Normal lung function requires the lungs to open and close to their maximum capacity, getting as much oxygen to the blood as possible. They are able to open all the way with the aid of a soapy material inside the lungs. "Now what happens if you take a little bit of water in there? That water washes away the soap on the inside so the lungs can no longer be open fully," he says. "Plus, the water's actually very irritating to the insides of the lung. So if the lung gets swollen, it shrinks and shrinks."
Dr. Oz says that Cassandra saw several signals but had no way of understanding their importance: that Johnny was suffering from reduced oxygen. First, he went to the bathroom on himself. "His oxygen was dropping, so he wasn't thinking right and went to the bathroom," Dr. Oz says. "That's a change of behavior."
Another key sign was that Johnny felt so tired. "Sometimes you get short of breath—not always. But you get really tired," Dr. Oz says. "And [Johnny] actually fell asleep, [Cassandra] thought, on the floor next to his bed. He never really got into the bed."
While Dr. Oz emphasizes that dry drowning is incredibly rare, he offers a few ways to protect your children. The best way is to teach them how to swim and not to swallow water, which can lead to mistaken aspiration—or letting water get sucked into the lungs instead of swallowed into the stomach.
Parents also need to be aware of three warning signs of dry drowning. "If your kid has shortness of breath coming out of the water, or they're not acting themselves, or they're really sleepy," Dr. Oz says. "You ought to at least get someone to take a look at them."