Assessing Efficacy of High-Frequency Chest Wall Oscillation in Patients With Familial Dysautonomia

Respiratory care in familial dysautonomia: Systematic review and expert consensus recommendations

BACKGROUND

Familial dysautonomia (Riley-Day syndrome, hereditary sensory autonomic neuropathy type-III) is a rare genetic disease caused by impaired development of sensory and afferent autonomic nerves. As a consequence, patients develop neurogenic dysphagia with frequent aspiration, chronic lung disease, and chemoreflex failure leading to severe sleep disordered breathing. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of respiratory disorders in familial dysautonomia.

METHODS

We performed a systematic review to summarize the evidence related to our questions. When evidence was not sufficient, we used data from the New York University Familial Dysautonomia Patient Registry, a database containing ongoing prospective comprehensive clinical data from 670 cases. The evidence was summarized and discussed by a multidisciplinary panel of experts. Evidence-based and expert recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Recommendations were formulated for or against specific diagnostic tests and clinical interventions. Diagnostic tests reviewed included radiological evaluation, dysphagia evaluation, gastroesophageal evaluation, bronchoscopy and bronchoalveolar lavage, pulmonary function tests, laryngoscopy and polysomnography. Clinical interventions and therapies reviewed included prevention and management of aspiration, airway mucus clearance and chest physical therapy, viral respiratory infections, precautions during high altitude or air-flight travel, non-invasive ventilation during sleep, antibiotic therapy, steroid therapy, oxygen therapy, gastrostomy tube placement, Nissen fundoplication surgery, scoliosis surgery, tracheostomy and lung lobectomy.

CONCLUSIONS

Expert recommendations for the diagnosis and management of respiratory disease in patients with familial dysautonomia are provided. Frequent reassessment and updating will be needed.

The Impact of High-Frequency Chest Wall Oscillation on Healthcare Use in Patients with Neuromuscular Diseases

RATIONALE

People with neuromuscular disease frequently have difficulty clearing pulmonary secretions, which leads to pneumonia and respiratory failure. High-frequency chest wall oscillation (HFCWO) is one intervention used to facilitate secretion clearance.

OBJECTIVES

The objective of this study was to determine if HFCWO therapy leads to improved outcomes as measured by lower healthcare use for patients who have a chronic neuromuscular disease.

METHODS

We performed a cohort study comparing healthcare claims before and after initiation of HFCWO. Data were obtained from two large databases of commercial insurance claims. Study subjects were commercial insurance members with an International Classification of Diseases, Ninth Revision, code for a neuromuscular disease and a claim for HFCWO between 2007 and 2011. The study included both children and adults.

MEASUREMENTS AND MAIN RESULTS

There were 426 patients in this study. Their mean age was 29.9 ± 22 years. Total medical costs per member per month decreased by $1,949 (18.6%) after initiation of HFCWO (P = 0.002). Inpatient admission costs decreased by $2,392 (41.7%) (P = 0.001), and pneumonia costs decreased by $514 (18.1%) (P = 0.015). To account for the possibilities of misclassification based on diagnosis and bias due to loss to follow-up, we compared outcomes between those lost to follow-up and those not, and we found similar results.

CONCLUSIONS

Total medical costs, hospitalizations, and pneumonia claims were less after than before initiation of HFCWO in a broad group of patients with neuromuscular disease. Subject to the limitations that administrative data did not capture how HFCWO was used and that HFCWO may be a marker of generally better care, our findings lend support to the routine use of this intervention in the care of patients with neuromuscular diseases.

A Controlled Trial of Inhaled Bronchodilators in Familial Dysautonomia

BACKGROUND

Chronic lung disease is a leading cause of premature death in patients with familial dysautonomia (FD). A significant number of patients have obstructive airway disease, yet it is not known whether this is pharmacologically reversible.

METHODS

We conducted a double-blind, placebo-controlled, randomized clinical trial comparing the beta 2 agonist albuterol with the muscarinic blocker ipratropium bromide in patients homozygous for the IKBKAP founder mutation. Albuterol, ipratropium bromide, and placebo were administered on 3 separate days via nebulizer in the seated position. Airway responsiveness was evaluated using spirometry and impulse oscillometry 30 min post dose. Cardiovascular effects were evaluated by continuous monitoring of blood pressure, RR intervals, cardiac output, and systemic vascular resistance.

RESULTS

A total of 14 patients completed the trial. Neither active agent had significant detrimental effects on heart rate or rhythm or blood pressure. Albuterol and ipratropium were similar in their bronchodilator effectiveness causing significant improvement in forced expiratory volume in 1-s (FEV1, p = 0.002 and p = 0.030). Impulse oscillometry measures were consistent with a reduction in total airway resistance post nebulization (resistance at 5 Hz p < 0.006).

CONCLUSION

Airway obstruction is pharmacologically reversible in a number of patients with FD. In the short term, both albuterol and ipratropium were well tolerated and not associated with major cardiovascular adverse events.

Obstructive Sleep-Disordered Breathing Is More Common than Central in Mild Familial Dysautonomia

STUDY OBJECTIVES

In familial dysautonomia (FD) patients, sleep-disordered breathing (SDB) might contribute to their high risk of sleep-related sudden death. Prevalence of central versus obstructive sleep apneas is controversial but may be therapeutically relevant. We, therefore, assessed sleep structure and SDB in FD-patients with no history of SDB.

METHODS

11 mildly affected FD-patients (28 ± 11 years) without clinically overt SDB and 13 controls (28 ± 10 years) underwent polysomnographic recording during one night. We assessed sleep stages, obstructive and central apneas (≥ 90% air flow reduction) and hypopneas (> 30% decrease in airflow with ≥ 4% oxygen-desaturation), and determined obstructive (oAI) and central (cAI) apnea indices and the hypopnea index (HI) as count of respective apneas/hypopneas divided by sleep time. We obtained the apnea-hypopnea index (AHI4%) from the total of apneas and hypopneas divided by sleep time. We determined differences between FD-patients and controls using the U-test and within-group differences between oAIs, cAIs, and HIs using the Friedman test and Wilcoxon test.

RESULTS

Sleep structure was similar in FD-patients and controls. AHI4% and HI were significantly higher in patients than controls. In patients, HIs were higher than oAIs and oAIs were higher than cAIs. In controls, there was no difference between HIs, oAIs, and cAIs. Only patients had apneas and hypopneas during slow wave sleep.

CONCLUSIONS

In our FD-patients, obstructive apneas were more common than central apneas. These findings may be related to FD-specific pathophysiology. The potential ramifications of SDB in FD-patients suggest the utility of polysomnography to unveil SDB and initiate treatment.

COMMENTARY

A commentary on this article appears in this issue on page 1583.

Management of bronchial secretions with Free Aspire in children with cerebral palsy: impact on clinical outcomes and healthcare resources

Background

Management of secretions in children with cerebral palsy is often problematic due to severe deformation of the rib cage, impaired cough, and patients’inability to collaborate with chest physiotherapy. Assessing the effectiveness of different methods and techniques of secretion clearance is hampered by the lack of direct outcome measures and by limited patient cooperation.

This observational study was planned to evaluate the efficacy of Free Aspire, a device that utilizes a special method to remove secretions from the bronchial tree in hypersecretive patients.

Case presentation

Cerebral palsy patients were selected who had experienced more than 3 episodes of respiratory exacerbations in the latest year despite therapeutic optimization (including bronchial clearance techniques) and who had received at least one antibiotic course or underwent at least one access to the Emergency Room (ER) or admission to hospital in the 6 months prior to the study. Patients with congestive heart failure or contraindications for Free Aspire were excluded. We prospectively enrolled 8 patients (mean age 8.25 ± 6.11 years) who had been using in the past techniques for clearance secretions different from Free Aspire.

The treatment with Free Aspire consisted of at least two 20-min sessions per day. The observational study period was 18 months.

In the 6 months prior to start the treatment (T0), patients had a mean number of 4.0 ± 2.23 visits from the primary care pediatrician (PCP), spent 14 ± 20 days in hospital, and received antibiotics for 35 ± 17 days. After the first 6 months of treatment (T1), they had 1.7 ± 0.73 PCP visits, no days spent in hospital, and 9.75 ± 10.4 days of antibiotic therapy. At 12 months of treatment (T2), PCP visits were 1.7 ± 0.70, days in hospital 1.12 ± 0.3, and days of antibiotics 10.25 ± 10. At 18 months of treatment (T3) no hospitalizations had occurred, PCP visits were 0.25 ± 0.70, and days of antibiotic therapy 4.8 ± 12.62. The technique proved to be safe and well tolerated.

Conclusion

Our findings show that Free Aspire for bronchial secretion clearance in cerebral palsy patients with limited capacity to collaborate is safe and effective in reducing the impact of respiratory exacerbations in terms of number of PCP visits, days spent in hospital, and days of antibiotic therapy; its regular use maintains this effect in time.

Current treatments in familial dysautonomia

INTRODUCTION

Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (ELP-1) (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception result in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss.

AREAS COVERED

This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene-modifying agents.

EXPERT OPINION

Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to the risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression.

High-frequency chest wall oscillation in prolonged mechanical ventilation patients: a randomized controlled trial

BACKGROUND AND AIMS

Patients with prolonged mechanical ventilation (PMV) often retain airway secretions, which may be cleared with the assistance of high-frequency chest wall oscillation (HFCWO). This study aimed to determine the effectiveness, safety and tolerance/comfort of HFCWO after extubation in PMV patients.

METHODS

This parallel-designed, randomized controlled trial enrolled subjects with both intra-tracheal intubation and mechanical ventilator support continuously for at least 21 days between January 2011 and December 2012. Upon extubation, the participants were randomly assigned to either receive HFCWO for 5 days or not. The effectiveness [based on weaning success rates, daily clearance volume of sputum, serial changes in sputum coloration and chest X-ray (CXR) improvement rates], safety (by physiologic parameters) and tolerance/comfort [using the Modified Borg Scale (MBS) and Hamilton Anxiety Scale (HAS)] of HFCWO were investigated.

RESULTS

There were 43 PMV subjects, including 23 in the HFCWO group and 20 in the non-HFCWO group. The weaning success rates were 82.6% (19/23) and 85% (17/20) in the HFCWO and non-HFCWO groups, respectively (P = 1.000). The HFCWO group had persistently greater numbers of daily sputum suctions and higher CXR improvement rates compared with the non-HFCWO group. There was significant sputum coloration lightening in the HFCWO group only. There was no significant difference in the MBS and HAS between the two groups and between pre- and post-HFCWO physiologic parameters.

CONCLUSION

In PMV patients, HFCWO was safe, comfortable and effective in facilitating airway hygiene after removal of endotracheal tubes, but had no positive impact on weaning success.

Assessment of the implementation of a protocol to reduce ventilator-associated pneumonia in intensive care unit trauma patients

Ventilator-associated pneumonia (VAP) is the primary hospital-acquired infection contracted by critically ill patients who receive mechanical ventilation. This retrospective study evaluated the efficacy of a multifaceted VAP prevention protocol in an adult trauma population. Ventilator-associated pneumonia was defined according to the National Healthcare Safety Network (2009) criteria. The number of days to onset of VAP in the postprotocol period was longer than the preprotocol period despite a concomitant increase in the number of mechanical ventilation days.

Intraoperative use of a chest physiotherapy system during whole lung lavage for pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare condition caused by the excessive alveolar accumulation of surfactant proteins. The current standard of care for removing these secretions is through therapeutic whole lung lavage (WLL). We describe two successful cases of bilateral WLL involving the novel use of the Vest™ chest physiotherapy system thereby avoiding the need for extensive changes in patient position in the intraoperative period. In brief, it involves the induction of general anesthesia followed by single-lung ventilation while simultaneously performing large volume lavages on the nonventilated lung. The washout was enhanced using the Vest™ system.

Safety, tolerability, and efficacy of high-frequency chest wall oscillation in pediatric patients with cerebral palsy and neuromuscular diseases: an exploratory randomized controlled trial

Airway secretions and infections are common in cerebral palsy and neuromuscular diseases. Chest physiotherapy is standard therapy but effort is substantial. High-frequency chest wall oscillation is used in cystic fibrosis but tolerability and safety data in cerebral palsy and neuromuscular disease are limited. A prospective, randomized, controlled trial of high-frequency chest wall oscillation and standard chest physiotherapy was performed in participants with neuromuscular disease or cerebral palsy. Outcome measures included respiratory-related hospitalizations, antibiotic therapy, chest radiographs, and polysomnography. Care-givers were questioned regarding therapy adherence. A total of 28 participants enrolled, 23 completed (12 chest physiotherapy, mean study period 5 months). No adverse outcomes were reported. Adherence to prescribed regimen was higher with high-frequency chest wall oscillation (P = .036). Our data suggest safety, tolerability, and better compliance with high-frequency chest wall oscillation. Improvement in airway clearance may help prevent hospitalizations. Larger controlled trials are required to confirm these results.

The molecular basis of familial dysautonomia: overview, new discoveries and implications for directed therapies

Familial dysautonomia (FD) is a sensory and autonomic neuropathy that affects the development and survival of sensory, sympathetic, and some parasympathetic neurons. It is autosomally inherited and occurs almost exclusively among individuals of Ashkenazi Jewish descent. The pathological and clinical manifestations of FD have been extensively studied and therapeutic modalities have, until recently, focused primarily on addressing the symptoms experienced by those with this fatal disorder. The primary FD-causing mutation is an intronic nucleotide substitution that alters the splicing of the IKBKAP-derived transcript. Recent efforts have resulted in the development of new therapeutic modalities that facilitate the increased production of the correctly spliced transcript and mitigate the symptoms of those with FD. Furthermore, the recent demonstration of the reduced presence of monoamine oxidase A in cells and tissues of individuals with FD has provided new insight into the cause of hypertensive crises experienced by these patients.