Diaphragmatic pacing helps individuals breathe independently. This treatment involves a surgically implanted system that assists the body’s natural breathing process. Much like a cardiac pacemaker regulates the heart’s rhythm, a diaphragmatic pacemaker helps manage the contractions of the diaphragm, the primary muscle involved in breathing. This technology offers an alternative to continuous mechanical ventilation, aiming to restore a more natural respiratory function for patients.
The Mechanism of Pacing the Diaphragm
Breathing relies on the diaphragm, a large, dome-shaped muscle beneath the lungs, and the phrenic nerves that transmit signals to it. These nerves, originating from cervical spinal cord segments C3 to C5, send impulses that cause the diaphragm to contract, pulling air into the lungs for inspiration. When these impulses cease, the diaphragm relaxes, allowing air to be expelled from the lungs during exhalation.
A diaphragmatic pacing system intervenes when these signals are disrupted or absent. The system’s electrodes are surgically positioned either directly onto the diaphragm muscle or around the phrenic nerves. These electrodes are connected to an implanted receiver, which is placed under the skin in the chest or abdomen. An external transmitter, worn by the patient, wirelessly sends controlled electrical impulses through an antenna placed over the receiver. These electrical signals then stimulate the phrenic nerves, prompting the diaphragm to contract rhythmically and facilitate breathing.
Qualifying Conditions for Treatment
Patients considered for diaphragmatic pacing have conditions that impair their ability to breathe without assistance but leave their diaphragm and phrenic nerves functional. A primary group includes individuals with high-level spinal cord injuries, particularly those affecting the C1 or C2 cervical segments. In these cases, the brain’s signals for breathing cannot reach the phrenic nerves due to the injury, leading to ventilator dependence.
The treatment is also utilized for patients with central alveolar hypoventilation syndrome. This rare condition causes the diaphragm to stop working effectively, especially during sleep. For individuals with Amyotrophic Lateral Sclerosis (ALS), diaphragmatic pacing has been explored, though patient selection is important due to varying outcomes.
The Implantation Surgery
The implantation of a diaphragmatic pacing system involves several components placed within the body and external devices for control. Internally, electrodes are positioned on or near the phrenic nerves, and these connect to a receiver implanted just beneath the skin. The external components include an antenna, which is taped to the skin over the receiver, and a portable, battery-operated transmitter that generates the electrical signals.
The surgical procedure is performed using minimally invasive techniques, such as laparoscopy or video-assisted thoracoscopic surgery (VATS). During laparoscopy, small incisions are made in the abdomen for electrode placement on the diaphragm. Similarly, VATS involves small incisions in the chest for electrode placement around the phrenic nerve. These techniques allow for precise placement while minimizing surgical trauma, with the entire procedure lasting around 1.5 to 2 hours.
Life After Implantation
Following the implantation surgery, patients begin a process known as diaphragm conditioning or reconditioning. This involves gradually strengthening the diaphragm muscle, which may have weakened from disuse while on a ventilator. Initially, pacing sessions might be short, with the duration slowly increasing over time as the diaphragm adapts and gains strength. This progressive approach helps the muscle build endurance and prevents fatigue.
The goal for many patients is to gradually wean off the mechanical ventilator. Achieving independence from a ventilator can improve a patient’s quality of life, offering increased mobility and the ability to speak and smell normally, which is difficult with a tracheostomy and mechanical ventilator. Additionally, patients may experience a reduced risk of respiratory infections compared to those on traditional ventilation. Daily management involves attaching the external antenna and operating the portable transmitter to maintain the pacing schedule.