulmonary air embolism. If it was small enough to pass through the pulmonary capillary bed it would next travel to the left atrium, into the left ventricle, and into the systemic circulation. If the atmospheric pressure continued to decrease the bubble would enlarge and become lodged somewhere en route. It may be in the systemic circulation or it may be in the venous circulation. Where the bubble will lodge is purely dependent on its size and the size of the vessel it is passing through.

    In the case of a PFO, the process is similar. In this case, however, if the bubble formed in the venous circulation and was small enough to continue to the right atrium, it MAY pass into the left atrium and bypass the lungs thereby entering the systemic circulation. If the atmospheric pressure continued to decrease, while the bubble was in the systemic circulation, then the bubble would enlarge and become lodged. If it continued to be small, it would then travel back to the right atrium where again it MAY pass into the left atrium or it may go to the lungs. The point is....in either a normal individual or an individual with a PFO, the bubble will lodge somewhere and cause blood flow to cease thus causing hypoxia.....then anoxia...and finally cell death.

    The possibility of a bubble traveling from the right atrium into the left atrium ( in the case of PFO) is increased only when there is an increase in the right atrial pressure ( as in the case of pulmonary artery atresia, stenosis, or an obstructive lung disease. Normally, even with a PFO, the right atrium has an equal or lower pressure then the left atrium so if anything blood will be forced into the right atrium from the left.

    As you can see, PFO's do not increase the risk of an air embolism. It may have an effect on where the bubble lodges, but the result is the same. I hope this clears up any confusion. If anyone disagrees with my synopsis, please feel free to refer me to a research article that states the contrary. I am always interested in learning new ideas. Thank you!

    Brad Starks MSII
  • Recent Forum Posts

    twaldo

    Moving to FL, Tampa or Orlando?

    That was another thing I learned... DO NOT RENT OR BUY in Alachua county..... the short commute from ANY direction will pay for itself in property taxes and utility bills.

    twaldo 07-23-2018 12:53 AM Go to last post
    twaldo

    Moving to FL, Tampa or Orlando?

    After living in several places in Florida.... when I come back (unless there is a reason, like a job elsewhere) I will be looking at the Jacksonville area.... both for the plentiful IT jobs and the...

    twaldo 07-23-2018 12:51 AM Go to last post
    twaldo

    Burst disc's

    Just wanted to throw a THANK YOU out there... this has been a very informational thread.... both on burst disc's and O2 pumping.... has made me reconsider my AL 40 for O2 and now thinking an LP 50...

    twaldo 07-23-2018 12:47 AM Go to last post
    guruboy

    Santi Thermovalve - Apeks vs Si-Tech

    Does anyone happen to know how to tell an Apeks from an Si-Tech thermovalve? I?m assuming the diameter of the threads is different but can?t find any numbers.

    All the stores offer two options but...

    guruboy 07-23-2018 12:41 AM Go to last post
    Adler

    Moving to FL, Tampa or Orlando?

    I'm another one who travels a lot and chose to live in High Springs. I fly out of gville sometimes, but also opt for JAX, MCO and even TPA sometimes. It just depends on where I am going and timing....

    Adler 07-22-2018 11:38 PM Go to last post
    TraceMalin

    MrBil

    Very sad news.

    TraceMalin 07-22-2018 11:03 PM Go to last post
    pink arrows

    Tanks need a ride please!

    I also have a few tanks needing a ride... also from Marianna, also to High Springs... maybe our tanks can be road trip buddies :-) Anyone cool making a trip from the Mill Pond to Cave Country soon?

    pink arrows 07-22-2018 10:08 PM Go to last post
    rddvet

    Regulators

    Thanks for all of the good info. That's a prime example of why I don't service my own regs. Lots on tidbits and info you need to know from years of servicing them.

    I bought all of the mk10/g250s...

    rddvet 07-22-2018 10:03 PM Go to last post
    DA Aquamaster

    Burst disc's

    I'm in agreement with Tom that an accurate gauge is important. I have a calibrated (and re-calibratable) gauge that I plug in line when boosting O2, and as a check on the other two gauges in the...

    DA Aquamaster 07-22-2018 10:03 PM Go to last post
    DA Aquamaster

    Regulators

    I acquired my dozen or so Mk 10 G250s the same way for stage/bailout bottle use, but service them myself. The Mk 10 G250 is a great reg for use on stage bottles or deco bottles. It's a great...

    DA Aquamaster 07-22-2018 09:47 PM Go to last post
    whodunit68

    Moving to FL, Tampa or Orlando?

    I travel extensively for work and live in High Springs. I love-really enjoy- living here. I fly out of GNV when I can but my wife often goes on my biz trips. So, I'm one of those people who regularly...

    whodunit68 07-22-2018 09:38 PM Go to last post
    DA Aquamaster

    Regulators

    I have a couple Mk 15s in excellent condition that I'd sell with either D400 or X650 second stages. The D400s are in excellent condition and the X650s are near mint.

    The Mk 15 differs from the...

    DA Aquamaster 07-22-2018 09:33 PM Go to last post