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

    ddunlop

    Suex XJ-37 DPV

    Looking to sell my DPV, really fast and fun. Newer model, purchased from Suex dealer in south Florida back in May. Has some marks in the nose from normal cave use, but overall in good shape. ...

    ddunlop 10-17-2018 08:55 PM Go to last post
    Sly-vester

    Hurricane Michael

    Glad you're OK.

    Sly-vester 10-17-2018 08:55 PM Go to last post
    MORGAN

    Looking for a Nitek Duo back door

    Thanks!

    MORGAN 10-17-2018 08:15 PM Go to last post
    Squirrel Girl

    Echo River Spring KY

    I think Wes was diving in the area back then. Mark Wenner might know the history.

    Squirrel Girl 10-17-2018 05:24 PM Go to last post
    tflaris

    Steve Boyer needs our help

    I wanted to reach out again and kindly ask for your donations to help out Steve Boyer.

    Donate a little, donate a lot.
    ...

    tflaris 10-17-2018 05:14 PM Go to last post
    Draker

    Sidewinder Options

    I?ll take them.


    Sent from my iPhone using Tapatalk Pro

    Draker 10-17-2018 04:38 PM Go to last post
    jlillest

    Echo River Spring KY

    2017 may be referring to the submersible that was used in the spring. I don't know the full story, but I believe it didn't make it far, got tangled in the original exploration line and had to be...

    jlillest 10-17-2018 04:22 PM Go to last post
    jlillest

    Sidewinder Options

    Ok, cool. I understand now why you were calling them brackets. :)


    I was looking for the sewn soft-plate that I bought with my unit. Thanks for showing pics, but this is not something I'd be...

    jlillest 10-17-2018 04:18 PM Go to last post
    Doby45

    Is Cave Training BS?

    That cat is mad at the world though, look at it's face!

    Doby45 10-17-2018 03:53 PM Go to last post
    rddvet

    Sidewinder Options

    Here are those brackets they're using. I just want to get my money back on them, they were $60. Let me know if you're interested, if not somebody else is second in line.

    ...

    rddvet 10-17-2018 02:48 PM Go to last post
    FW

    Echo River Spring KY

    My first guess would be Ron Simmons. Next might be Sheck Exley. I *think* Shecks logbook is still around. maybe with Mark Long???

    FW 10-17-2018 02:10 PM Go to last post
    jeandiver

    Looking for a Nitek Duo back door

    Mike : I can bring a couple of old Nitek's I have to see if they will work. (There not duo's but maybe have the same cover)

    Jeano

    jeandiver 10-17-2018 01:37 PM Go to last post