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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That time Skeptical Scalpel wasn’t skeptical enough

Yesterday I retweeted a link to “Live Action News,” a website with a video claiming that Planned Parenthood was selling fetal organs.

I had watched the video and read the accompanying article but failed to engage my skeptical radar. It turns out that the video was maliciously edited to portray Dr. Deborah Nucatola, Senior Director of Medical Services for Planned Parenthood, in the worst possible way. The video showed her “having lunch with actors posing as buyers who are interested in purchasing the body parts of babies who have been aborted” and discussing prices.

The website Media Matters describes some of the edits and explains why they are deceptive. It turns out that of the 150 minutes of the original footage, only 8 minutes were used in the "Live Action News" clip.

If I had watched the video more closely, I wouldn’t have needed Media Matters or the 150 minutes of original footage to see the flaws.

First of all, it begins with an introduction by a former ABC News anchor Connie Chung promising something shocking. But as you can see in the screen shot below in the lower left corner, it clearly says “ABC News 20/20 March 8, 2000.”

Another obvious clue is that the date and time stamp in the lower left-hand corner of the edited video itself is “2014 07 25.” In retrospect, it does not seem plausible that an anti-abortion organization would have sat on this inflammatory story for almost a year before releasing it.

In addition, the times differ greatly as the video progresses which obviously should have told me that major editing had taken place.





The "Live Action News website looks pretty bogus too.


I am very disappointed in myself for having fallen for this dishonest garbage.

It won’t happen again.

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