Diaphragmatic pacemaker
Encyclopedia
A diaphragmatic pacemaker, in medicine
, is a surgically-implanted device used to help patients breathe following complications from spinal cord injuries
. The device works through pacing
of the diaphragm
.
by electrical stimulation
(pacing) of the phrenic nerve
. The pacing is accomplished via electrode
s surgically
implanted into the diaphragm, which is controlled by the phrenic nerve.
Diaphragm pacing stimulates a normal breath response as follows: when an electrical current is passed through the electrodes, the diaphragm contracts, expanding the chest cavity, causing air to be sucked into the lung
s (inspiration
). When the nerve is not stimulated, the diaphragm relaxes and air moves out of the lungs (expiration
).
that cut across (transect) the cervical
spinal cord
high in the neck and result in paralysis
of all four limb
s (tetraplegia) and respiratory failure
which require constant mechanical ventilatory support. For the procedure to work, the function of the phrenic nerve must be normal.
Diaphragm pacing originally required a surgical opening of the chest cavity
(thoracotomy
) to implant
the electrodes. It is now done by laparoscopy
through small openings in the abdominal cavity. 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.
The actor Christopher Reeve
, who was paralyzed
and on a respirator
after fracturing his neck in a horseback riding accident
, underwent the procedure in 2003.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, is a surgically-implanted device used to help patients breathe following complications from spinal cord injuries
Spinal cord injury
A spinal cord injury refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence...
. The device works through pacing
Pacing
Pacing may refer to:* Pacing , a horse gait used in Standardbred horse races* Pacing, the even spreading out of athletes' strength in longer-distance track and field and swimming races, so that they don't burn themselves out...
of the diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...
.
Mechanism
In patients with a diaphragmatic pacemaker, their breathing is helped by setting the respiratory rateRespiratory rate
Respiratory rate is also known by respiration rate, pulmonary ventilation rate, ventilation rate, or breathing frequency is the number of breaths taken within a set amount of time, typically 60 seconds....
by electrical stimulation
Functional electrical stimulation
Functional electrical stimulation is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury , head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with...
(pacing) of the phrenic nerve
Phrenic nerve
The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves in humans....
. The pacing is accomplished via electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
s surgically
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
implanted into the diaphragm, which is controlled by the phrenic nerve.
Diaphragm pacing stimulates a normal breath response as follows: when an electrical current is passed through the electrodes, the diaphragm contracts, expanding the chest cavity, causing air to be sucked into the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s (inspiration
Inhalation
Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....
). When the nerve is not stimulated, the diaphragm relaxes and air moves out of the lungs (expiration
Expiration
Expiration is an independent feature film written, directed and starring Gavin Heffernan. It was the winner of the Grand Jury Prize and Best Film at the Canadian Filmmakers' Festival....
).
Procedure
This procedure was approved in Europe under CE mark and the US in 2008. It is being tested in patients with injuriesInjury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...
that cut across (transect) the cervical
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...
spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
high in the neck and result in paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
of all four limb
Limb (anatomy)
A limb is a jointed, or prehensile , appendage of the human or other animal body....
s (tetraplegia) and respiratory failure
Respiratory failure
The term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
which require constant mechanical ventilatory support. For the procedure to work, the function of the phrenic nerve must be normal.
Diaphragm pacing originally required a surgical opening of the chest cavity
Thoracic cavity
The thoracic cavity is the chamber of the human body that is protected by the thoracic wall ....
(thoracotomy
Thoracotomy
Thoracotomy is an incision into the pleural space of the chest. It is performed by a surgeon, and, rarely, by emergency physicians, to gain access to the thoracic organs, most commonly the heart, the lungs, the esophagus or thoracic aorta, or for access to the anterior spine such as is necessary...
) to implant
Implant
Implant can refer to:*Implant , or specifically:**Brain implant**Breast implant**Buttock implant**Cochlear implant**Contraceptive implant**Dental implant**Mini dental implant**Extraocular implant**Fetal tissue implant...
the electrodes. It is now done by laparoscopy
Laparoscopy
Laparoscopy is an operation performed in the abdomen or pelvis through small incisions with the aid of a camera...
through small openings in the abdominal cavity. Patients undergo laparoscopic implantation of electrodes in the muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
of the diaphragm and initial electrical stimulation. Following a recovery
Healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....
period of a week or so, diaphragm pacing is initiated. Wires
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...
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
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
of electrode stimulation is gradually increased until full-time diaphragm pacing is achieved.
The actor Christopher Reeve
Christopher Reeve
Christopher D'Olier Reeve was an American actor, film director, producer, screenwriter, author and activist...
, who was paralyzed
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
and on a respirator
Respirator
A respirator is a device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, or gases. Respirators come in a wide range of types and sizes used by the military, private industry, and the public...
after fracturing his neck in a horseback riding accident
Accident
An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...
, underwent the procedure in 2003.