Thursday, November 18, 2010
Electrical Stimulation Eases Asthma Attack
Here’s a shocking way to help asthma patients catch their breath during a sudden and severe attack: Deliver tiny electrical impulses under the skin in the neck.
Researchers from five U.S. institutions have found that electrical stimulation can safely be used to open the airways during an acute asthma attack when traditional medications do not work. According to the American Lung Association, about 23 million Americans are living with asthma.
The small study involved four conscious and responsive adults aged 26 to 58 who visited a hospital emergency room during a moderate-to-severe asthma attack and whose symptoms did not improve after using inhalers and powerful anti-inflammatory (steroid) medications. Such treatments were considered a failure if the patient scored 70% or less on a lung function test that measured how much air could be forced out of the lungs after taking a deep breath. This is called force expiratory volume, or FEV. The amount of air forced out in the first second is known as FEV1.
The electrical stimulation technique is a minimally invasive procedure that is done while the patient is awake. Anesthesia is applied to the neck, and then the doctor inserts an electrode under the skin into the tissue surrounding the carotid artery and vagus nerve. Live ultrasound images are used to help guide the placement.
The study participants received mild but continuous electrical pulses for three hours, ranging from 1-12 volts. The voltage was increased until symptoms improved or the stimulation triggered muscle twitching or discomfort.
Researchers compared breathing measurements taken before the stimulation to those obtained every 30 minutes during the procedure and after the stimulation was complete.
A half-hour into the treatment, the patients could blow more air out of their lungs after taking a deep breath. Their FEV1 scores remained increased for 30 minutes after treatment.
The study team says electrical stimulation may provide a drug-free and non-airflow-dependent method of opening the airways in critical asthma attack situations. They will announce their findings in San Diego this week at CHEST 2009, a meeting of the American College of Chest Physicians.