Margaret Murphy didn't know what was wrong. She'd wake up several times during the night gasping for breath.
Tests showed that her heart was fine, but her sleep problems persisted.
"It was getting me scared to the point where I thought I was going to have a heart attack," said Mrs. Murphy, 54, of Westminster.
After spending a night in Carroll County General Hospital's new sleep and breathing disorders lab, Mrs. Murphy learned what was causing her fitful sleep.
Doctors determined that her air passages were narrowing while she slept, restricting the flow of oxygen to her heart.
The sleep lab outfitted Mrs. Murphy with a pressurized mask that keeps her breathing passages open to allow proper air flow.
"I'm just glad they were able to find out what was going on," Mrs. Murphy said.
Carroll County General will hold an open house today from 5 p.m. to 7 p.m. to introduce the sleep lab to the community. Specialists in sleep disturbances will be available to answer questions and describe procedures used to diagnose and treat sleep disorders.
Since it opened two months ago, the unit has treated two or three patients a week, said Dr. Natvarlal Rajpara, the sleep lab's medical director.
Dr. Rajpara, who also chairs the hospital's department of critical care medicine, came up with the idea of opening a sleep lab to avoid sending local patients to sleep centers at Baltimore hospitals.
The lab is a two-bed facility designed to diagnose and treat patients who are experiencing symptoms of sleep disturbance. These may include insomnia, excessive snoring, abnormal movement during sleep, unexplained weight gain and chronic daytime fatigue.
"The main complaint is, 'I stayed in bed for eight hours but didn't get a good night's rest,' " Dr. Rajpara said. "People wake up and they're tired as if they'd been up all night."
The lab is equipped to do all-night sleep studies on patients who are having difficulty getting a good night's sleep.
In preparation for the study, a sleep lab technician attaches 16 electrodes to the patient to monitor brain waves, heart and breathing rates, and the amount of oxygen in the blood.
At about 10 p.m. the patient goes to sleep in a small, quiet room, and the technician remains outside to monitor brain wave activity. The patient is videotaped to determine if there are unusual movements, night terrors or seizure activity. The study ends about 6 a.m.
Dr. Rajpara said the most common diagnosis is sleep apnea, a disorder in which the person's airways become blocked and cause periods of nonbreathing. These episodes can occur as frequently as several hundred times per night.
If not detected and treated, sleep apnea can be life-threatening. It can also cause hypertension, personality changes and irregular heart rhythms.
In Mrs. Murphy's case, the tissue in her throat had swelled, leaving her airways very narrow. Now she uses a "continuous positive airway pressure" mask, a device worn over the nose and attached to an air compressor, to keep the airways open.
Sometimes sleep apnea is caused when the brain doesn't give the signal to breathe, Dr. Rajpara said. This condition can be treated with medication.