Management and Treatment of Phrenic Nerve Dysfunction

Diagnostic Evaluation

Phrenic nerve stimulation techniques, including electrical stimulation (ES) and magnetic stimulation (MS), provide objective assessment of diaphragm function independent of patient effort 1
Measurement of twitch transdiaphragmatic pressure (Pdi,tw) following phrenic nerve stimulation provides a specific index of diaphragm strength 2

Diaphragm pacing generates breathing using the patient's own diaphragm as the respiratory pump and is considered optimal for ventilatory support during wakefulness in carefully selected patients, according to the American Thoracic Society 3
The system consists of battery-operated external transmitters that generate pulses transmitted via external antennae to subcutaneously implanted receivers connected to platinum phrenic nerve electrodes, as recommended by the American College of Chest Physicians 3
Bilateral implantation of phrenic nerve electrodes and diaphragm pacer receivers is recommended to achieve optimal ventilation, with a strength of evidence rated as high by the American Academy of Sleep Medicine 3
Patient selection criteria for diaphragm pacing include no or mild intrinsic lung disease, non-obese status, and intact phrenic nerve-diaphragm axis, as stated by the American College of Cardiology 3
Conservative use of diaphragm pacing is typically recommended (12-15 hours per day), with patients requiring continuous monitoring with pulse oximetry and PETCO2, according to the American Thoracic Society 3

Obstructive apnea can occur during sleep with diaphragm pacing due to lack of synchronous upper airway skeletal muscle contraction, and can be managed by adjusting pacer settings to lengthen inspiratory time and/or decrease the force of inspiration, as recommended by the American Academy of Sleep Medicine 3

For complete surgical resection of thymic tumors (which may affect the phrenic nerve), the standard approach involves complete surgical resection from the phrenic nerve to phrenic nerve laterally, as stated by the International Thymic Malignancy Interest Group 4

Patients with cardiac pacemakers can safely use diaphragm pacers as long as the cardiac pacemaker is bipolar, minimizing potential electromagnetic interference with the bilateral monopolar phrenic nerve electrodes, according to the Heart Rhythm Society 5
Implantable phrenic nerve stimulation is being investigated as a potential alternative approach for treating central sleep apnea in heart failure patients, with a strength of evidence rated as moderate by the European Society of Cardiology 6

After diaphragm pacer implantation, extensive experience in pacer management is required for biannual then annual comprehensive in-hospital evaluation, as recommended by the American College of Chest Physicians 5
The goal with diaphragm pacing is to minimize electrical stimulation while providing optimal ventilation and oxygenation, with a strength of evidence rated as high by the American Thoracic Society 5