rock_shoes Posted May 28, 2011 Share Posted May 28, 2011 (edited) Very close. Why would this "jet" of fluid be inclined to travel into the right over the left? What is so special about having the distal end of the ETT positioned so close to the tracheal wall as the case is suspected in this patient? Is there a physical principle of fluids that may describe this behaviour? Take care, chbare. It's all about the path of least resistance. If there is less resistance into the right lung then that lung will fill first. Considering that the patient in question has tracheal deviation angled towards the right it stands to reason that direction will have the least resistance. I suspect in this case rotation of the ETT reduced resistance to leftward flow sufficiently to balance out lung expansion. Not something I've ever seen in practice but theoretically possible. Edited May 28, 2011 by rock_shoes Link to comment Share on other sites More sharing options...
chbare Posted May 28, 2011 Author Share Posted May 28, 2011 Yes, until the flow of fluid reached the carina. Both paths would be roughly as easy, but something kept the flow of fluid on the right side. It's not intuitively obvious, but there is an effect that can be thought of as a special case of the Bernoulli effect. Take care, chbare. Link to comment Share on other sites More sharing options...
chbare Posted June 6, 2011 Author Share Posted June 6, 2011 Hello everybody, I just wanted to follow up on the scenario. I based this scenario off of the following case study: http://bja.oxfordjournals.org/content/100/6/859.full The Coandă effect is basically the tendency for a jet of fluid to want to attach to a surface near said jet. In this case, the physiological deviation positioned the ETT in such a manner that the jet of fluid from the distal end of the ETT attached to the right tracheal wall and followed the path into the distal parts of the right lung. Then, when the back pressure essentially overcame the effect, air "backfilled" into the left lung. This is what led to the asymmetrical chest motion. Pulling the ETT back made no difference, but rotating the tube repositioned the jet of fluid coming from the ETT, thus most likely resolving the issue. A basic demonstration of the Coandă effect: Take care, chbare. Link to comment Share on other sites More sharing options...
Kaisu Posted June 6, 2011 Share Posted June 6, 2011 Nice! People like you make this site worth visiting. Good stuff chbare. Thanks. 1 Link to comment Share on other sites More sharing options...
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