The Diaphragm Pacing System is an implantable diaphragmatic/phrenic nerve stimulator that provides support for patients with chronic ventilatory insufficiency whose diaphragm, lungs and phrenic nerves have residual function.

The application of repetitive stimulus patterns to the phrenic nerves causes smooth, rhythmic contractions of the diaphragm, which result in the inhalation of air into the lungs. The pacing system consists of electrodes sutured to the phrenic nerves, radio receivers implanted in subcutaneous pockets, and an external transmitter/antenna assembly that provides power to the system via 9-volt batteries.

The external transmitter and antenna send energy and stimulus information to the passive receives implant. The receiver translates radio waves into stimulating pulses that are delivered to the phrenic nerve by the electrode. The diaphragm muscle contracts and produces the inhalation phase of breathing. The transmitter then stops generating signals, which allows the diaphragm to relax, and exhalation occurs. This cycle of signals followed by no signals is repeated automatically by the transmitter, producing a normal breath­ing pattern.

The transmitter contains the controls used to individually adjust the parameters of stimulation to suit each patient. Over 1,000 phrenic nerve implants have been performed throughout the world since 1968. Patients from several months of age to over age 80 years have been successfully implanted and paced long term. Many patients

Have been successfully paced for more than10 years and the longest patient has been pacing continually for over 20 years. Recent technologic developments in diaphragm pacing have resulted in a smaller, more reliable implanted receiver, and a smaller, more compact transmitter with improved pacing parameter adjustment capabilities. Patients who previously were not candidates for dia­phragm pacing can now be successfully paced using customized transmitter settings.

Diaphragm pacing provides physiological respiratory function far superior to that provided by mechanical ventilators since the inhaled air is drawn into the lungs by the musculature, rather than being forced into the chest under mechanical pressure. The benefits of diaphragmatic pacing include:

Cost effectiveness because patients can live outside of hospitals and the cost of a ventilator and its disposables is eliminated.

Lower infection rate due to reduction in suctioning, elimination of external humidifier and ventilator circuits, and the possibility of tracheotomy tube removal (some patients have had their tracheotomy closed).

Improved venous return (negative, not positive pressure).

Normal breathing and speech.

Ease of eating and drinking.

Increased patient mobility.

Unobtrusive use due to the small size of external components and totally silent operation.

Ongoing experience with diaphragm pacing disproves some of the concerns expressed by early investigators in the field. Years of follow-up show that diaphragm pacing:

Provides a far lower cost of care and a much higher quality of life for ventilator dependent quadriplegic and sleep apneic patients

does not "burn out" nerves/muscles in normal operation.

can provide safe and effective bilateral pacing twenty-four hours per day.

can permit decannulation and discontinuation of tracheotomy tubes in selected patients.

can provide unilateral pacing where bilateral pacing is not possible due to destruction of the other phrenic nerve.

can provide safe operation near properly functioning microwave ovens and other equipment.

For Further Information call Avery Laboratories, Commack, Long Island Tel: 631-864-1600