DOCTOR'S VIEW ARCHIVE
Medical Author: Frederick Hecht, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
Online medical dictionaries have their limitations but one salient advantage they have over the standard print ones is nimbleness. A medical dictionary such as MedicineNet's MedTerms can be ever so nimble. It can incorporate a new word or term with alacrity.
Let's take one case in point. Yesterday (March 11, 2003) we read an article in The New York Times titled "Experiment Aims to Allow Paralyzed Actor to Breathe on Own." We found the story very moving. The paralyzed actor is Christopher Reeve. He recently had a new procedure done, which may free him from total dependence on a respirator.
The procedure is called diaphragm pacing. I had never heard of it but I thought it would be of interest to our viewers. So, after researching it, I created the following entry for MedTerms:
Diaphragm pacing: A procedure to help patients with spinal cord injuries to breathe. Their breathing is helped by setting the respiratory rate by electrical stimulation (pacing) of the phrenic nerve. The pacing is accomplished via electrodes surgically implanted into the diaphragm, which is innervated by the phrenic nerve.
This procedure is currently experimental. It is being tested in patients with injuries that cut across (transect) the cervical spinal cord high in the neck and result in paralysis of all four limbs (tetraplegia) and respiratory failure requiring chronic mechanical ventilatory support. For the procedure to work, the function of the phrenic nerve must be normal.
Diaphragm pacing originally required surgery opening the chest cavity (thoracotomy) to implant the electrodes. It is now done by laparoscopy through small openings in the chest. Patients undergo laparoscopic implantation of electrodes in the muscle of the diaphragm and initial electrical stimulation. Following a recovery period of a week or so, diaphragm pacing is initiated. Wires from the electrodes in the diaphragm run to and from a control box worn outside the body. The pacing is performed according to a reconditioning program in which the duration and frequency of electrode stimulation is gradually increased until full-time diaphragm pacing is achieved.
How does diaphragm pacing work to help breathing? When the electrodes are stimulated by current, the diaphragm contracts and air is sucked into the lungs (inspiration). When the nerve is not stimulated, the diaphragm relaxes and air moves out of the lungs (expiration).
The actor Christopher Reeve, who was paralyzed and on a respirator after fracturing his neck in a riding accident, underwent the procedure in 2003. The procedure is also known as electrophrenic respiration (abbreviated EPR) and diaphragmatic or phrenic pacing.
This is one of many new terms that an online resource like MedTerms can nimbly incorporate and make available to enrich your and our reading about medicine today.