An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome is a rare genetic disorder affecting ventilatory response to hypercapnia and/or hypoxemia. We describe a case of diaphragm pacing (DP) failure in a 38-year-old woman with congenital central hypoventilation syndrome who used DP as ventilatory support only during sleep for 24 years. Diagnostic evaluation began with examination of external DP equipment, but adjustment did not elicit adequate diaphragm contractions. Clinical evaluation and transtelephonic monitoring showed absent function of the right pacer and diminished function of the left pacer. The patient had surgical exploration of her internal DP components. The operation revealed that the right pacer receiver had significant circumferential calcium accumulation. After replacement of the receivers in subcutaneous pockets closer to the skin surface, robust diaphragm contractions bilaterally occurred with stimulation. This case suggests DP failure can result from development of calcification and increased distance from the skin surface to the receivers due to weight gain. CITATION: Kwon A, Lodge M, McComb JG, et al. An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome. J Clin Sleep Med. 2022;18(3):949-952.

Images: Polysomnographic artifacts in a child with congenital central hypoventilation syndrome.

NONE: Diaphragm pacing (DP), a modality of ventilatory support in children with congenital central hypoventilation syndrome, generates respiration using the patient's own diaphragm as the respiratory pump. We report a 14-year-old boy with congenital central hypoventilation syndrome who uses DP with an uncapped tracheostomy during sleep. Polysomnography to titrate DP settings identified artifacts occurring in regular intervals coinciding with the onset of inspiration during all sleep stages in several channels including legs, snore, and electrocardiogram. Clinicians interpreting polysomnograms performed during DP should become familiar with the multichannel artifacts due to DP impulses. We also identified that our patient was hyperventilated on home DP settings that led to adjustment of DP settings during the polysomnogram to achieve optimal oxygenation and ventilation. Our case also highlights the utility of polysomnography to ensure optimal gas exchange during sleep in children with congenital central hypoventilation syndrome using DP.

Positional impairment of gas exchange during diaphragm pacing alleviated by increasing amplitude settings in congenital central hypoventilation syndrome.

None: Diaphragm pacing (DP) by phrenic nerve stimulation is a modality of chronic ventilatory support in individuals with congenital central hypoventilation syndrome (CCHS). We report a 9-year-old girl with CCHS who uses DP without tracheostomy during sleep. Her parents report hypoxemia and hypercapnia related to positional changes of the body during sleep requiring frequent adjustment of pacer settings. Overnight polysomnography was performed to titrate DP settings that showed adequate gas exchange in the supine position, but intermittent hypoxemia and hypercapnia were noted in the left decubitus position without obstructive sleep apnea occurring. Subsequently, the DP amplitude settings were increased during polysomnography, thereby identifying and treating positional hypoxemia and hypercapnia in various body positions. Our case emphasizes the importance of polysomnography in children with CCHS using DP to monitor for sleep-disordered breathing and titration of DP settings to achieve optimal oxygenation and ventilation with different body positions during sleep.

Airway Obstruction during Sleep due to Diaphragm Pacing Precludes Decannulation in Young Children with CCHS.

Children with congenital central hypoventilation syndrome (CCHS) have a PHOX2B mutation-induced control of breathing deficit necessitating artificial ventilation as life support. A subset of CCHS families seek phrenic nerve-diaphragm pacing (DP) during sleep with the goal of tracheal decannulation. Published data regarding DP during sleep as life support in the decannulated child with CCHS and related airway dynamics in young children are limited. We report a series of 3 children, ages 3.3-4.3 years, who underwent decannulation. Sleep endoscopy performed during DP revealed varied (oropharynx, supraglottic, glottic, etc.) levels of complete airway obstruction despite modification of pacer settings. Real-time analysis of end tidal CO2 and SpO2 confirmed inadequate gas exchange. Because the families declined re-tracheostomy, all 3 patients rely on noninvasive mask ventilation as a means of life support while asleep. These results emphasize the need for extreme caution in proceeding with tracheal decannulation in young children with CCHS who expect to use DP during sleep as life support. Parents and patients should anticipate that they will depend on noninvasive mask ventilation (rather than DP) during sleep after undergoing decannulation. This information may improve management and guide expectations regarding potential decannulation in young paced children with CCHS.

[Diaphragm pacemaker: alternative for long-term ventilatory support; 5 years later]. / Diafragmapacemaker: alternatief voor chronische beademing.

Currently, more than 3000 patients in the Netherlands receive long-term ventilatory support. In the majority of patients, long-term ventilatory support leads to increased survival without any complications. Diaphragm pacing with an external pacemaker (diaphragm pacing system, DPS) seems an attractive alternative for long-term ventilatory support by mask or tracheostomy. Scientific research has since shown that DPS is effective in patients with high cervical paraplegia. In addition, patients with congenital central hypoventilation syndrome are also eligible for DPS. Patients with diaphragm paralysis are a new group of patients who may be eligible for DPS. Two European studies have shown that DPS should not be used in patients with amyotrophic lateral sclerosis. In our experience, patients are no longer completely dependent on a ventilator or may even be able to discontinue using one if the procedure was successful. In the Netherlands, as far as we know, the technique is only used at the University Medical Center Groningen.

Perioperative anesthetic management of children with congenital central hypoventilation syndrome and rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation undergoing thoracoscopic phrenic nerve-diaphragm pacemaker implantation.

BACKGROUND: Congenital Central Hypoventilation Syndrome and Rapid-Onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation are rare neurocristopathies characterized by autonomic dysregulation including bradyarrhythmias, abnormal temperature control, and most significantly, abnormal control of breathing leading to tracheostomy and ventilator dependence as life support. Surgical advancements have made phrenic nerve-diaphragm pacemakers available, to eliminate the tether to a mechanical ventilator for 12-15 hours each day. The thoracoscopic approach to implantation has allowed for a less invasive approach which may have implications for pain control and recovery time. However, thoracoscopic implantation of these devices presents several challenges to the anesthesiologist in these complex ventilator-dependent patients, including, but not limited to, sequential lung isolation, prevention of hypothermia, and management of arrhythmias. Postoperative challenges may also include strategies to treat hemodynamic instability, managing the ventilator following lung derecruitment, and providing adequate pain control. AIMS: We aimed to describe the anesthetic management of Congenital Central Hypoventilation Syndrome and Rapid-Onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation patients undergoing thoracoscopic phrenic nerve-diaphragm pacemaker implantation and the nature and incidence of perioperative complications. METHODS: A retrospective chart review was performed of 14 children with Congenital Central Hypoventilation Syndrome and Rapid-Onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation undergoing phrenic nerve-diaphragm pacemaker implantation at a single academic pediatric hospital between 2009 and 2017. Demographic information, intraoperative management, and perioperative complications were analyzed from patient records. RESULTS: Twelve of 14 patients (86%) underwent an inhalational induction via tracheostomy. Lung isolation was achieved via fiberoptic guidance of a single lumen endotracheal tube sequentially into the right or left mainstem bronchi for 12 patients (86%). Double lumen endotracheal tubes were utilized in two patients (7%) and bronchial blockers in two patients (7%) for lung isolation. Anesthesia was maintained using a balanced technique of volatile agents (sevoflurane/isoflurane) and opioids (fentanyl). Bradyarrhythmias developed in six patients (43%) during surgery, 5 (36%) responded to anticholinergics and one patient (7%) required backup cardiac pacing using a previously implanted bipolar cardiac pacemaker. Intraoperative hypothermia (<35.5°C) was present in five patients (36%) despite the use of warming devices. Hypercarbia (>50 mm Hg) during lung isolation was present in eight patients (57%) and hemoglobin desaturation (<90%) in four patients (29%). Postoperatively, oxygen desaturation was a common complication with nine patients (64%) requiring supplemental oxygen administration via mechanical ventilator or manual bag ventilation. Opioids via patient-controlled analgesia devices (12 patients, 86%) or intermittent injection (two patients, 14%) were administered to all patients for postoperative pain control. Phrenic nerve-diaphragm pacemaker placement was successful thoracoscopically in all patients with no perioperative mortality. CONCLUSION: The main anesthetic challenges in patients with Congenital Central Hypoventilation Syndrome and Rapid-Onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation include hemodynamic instability, the propensity to develop hypothermia, hypercarbia/hypoxemia, and the need to perform bilateral sequential lung isolation requisite to the thoracoscopic implantation technique. Most anesthetic agents can be used safely in these patients; however, adequate knowledge of the susceptibility to complications, coupled with adequate preparation and understanding of the innate disease characteristics, are necessary to treat anticipated complications.

Alternative methods of lung isolation in cases of pediatric bilateral thoracoscopic surgery.

We compare airway management and lung isolation methods in two pediatric cases of congenital central hypoventilation syndrome undergoing bilateral throacoscopic phrenic-nerve-stimulator surgery. One child received lung isolation using a 7Fr bronchial blocker in conjunction with a 6.0 cuffed endotracheal tube; and the second received a technique of endobronchial intubation using a 3.5 microcuffed tube via the tracheostomy stoma in conjunction with 5.0 cuffed endotracheal intubation; a technique previously undescribed in pediatric patients.

Phrenic Nerve Stimulation: Technology and Clinical Applications.

Phrenic nerve stimulation is a technique used to reanimate the diaphragm of patients with central nervous system etiologies of respiratory insufficiency. Current clinical indications include congenital central hypoventilation syndrome, spinal cord injury above C4, brain stem injury, and idiopathic severe sleep apnea. Presurgical evaluation ensures proper patient selection by validating the intact circuit from the phrenic nerve through alveolar oxygenation. The procedure involves placing leads around the phrenic nerves bilaterally and attaching these leads to radio receivers in a subcutaneous pocket. The rate and amplitude of the current is adjusted via an external radio transmitter. After implantation, each patient progresses through a conditioning phase that strengthens the diaphragm and progressively provides independence from the mechanical ventilator. Studies indicate that patients and families experience an improved quality of life and are satisfied with the results. Phrenic nerve stimulation provides a safe and effective means for reanimating the diaphragm for certain patients with respiratory insufficiency, providing independence from mechanical ventilation.

Hypocretin Deficiency Associated with Narcolepsy Type 1 and Central Hypoventilation Syndrome in Neurosarcoidosis of the Hypothalamus.

We report a case of a 53-year-old man presenting with depressed alertness and severe excessive sleepiness in the setting of neurosarcoidosis. Neuroimaging demonstrated hypothalamic destruction due to sarcoidosis with a CSF hypocretin level of 0 pg/mL. The patient also experienced respiratory depression that presumably resulted from hypocretin-mediated hypothalamic dysfunction as a result of extensive diencephalic injury. This is a novel case, demonstrating both hypocretin deficiency syndrome, as well as respiratory dysfunction from destruction of hypocretin neurons and extensive destruction of key diencephalic structures secondary to the underlying neurosarcoidosis.

Diaphragm Pacing without Tracheostomy in Congenital Central Hypoventilation Syndrome Patients.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is a rare disorder affecting central control of breathing. Thus, patients require lifelong assisted ventilation. Diaphragm pacing (DP) may permit decannulation in those who are ventilator dependent only during sleep. OBJECTIVE: The purpose of this study is to determine if patients with CCHS can be successfully ventilated by DP without tracheostomy. METHODS: We reviewed the records of 18 CCHS patients (mean age 19.5 ± 10.1 years; 44% female) who were ventilated by DP only during sleep. RESULTS: Prior to diaphragm pacer implantation surgery, 14 CCHS patients had been using home portable positive pressure ventilation (PPV) via tracheostomy, 1 had been on PPV via endotracheal tube, and 3 had been using noninvasive PPV (NPPV). Of the patients with tracheostomy prior to DP (n = 15), 11 (73%) were decannulated and ventilated successfully by DP without tracheostomy. Of all the patients reviewed (n = 18), 13 (72%) were successfully ventilated by DP without tracheostomy. Obesity prevented successful DP without tracheostomy in 1 patient, and upper airway obstruction prevented success in another patient. Snoring and/or obstructive apneas were present in some patients, but they were improved by diaphragm pacer changes, adenotonsillectomy, and/or use of nasal steroids. CONCLUSIONS: DP without tracheostomy can be successfully achieved in patients with CCHS. Snoring and obstructive apneas, when present, can be managed by diaphragm pacer changes and medical therapies. Obesity can pose a challenge to successful DP.

Thoracoscopic placement of phrenic nerve pacers for diaphragm pacing in congenital central hypoventilation syndrome.

PURPOSE: Congenital central hypoventilation syndrome (CCHS), or Ondine's curse, is a rare disorder affecting central respiratory drive. Patients with this disorder fail to ventilate adequately and require lifelong ventilatory support. Diaphragm pacing is a form of ventilatory support which can improve mobility and/or remove the tracheostomy from CCHS patients. Little is known about complications and long-term outcomes of this procedure. METHODS: A single-center retrospective review was performed of CCHS patients undergoing placement of phrenic nerve electrodes for diaphragm pacing between 2000 and 2012. Data abstracted from the medical record included operation duration, ventilation method, number of trocars required, and postoperative and pacing outcomes. RESULTS: Charts of eighteen patients were reviewed. Mean surgical time was 3.3±0.7 hours. In all cases except one, three trocars were utilized for each hemithorax, with no conversions to open procedures. Five patients (27.8%) experienced postoperative complications. The mean ICU stay was 4.3±0.5 days, and the mean hospital stay is 5.7±0.3days. Eleven patients (61.1%) achieved their daily goal pacing times within the follow-up period. CONCLUSIONS: Thoracoscopic placement of phrenic nerve electrodes for diaphragmatic pacing is a safe and effective treatment modality for CCHS. Observed complications were temporary, and the majority of patients were able to achieve pacing goals.

Airway obstruction in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is the failure of the autonomic system to control adequate ventilation while asleep with preserved ventilatory response while awake. We report a case of a patient with CCHS who presented with intrathoracic and extrathoracic airway obstruction after tracheostomy tube decannulation and phrenic nerve pacer placement. Nocturnal polysomnography (NPSG) revealed hypoxia, hypercapnia and obstructive sleep apnoea, which required bilevel positive airway pressure titration. Airway endoscopy demonstrated tracheomalacia and paretic true vocal cords in the paramedian position during diaphragmatic pacing. Laryngeal electromyography demonstrated muscular electrical impulses that correlated with diaphragmatic pacer settings. Thus, we surmise that the patient's upper and lower airway obstruction was secondary to diaphragmatic pacer activity. Thorough airway evaluation, including NPSG and endoscopy, may help identify the side effects of diaphragmatic pacing, such as airway obstruction, in patients with CCHS.

Reversal of pulmonary hypertension after diaphragm pacing in an adult patient with congenital central hypoventilation syndrome.

INTRODUCTION: Patients with the congenital central hypoventilation syndrome (CCHS) suffer from life-threatening hypoventilation when asleep, making them dependent on mechanical ventilation (MV) at night or during naps. State-of-art respiratory management consists of intermittent positive-pressure ventilation via a tracheotomy or mask. In some patients hypoventilation is permanent, in which case ventilatory support must be extended to the waking hours. Diaphragm pacing can prove useful in such situations. 
 METHODS AND RESULTS: This report describes the case of a 26-year-old woman with CCHS in whom failure to achieve adequate MV led to life-threatening pulmonary hypertension (PH), with a systolic pulmonary artery pressure (PAP) of 80 mmHg and right ventricular hypertrophy, despite optimization of all possible measures and despite extensive therapeutic education efforts. Diaphragm pacing using laparoscopically implanted intradiaphragmatic phrenic nerve stimulation electrodes corrected alveolar hypoventilation and lastingly reversed PH (systolic PAP below 40 mmHg after 2 months, sustained after 2 years). Diaphragm pacing induced shoulder pain, however, involving the chronic use of analgesics. The pacing had to be stopped for tolerance reasons after two years, leading to PH worsening and the need for diurnal MV. 
 CONCLUSIONS: Diaphragm pacing appears likely effective to restore alveolar ventilation and reverse PH in adult CCHS patients.

Vagal nerve stimulator placement for medically refractory seizures in a child treated with phrenic nerve pacing for congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is a rare, idiopathic disorder characterized by a failure of automatic respiration. Abnormalities such as seizure disorder, failure to thrive, and Hirschsprung disease have been associated with CCHS. In this report, the authors discuss the use of vagal nerve stimulation (VNS) to treat a medically refractory seizure disorder in a child who had previously undergone placement of bilateral phrenic nerve stimulators for treatment of CCHS. Concomitant use of phrenic and vagal nerve stimulators has not previously been reported in the literature. No adverse reactions were noted with both devices working. Diaphragmatic pacing (DP) was clinically unaffected by VNS. The patient experienced a marked reduction in seizure frequency and severity following vagal nerve stimulator placement. Based on this case, the authors conclude that VNS is a potentially safe and efficacious treatment option for seizure disorder associated with CCHS in patients undergoing DP.

An official ATS clinical policy statement: Congenital central hypoventilation syndrome: genetic basis, diagnosis, and management.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is characterized by alveolar hypoventilation and autonomic dysregulation. PURPOSE: (1) To demonstrate the importance of PHOX2B testing in diagnosing and treating patients with CCHS, (2) to summarize recent advances in understanding how mutations in the PHOX2B gene lead to the CCHS phenotype, and (3) to provide an update on recommendations for diagnosis and treatment of patients with CCHS. METHODS: Committee members were invited on the basis of their expertise in CCHS and asked to review the current state of the science by independently completing literature searches. Consensus on recommendations was reached by agreement among members of the Committee. RESULTS: A review of pertinent literature allowed for the development of a document that summarizes recent advances in understanding CCHS and expert interpretation of the evidence for management of affected patients. CONCLUSIONS: A PHOX2B mutation is required to confirm the diagnosis of CCHS. Knowledge of the specific PHOX2B mutation aids in anticipating the CCHS phenotype severity. Parents of patients with CCHS should be tested for PHOX2B mutations. Maintaining a high index of suspicion in cases of unexplained alveolar hypoventilation will likely identify a higher incidence of milder cases of CCHS. Recommended management options aimed toward maximizing safety and optimizing neurocognitive outcome include: (1) biannual then annual in-hospital comprehensive evaluation with (i) physiologic studies during awake and asleep states to assess ventilatory needs during varying levels of activity and concentration, in all stages of sleep, with spontaneous breathing, and with artificial ventilation, and to assess ventilatory responsiveness to physiologic challenges while awake and asleep, (ii) 72-hour Holter monitoring, (iii) echocardiogram, (iv) evaluation of ANS dysregulation across all organ systems affected by the ANS, and (v) formal neurocognitive assessment; (2) barium enema or manometry and/or full thickness rectal biopsy for patients with a history of constipation; and (3) imaging for neural crest tumors in individuals at greatest risk based on PHOX2B mutation.

Diaphragm pacers as a treatment for congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome is a rare syndrome present from birth, and is defined as the failure of automatic control of breathing. All patients with congenital central hypoventilation syndrome require life-long ventilatory support during sleep, although approximately a third of patients require ventilatory support 24 h per day. Diaphragm pacers offer a modality of ventilatory support that affords congenital central hypoventilation syndrome patients with maximal mobility for full-time ventilatory patients, and they may allow for a more normal lifestyle in the appropriate patient. They may permit tracheostomy decannulation in those requiring only support during sleep. Diaphragm pacing entails surgical placement of an electrode onto the phrenic nerve, connected to a subcutaneous receiver. There is an external battery-operated transmitter and antenna placed on the skin over the receiver. The transmitter emits energy, similar to radio transmission, which is converted into an electrical current by the receiver. This stimulates the phrenic nerve resulting in a diaphragmatic contraction. Settings on the transmitter include respiratory rate and electrical voltage, and are adjusted to give enough tidal volume to allow for adequate oxygenation and ventilation. Therefore, diaphragm pacing is an attractive alternative mode of mechanically assisted ventilation for many patients with congenital central hypoventilation syndrome.

Diaphragmatic pacemaker failure in congenital central hypoventilation syndrome: a tale of two twiddlers.

Two patients with congenital central hypoventilation syndrome (CCHS) experienced phrenic nerve pacer failure due to deliberate manipulation of the internal receiver implant ("twiddling"). The patients, aged 7 and 12 years, presented with repeated episodes of pacer failure associated with local pain over a period of 18 months. They had progressively coiled the pacing wires to the point of breakage, which only became apparent at surgery. The breaks were not recognized radiologically, although in retrospect progressive twisting of the wires was evident on serial chest radiographs. Both patients required replacement of the internal receivers under general anesthesia. We recommend that the chest radiograph that is undertaken to investigate the cause of pacer dysfunction include the internal receiver. A plain chest radiograph that demonstrates progressive coiling of the subcutaneous pacing wire should raise suspicion of pacer wire breakage regardless of the patient's age.

Congenital central hypoventilation syndrome treated with diaphragm pacing.

Congenital central hypoventilation syndrome was diagnosed in an infant who since birth had shallow respiration and CO2 retention during sleep, absent ventilatory response to hypercarbia, and no underlying disease or trauma to account for the symptoms. Diaphragm pacing was started at the age of 8 1/2 months and has been successfully carried out at home, guided by end-tidal CO2 monitoring. After 22 months of home treatment, at the age of two years 9 months, linear growth and psychomotor development are progressing normally, while previous symptoms of cor pulmonale have not progressed.