Swan Sandbox

(click to open in itunes)

I don't understand. What is this?

Back in the days of the mighty Respirosaur (The last dinosaur pulmonologist), we put Swan-Ganz catheters in everyone who came through the doors of the MICU. Then we realized we were killing people with our Swans (the catheters...not the birds). Ah-hem, oops. And so we put in fewer and fewer swans all the time. I agree with this approach. That being said, there are few situations now where have a Swan may be useful in settling a debate on whether pulmonary edema is cardiogenic or non-cardiogenic. A Swan is THE ONLY way to diagnose pulmonary hypertension. And I have seen a Swan diagnose and severe elevated wedge pressure in cardiomyopathy patients that are seemingly hiding their fluid in parts of the lungs that chest xrays can't reach.

As with all things, we swing from doing them too often to overcompensating and doing them too little. Part of the problem being that if you aren't doing them often they become more difficult to do successfully and more difficult to interpret. Swan waveforms are particularly difficult to interpret if you are not accustomed to them. I have been lucky to come from a Pulmonary Fellowship with a strong Pulmonary Hypertension program. I have probably done more Swans now than some Critical Care Physicians will do in their entire career.

This progam is a toy. It will not interpret a waveform that you feed into it. It will given you the basic waveforms as you move the catheter through the different parts of the cardiovascular system. Then you can change physiologic properties to see how the waveform is affected. This is a playtoy that you will need to experiment with to learn from. A side bar tells you exactly how the waveform is changing to your input. So you have written feedback as well on what is occuring.

Do you just take a lot of images of waveforms and play them like videoclips depending on what I select?

Absolutely not. I generate all the waveforms mathematically. And I apply your physiologically selections mathematically to the waveforms so that different conditions can be additive. Seriously, I had to go back and relearn trigonometry to write this app. Do you remember trigonometry? I didn't. And I never really enjoyed it until I had to apply it in this setting.

Do you really think this is useful for physicians?

If you are my PCP, please, god don't you ever try to put a Swan in me. But if you are a Cardiologist or a Critical Care physician, this is bread and butter. You have to know this stuff and I think this is the best program for learning it. Again, you have to spend time actually playing with the program and watching how different parameters change the waveforms to learn. Don't expect that just by putting this app on your phone and spending two minutes on it that you will somehow magically grasp what denies most common physicians.

How come there are no reviews of this app?

For one thing, because I never bother people with "please review my app" pop-ups. That may change if I continue to get zero reviews. So if you like this, rate it. If you don't like it...whatever, rate it as well. But if you don't like it, what helps me more is if you email me and let me know how I could change it to be better...alienanorexia@gmail.com

Can you include a calculator to analyze Swan numbers?

I started on that problem one weekend. But the algorithms are shaky at best. You really need some kind of understanding of the patient's clinical situation and the question that the Swan is trying to answer before you get any good analysis. I was unhappy with the algorithm results and so am not including it. I would rather not give you information than give you bad information.


The Mandatory Disclaimer: All information on this website is purely for educational and training purposes. Use best clinical judgement, the most current reference articles, medical standards of care, and specialist consultations when making clinical decisions for your patients.

Last Updated March 6, 2014