• The portable positive pressure ventilator is the most common method of providing home mechanical ventilation in CCHS.
• A tracheostomy is required for positive pressure ventilator access. A tracheostomy tube smaller than the airway caliber may reduce the likelihood of tracheomalacia, allow for a leak adequate to use the Passy-Muir one-way speaking valve while off the ventilator, and allow for a margin of safety if the tube becomes occluded.
• Signs that a tracheostomy tube size may need to be increased are sometimes subtle but include difficulty achieving adequate gas exchange and a visible plateau on PETCO2 monitoring, having to increase ventilator settings to levels above those of other similar-aged children, more frequent pneumonias, and an audible air leak. A spare tracheostomy tube is necessary as a back-up at all times and should be carried with the Ambu bag for any travel outside of the home.
• Using the home ventilator in a pressure plateau mode or pressure control mode may compensate for a small leak, although the use of a tight-to-the-shaft cuffed tracheostomy tube may be necessary with some home ventilators.
• Ideally, a second ventilator in the home for those individuals with CCHS who rely on mechanical ventilation, regardless of the duration of hours of use each day, may prevent emergency admission in the event of ventilator failure.
• A ventilator circuit is required to deliver air from a positive pressure ventilator to the patient through a heated humidification system connected to the tracheostomy with a swivel adapter. Two to three circuits are generally provided for home care. Circuits should be cleaned and changed routinely.

• Bilevel ventilators are smaller, less expensive, and generally easier to use than conventional ventilators, but they are not designed for life support.
• Inspiratory positive airway pressure and expiratory positive airway pressure can be adjusted independently (difference is proportional to tidal volume), maintaining a large inspiratory positive airway pressure to expiratory positive airway pressure difference as tidal volume increases linearly, up to approximately 14 cm H2O.
• Only the timed mode guarantees breath delivery in children who cannot generate adequate large spontaneous breaths to trigger the ventilator.
• Bilevel ventilation should not be used outside of sleep time as the mask interferes with daily activities and social interaction, and the risk of skin breakdown increases.
• Historically, mask ventilation has been associated with mid-face hypoplasia when introduced from infancy or early childhood, however newer mask models may be less impactful on mid-face hypoplasia issues. A pediatric plastic surgeon and orthodontist/oral surgeon should closely follow any child using mask ventilation. Children may require intubation and more sophisticated ventilatory support during acute respiratory illnesses.
• The major benefit of bilevel ventilation is that a tracheostomy is not required, although successful management with bilevel ventilation is most effective in older children and adults with the milder CCHS phenotypes.
• Bilevel positive airway pressure ventilation should not be used with a tracheostomy. If a child has a tracheostomy, ventilation is much more reliable and effective using a positive pressure ventilator than using bilevel ventilation.
• A number of children with CCHS have been successfully transitioned from positive pressure ventilation via tracheostomy to bilevel positive airway pressure ventilation by mask or nasal prongs after 6 to 8 years of age.

• Diaphragm pacing generates breathing using the child’s own diaphragm.
• Currently there are two diaphragm pacing systems currently available for treating CCHS.  These systems all stimulate the phrenic nerve causing the diaphragm to move and ventilation to occur without the use of a ventilator or other external ventilation system.
• The Atrostim (not available in the USA) and Avery systems stimulate the phrenic nerve by direct stimulation of the nerve and may be implanted via the minimally invasive neck approach or transthoracically.
• The Atrostim and Avery (Figure 1) systems have electrodes placed in intimate contact with the phenic nerve either through the neck or transthoracically (Figure 2).  The electrode is attached to a wire placed under the skin and connected to a small receiver also placed under the skin over the chest.  When in use, a circular antenna connected to an external power source is placed over the receiver (Figure 3).  The antenna delivers radiofrequency energy through the skin to the implanted receiver which converts the energy to a small electrical current which periodically stimulates the phrenic nerve.
• Bilateral implantation of phrenic nerve electrodes and diaphragm pacer receivers is recommended to achieve optimal ventilation in children.
• While most CCHS patients use phrenic nerve stimulation only at night. a number of patients use the system 24/7.  For patients who use the diaphragm pacer during sleep time only, the aim is to minimize the need for mechanical ventilator and potentially remove the tracheostomy.
• Obstructive apnea can be a complication of diaphragm pacing during sleep in the decannulated individual as synchronous upper airway skeletal muscle contraction does not occur with paced inspiration. This may be overcome by adjusting settings on the pacers to lengthen inspiratory time and/or decrease the force of inspiration.
• Patients with CCHS using Atrostim or Avery diaphragm pacing should have spare antennae in the home, as these components are disposable and need replacement (typically every 6 months).  It is recommended that all individuals with CCHS who rely on diaphragm pacing have a back-up mode of ventilation available in case of pacer failure.
• Diaphragm pacer implantation of the internal components (receivers, connecting wires, and phrenic nerve electrodes) may be done via the minimally invasive cervical approach (Atrostim or Avery system)  as an outpatient procedure.  Transthoracic placement of the Atrostim or Avery system usually requires at least overnight hospital observation.
• Diaphragm pacing may significantly improve the quality of life and significantly reduce the cost of caring for CCHS patients.

  Figure 1 (courtesy of Avery Biomedical Devices)

  Figure 2 (courtesy of Avery Biomedical Devices)

  Figure 3 (courtesy of Avery Biomedical Devices)

There are three modes of delivering a negative pressure in order to perform breathing: 1) the chest shell, 2) the Vest, 3) a Port-a-lung. For all three types of NPV negative pressure is delivered to the chest and abdomen to cause an inspiration as the negative pressure causes a suction of the air into the lungs. This mode is infrequently, if ever, used any more.