Rik Krohn was constantly exhausted. Even driving to work, he'd get so sleepy, he had to pull off the road and nap for 10 minutes before continuing on.
A sleep study revealed that Krohn had severe obstructive sleep apnea, a condition that caused him to wake up repeatedly all night long just to breathe.
In obstructive sleep apnea, the tongue and other soft tissue in the mouth and throat relax and collapse during sleep, blocking the airway. The episodes can last from seconds to a minute or longer. The brain senses the problem and awakens the sleeper to open the airway and start breathing again. The sleeper generally isn't conscious of all this activity, but their poor sleep quality tells the tale in the morning. And their partners suffer with the loud snoring that accompanies sleep apnea.
Krohn found out that he was waking up an average of 35 times an hour, gasping for breath, putting him at increased risk for heart attack and stroke.
"That got my attention," said Krohn, 68, speaking from his home in Burnsville, Minn. "I had a heart attack 20 years ago, and I didn't want to cause further damage."
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Different strategies have been developed over the years to alleviate the problem, with mixed results. Surgeons have tried removing tonsils and other soft tissue in the mouth and throat and installing implants to support soft tissue so it doesn't collapse during sleep. Dentists offer removable devices that move the tongue or jaw forward during sleep to prevent airway obstruction. The low-tech solution for overweight patients is weight loss, though that doesn't always work.
But the gold standard for sleep apnea treatment is a bedside machine known commonly as CPAP, for continuous positive airway pressure. It provides air during sleep with just the right amount of pressure to keep the upper airways open.
It works, but many people find the head strap, face mask and long air hose awkward. Some can't adjust to sleeping with the mask because it makes them feel claustrophobic. Others don't like having to take the machine along when they travel. And a few, like Krohn, have trouble with the mask's fit, which must provide a good seal around the nose. After trying several, he had to give up CPAP and figured he'd also have to give up his job as a software designer and find a way to live with the problem.
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Then he read about a clinical trial at a local hospital for a new implanted device that might relieve apnea. He was accepted into the study three years ago, got the implant and couldn't be happier.
"I got my life back," said Krohn. "It's made a big difference."
The Inspire Upper Airway Stimulation implant, made by Inspire Medical Systems of Maple Grove, Minn., is now in national clinical trials at 12 U.S. medical centers, including Tampa General Hospital, the only test site in Florida.
The Inspire implant uses technology that is similar to a cardiac pacemaker. A small pulse generator is implanted in the upper right chest, just below the skin; a wire lead with a special sensor on the end is placed between the ribs, and plugs into the tiny generator. A second wire is threaded up to the neck, below the jaw, and has a tiny cuff on the end that wraps around a nerve in the neck that controls tongue movement. The sensor in the ribs detects when the patient takes a breath and signals the generator to stimulate the nerve at the base of the tongue to move the tongue forward, opening the airway. The sleeping patient feels nothing. A handheld wireless programmer turns the implant on at night and off in the morning.
"The system is designed to be permanent," said Dr. Tapan Padhya, an ear, nose and throat specialist who heads the TGH study and is co-director of the USF ENT Sleep and Snoring Clinic. "But the battery and the housing of the stimulator will have to be changed in 15 to 20 years, just like you would with a heart pacemaker."
Tampa General will enroll 15 to 20 patients in the STAR Trial over the next year. Some requirements: moderate to severe obstructive sleep apnea caused by base-of-tongue obstruction, failed CPAP, willingness to have implant surgery under general anesthesia, and participation in followup tests and sleep studies for a year or more.
For Krohn, all that was worth it to get a good night's sleep, reduce his risk of a second heart attack and keep his job. And, to his wife's delight, he no longer snores. If he forgets to turn the implant on at night, a "home alarm'' goes off.
"It's called my wife. She gives me a jab in the ribs."
Irene Maher can be reached at firstname.lastname@example.org.