A “shallow water blackout” is a silent killer

In Jacksonville, Florida, a 50-year-old woman was found at the bottom of her backyard swimming pool. She was an experienced scuba diver who “often stayed at the bottom of the 9-foot deep end without oxygen to increase [her] lung capacity for future dives.”

Despite receiving CPR from her son, she could not be revived.

The Associated Press story about this tragic incident did not explain why a swimmer with her background drowned.

It appears to be a classic case of “shallow water blackout.” This phenomenon occurs when people hyperventilate before diving.

An increasing level of carbon dioxide (CO2) is what triggers the urge to breathe. Hyperventilating causes hypocapnia, a reduced amount of CO2 in the blood. If a swimmer uses up enough oxygen to pass out before the CO2 trigger point for breathing is reached, drowning will occur without notice. Victims are usually found at the bottom of the pool.

Here’s what it looks like in a diagram from Wikipedia:

A physician who lost her son to this little-known phenomenon started a websiteto heighten awareness of the problem. The site contains more information and stories about other drownings caused by shallow water blackouts.

Here is a video of a woman swimming laps of a pool underwater. Advance to the 0:50 point and watch what happens as she begins to slow down. [Addendum 8/13/15 12:50 pm: Warning. The video is graphic. It shows the unconscious swimmer being pulled from the water.]
 

A shallow water blackout may have been responsible for the death of Natalia Molchanova, the world’s foremost freediver, who went missing a few days ago.

Hyperventilating prior to diving is not recommended. Tell your friends.

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Chance can turn a surgeon into a killer

Risk-adjusted 30- to 90-day outcome data for selected types of operations done by specific surgeons and hospitals are now being publicly posted online by Englands National Health Service.

According to the site, "Any hospital or consultant [attending surgeon in the UK] identified as an outlier will be investigated and action taken to improve data quality and/or patient care."

After cardiac surgery outcomes data were made public in New York, some interesting unexpected consequences were noted.

Surgeons and hospitals resorted to "gaming the system" by declining to operate on patients who were high-risk and tinkering with patient charts to make those they did operate on seem sicker. This can be done by scouring the charts for all co-morbidities and making sure none are overlooked when they are coded. An article from New York Magazine explains it in more detail.

Interpreting outcomes data can be tricky.

In a post three years ago about a report that nine Maryland hospitals had higher-than-average complication rates, I pointed out that whenever you have averages, some hospitals are going to be worse than average unless all hospitals perform exactly the same way or, like medical students, are all above average.

A much more sophisticated way of looking at this subject appeared in a fascinating 2010 BBC News piece by Michael Blastland, who is the Nate Silver of England [or maybe Nate Silver is the Michael Blastland of the US], called "Can chance make you a killer?"

Blastland set up a statistical chance calculator for a hypothetical set of 100 hospitals or 100 surgeons performing 100 operations each. The model assumes that every patient has the same chance of dying and that every surgeon is equally competent. The standard is that a mortality rate 60% worse than the norm set by the government for any hospital or surgeon is not acceptable.

You are assigned one hospital. Using a slider, you may choose an operative mortality rate anywhere from 1% to 15%. After you do this a number of times and recalculate for each mortality rate, you will notice that the number of unacceptably performing hospitals or surgeons changes randomly for each percent mortality and your hospital may appear in the underperforming group strictly by chance alone.

The whole concept is explained in more detail on the site. I encourage you to try it for yourself. The link is here.

So it may be difficult for the NHS to separate the true outliers from the unlucky surgeons who happened to fall outside the established norms.

What do you think about this?

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Another Caribbean med school graduate needs advice

I did not attend St. Georges, Ross, or Saba. I chose my school because it has a premed program which leads to an MD program. My USMLE Scores on Step 1 and Step 2 CK are above 230.

I did not apply for the 2015 match because I did not have my step 2 CK results until November. It would have been too late. I could have rushed my step 2 but I wanted to get a good score and be a solid applicant. Also I would not have been able to complete my surgical electives in time to get letters of recommendation. At some point, I will be doing research at [a very well-known medical school]. I felt that for these reasons this would make me a better applicant the next year.

Since graduating I have been trying to find a medical related job (scribe) but have had no success. I have reached out to many institutions regarding research opportunities but have come up dry. I may be able to secure a volunteer research position by next month. Do you have any suggestions for me? I knew I would hate being out of the medical field for this long but this was my best bet. Does this gap hurt my chances?

I am concerned that despite your excellent USMLE scores, taking a year off from clinical medicine may cause your application to be rejected immediately. I do not know if a 9 week research elective, even at a premier med school, would be enough to offset your lack of clinical experience over the entire year. Acting as a scribe would not be considered clinical experience.

Another issue is what is the record of your school regarding matching graduates into surgical programs? Since you didn’t tell me your school’s name, I cannot give you any insight into that situation. Even if I did know the school’s name, it may not have published its match results.

To answer your specific questions:

How many gen surg programs should I apply to? I was thinking ~100. That seems reasonable. You should be able to gauge your chances better after you see if you receive any offers for interviews from the 100 programs.

During a gen surg interview, should I be open about my backup specialty? I would advise you to say that you would take a preliminary spot in general surgery if you didn’t match in a categorical position. Admitting that you would do internal medicine is often seen as a lack of commitment to surgery.

Most hospitals I am looking to apply are IMG friendly. Which means the surgery and medicine programs are both IMG friendly. Would it be a bad idea to apply to different specialties at the same hospital? I think it would be a bad idea. I suggest you wait and see if you get interviews from the general surgery programs. If you don’t, then there would be no problem applying to internal medicine at the same place. I doubt very much that the two services would talk about any specific applicants. Most surgery programs get hundreds of applications and those applicants who are not offered interviews are not remembered.

Some readers may have other opinions. I hope they will comment.

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Reaction to post on academia and social media

"Should social media accomplishments be recognized by academia?" a post of mine from October 4th, generated some lively discussion on Twitter.

Here are a few of the more interesting responses:

@ashishkjha Important question from @Skepticscalpel Should academia value impact on social media? Yes. And its coming. Slowly.

@MartinSGaynor Science comes 1st, 2nd, 3rd.. MT @ashishkjha Important Q: @Skepticscalpel Shld academia value impact on social media?

@ashishkjha agree how to measure impact a key question. Eye balls cant be enough. But too important a question to ignore.

?@DoctorTennyson Yes-I think social media has a role for #publichealth, #education, and fosters collaboration. More than obscure journals

@NirajGusani still you add value to your dept -how do/should they measure it?

?@gorskon Heck, at @ScienceBasedMed, we get 1M page views a month, but I get no credit.

@gorskon I agree though. For the most part, social media harms, not helps, academic career.

@gorskon Cranks complaining to my chair & cancer center director dont help.

@gorskon If I ever want to change jobs, Google searches will likely harm, not help, prospects

@Nadia_EMPharmD We actually asked this very question in a study we published this past year:

?@JBMatthews Academic tracks have been modernized in many places including ours; beyond # of publcns.

@JBMatthews As a journal editor and department chair, I believe its starting to "count"

?@nataliestavas We should study what has more meaningful impact, # of twitter followers or an article in the @NEJM

Most agreed that social media activity should count for something, but quantifying that something may be difficult. A certain number of followers or page views would not necessarily signify value.

Via email, Dr. Jeffrey B. Matthews, Dallas B. Phemister Professor and Chairman of the Department of Surgery at the University of Chicago, said his school of medicine created a new track for faculty that does not require traditional scholarship for academic promotion. It is non-tenure (tenure still requires traditional discovery and traditional measures of impact and importance), but there is otherwise no distinction of title.

To advance to professor requires evidence that the faculty member is outstanding. The chair and faculty committee must define what "outstanding" means, whether it is distinction in clinical practice like a high-volume, high-complexity specialty or a national draw of patients, in educational leadership such as a program director with leadership roles at APDS, ABS, RRC, or "other."

He added, "I would have ZERO trouble convincing our promotions committee that a high visibility blog with high traffic views that had evidence of thought leadership in the public domain would qualify as high impact and outstanding. And that is at the University of Chicago."

What do you think of the University of Chicagos progressive stance?

Have any other schools taken such steps?

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