The Czech Pneumological and Physiological Society and the Czech Society for Paediatric Pulmonology Guidelines for Long-term Home Treatment Using the CoughAssist Machine in Patients with Serious Cough Disorders

Summary

Serious cough disorders occurring especially in neurological diseases such as spinal muscular atrophy, muscular dystrophy and amyotrophic lateral sclerosis are associated with a significant respiratory muscle weakness. Muscular dysfunction in these patients gradually reduces cough efficacy, which increases the risk of respiratory complications in these patients. The most common complications include stagnation of bronchial secretions, increased risk for mucous plugging, development of atelectasis, increased risk of pneumonia and respiratory failure. Therefore, it is important to include mechanical insufflation/exsufflation with the CoughAssist machine in the comprehensive treatment of these patients. This type of non-pharmacological therapy improves cough efficacy or completely replaces cough. CoughAssist machine can be used for treatment of serious cough disorders in paediatric and adult patients. The indications for long-term home treatment using this device are listed in the national guidelines approved by the Czech Pneumological and Phthiseological Society and Czech Society of Paediatric Pneumology. This type of therapy can be indicated in specialized centres. When patients meet the indication criteria partial reimbursement (75%) is possible from health insurance in the Czech Republic since 2017.

Key words:
cough – CoughAssist – peak cough flow – respiratory muscles – respiratory muscle strength – treatment guideline

Serious cough insufficiency

Airway clearance disorders and cough insufficiency may appear due to various reasons. In addition to changes of mucus viscosity in patients with cystic fibrosis and bronchiectasis the major cause of cough insufficiency is associated with respiratory muscle weakness and fatigue in neurological diseases [1,2]. Respiratory muscle weakness and/or their fatigue can negatively influence the inspiratory and expiratory phase of cough. If the bulbar muscle function is also impaired, the compression phase of coughing might be affected as well. For effective cough it is important that the peak flow (Peak Cough Flow; PCF) reaches at least 160 l/min during the expiratory phase of cough. PCF ranges between 360–1,200 litres per minute in healthy adult individuals. If the PCF is lower than 120 l/min, the mucus clearance is reduced to a minimum and therefore sputum plugs might be formed. Atelectasis, a higher risk of pneumonia and respiratory failure may develop in these patients [3–6]. Airway clearance and cough disorders can therefore represent a serious life-threatening risk with other serious health complications in conditions such as spinal muscular atrophy, Duchenne and Becker muscular dystrophy, amyotrophic lateral sclerosis, Charcot Marie Tooth disease, myopathy, cerebral palsy, Huntington's disease, spinal cord injury (cervical and thoracic spine in particular) and conditions associated with impaired innervation of respiratory muscles [1].

Treatment of serious cough insufficiency

Preferably an active treatment approach using chest physiotherapy techniques should be used in patients who are still able to generate efficient PCF. The most frequently used techniques for mobilising sputum from the peripheral airways to the central ones are autogenic drainage, an active cycle of breathing techniques and the use of breathing devices like PARI O-PEP, shaker, RC-cornet, acapella and threshold positive expiratory pressure (PEP). If the treatment needs to be aimed for improving the respiratory muscle strength, breathing devices like threshold inspiratory muscle trainer (IMT), threshold PEP or POWERbreathe could be used. These breathing devices can be prescribed to patients by their consultant – a neurologist, pulmonologist, allergist, paediatrician and/or a specialist in rehabilitation medicine. Some of these devices (threshold IMT, threshold PEP, PARI O-PEP, RC-cornet, PARI PEP S-system, shaker classic and shaker de lux) are partially covered (75%) by health insurance [7].

In patients who are no longer able to generate efficient PCF, non-invasive mechanical insufflation/exsufflation becomes necessary as a treatment approach. Mechanical insufflation supports the inspiratory phase of cough during which lungs are expanded, which is important for an effective expiratory phase of cough. Mechanical exsufflation enables mucus to evacuate from the periphery towards the central airways and therefore enhances its removal. Mechanical insufflation/exsufflation can be used as cough support or it can completely substitute cough not only during acute but also during chronic disease with excessive sputum production. This device can also support or substitute cough, if patient aspirates. This device can also be used for clearing upper airways (blowing the nose), which is another advantage of CoughAssist machine [3–6,8,9].

If these treatment approaches are not applied in time, there is a higher risk of serious respiratory complications (stagnation of bronchial secretion, increased risk of mucous plugging, atelectasis and respiratory failure). This risk of complications can also be reduced by suction during bronchoscopy or in patients with tracheostomy, but these are invasive approaches and should only be used if the non-invasive techniques become unsuccessful in preventing respiratory complications.

The use of mechanical insufflation/exsufflation in the therapy

CoughAssist has been used as a device for treating airway clearance and cough disorders in the Czech Republic since 2009. A new version of the device – CoughAssist E70 is available since 2012. However, due to the lack of specialists in this field this alternative treatment option was not even used much for patients in either hospital or home environment. On the other hand, the non-invasive cough-augmentation therapy with CoughAssist machine to support airway clearance is recommended in the Czech Pneumological and Physeological Society Pulmonary Rehabilitation guideline, which was validated and accepted by this Society in 2014 and by the Czech Society of Rehabilitation and Physical Medicine Czech Medical Association of J. E. Purkyne in 2015 [10]. Recently (autumn 2016), the guidelines for the prescription and long-term home use of the mechanical insufflation/exsufflation with the use of the CoughAssist machine was introduced by the Czech Pneumological and Physeological Society and the Czech Society for Paediatric Pulmonology [11]. And since 1. 2. 2017 it has been validated as a treatment approach for paediatric and adult patients providing that the inclusion criteria are met. The cost is partially included in the health insurance (75%). Patient circuit (mask or mouthpiece or trach adaptor, flexible tubing and bacterial filter) has been partially covered by health insurance since 1. 4. 2017 (75%). Thus, the Czech Republic joined the countries, especially in Western Europe (eg. Germany, Belgium, France, Switzerland, Italy, Spain, and Portugal), in which this care is covered by health insurance. Among the countries of Central and Eastern Europe, this therapy is covered in paediatric and adult patients only in the Czech Republic and Slovenia.

Both the inspiratory and expiratory components of coughing can be adjusted individually when setting the CoughAssist device. The inspiratory phase should be longer then the expiratory so that it could imitate natural cough, which can be performed completely by the device without patient’s participation or as a supplementation of the patient’s coughing effort (active participation) based on the preselected pressure intensity. Apart from the manual and automatic mode, the device also offers a special function called Cough-Trak which synchronises the automatic mode with the patient’s inspiratory effort. CoughAssist E70 also offers an oscillating mode that eases the mobilisation of the phlegm. Oscillation can be used in both the manual and automatic mode as well as during either inspiratory or expiratory component of coughing or in both. In practice, the therapy is applied to a patient through a facial mask or a mouthpiece. In patients who have a tracheostomy, a trach adaptor has to be used [9,12]. So far, positive effects have been confirmed in patients with spinal muscular atrophy [9,13,14], Duchenne muscular dystrophy [15,16], amyotrophic lateral sclerosis [6,17,18], chronic obstructive pulmonary disease [19], spinal cord injury [8,20] and as well as in patients with cerebral palsy [21]. Similarly as in adult patients, the positive effects of the treatment have been seen also in paediatric patients with a neuromuscular disorder [22–24]. Based on the evidence, the treatment can be used in children, who are older than 3 months [25]. Mechanical insufflations/exsufflation is well tolerated in patients with serious cough disorders [19,26–28]. They experience elimination or minimizations of unpleasant symptoms associated with cough difficulties, sputum retention and inefficient phlegm mobilization, which results in the quality of life improvement. Airway clearance and cough disorders can be treated with this device in most patients during outpatient or long-term home therapy.

One of the most common serious complications resulting from the stagnation of bronchial secretion is an infection of the lower respiratory pathways, which represents the most frequent reason for hospital admission [9,16,29]. Bento et al. [12] observed 20 patients with neuromuscular disorders – amyotrophic lateral sclerosis (15 patients), Duchenne muscular dystrophy (2 patients) and other neuromuscular disorders (3 patients) for 4 years to assess the impact of mechanical insufflation/exsufflation on the reduction of hospital admission due to chest infections. Patients were introduced to the use of the CoughAssist machine to keep the study protocol standardised. In the feedback, patients were reporting that the episodes of desaturation due to sputum retention were easily managed with the use of the CoughAssist machine at home, which otherwise would have resulted in the hospital admission. An early indication of the mechanical insufflation/exsufflation during hospital admission reduces the risk of intubation of the patient, makes the weaning quicker and reduces the need of re-intubation [30]. The goals of the treatment are to improve the quality of life and to minimize the symptoms and serious health complication caused by inefficient cough (fatigue, pain, sputum retention, atelectasis and aspiration pneumonia). Furthermore, this type of treatment is cost-effective, reduces hospital admission and reduces mortality due to complications arising from inefficient cough.

Indications

Mechanical insufflation/exsufflation is indicated in stable or hospitalized patients with impaired airway clearance due to ineffective cough. On the initial assessment performed either by the respiratory, paediatric and neurology consultant, the type and frequency of cough is inquired, as well as the number of previous upper or lower airway infections, dysphagia and frequency of aspirations. Lung function tests (vital capacity, forced expiratory volume in 1 second, peak expiratory volume and peak cough flow), maximal inspiratory/expiratory mouth (nose) pressures and resting saturation are evaluated providing that the patient is able to actively perform the manoeuvres according to the standards. A CT scan or X-ray examination can help to rule out possible contraindications for the mechanical insufflation/exsufflation in case there is suspected damage of airways or lung structures (e.g. pneumothorax, bullous emphysema etc.).

The indication for the long-term use of CoughAssist is based on the recommendations coming from the multidisciplinary specialists’ team meeting (depending on the patient’s age, type of disease – respiratory consultant, paediatric consultant, neurology consultant and physiotherapist) in specialized centres (Tab.1, 2). Following the decision, the attending physician indicates the treatment that is individually prescribed by the physiotherapist. Later on, the setting and the application of the treatment is performed by either the patient or family members/carers. Patients are monitored regularly (at least once a year) by their specialist consultant (pulmonologist, paediatric pulmonologist, neurologist) who should always confirm that the criteria for the treatment are still met and checks if any changes in the treatment programme setting are necessary. Extra consultations with the specialist consultant or a physiotherapist might be required to readjust the pressures for insufflation and exsufflation in case of acute worsening of the patients’ state of health, unless the treatment is no longer indicated due to the changed state of health of patients. For children this is always done in the presence of their parent of adult guardian. In case of a patient’s admission to hospital, the use of CoughAssist machine during the hospital stay should be discussed with the physician who has a patient in their care.

Inclusion criteria for the use of CoughAssist machine:

Inefficient cough with sputum retention, reduced peak cough flow, respiratory muscle weakness and/or fatigue in one of the three following situations:

1. In adult patients, who are able to actively perform manoeuvres according to the standards, CoughAssist machine is indicated, when:

• a) vital capacity is less than 50% of predicted value,
• b) peak expiratory flow is less than 2.7 l/s,
• c) peak cough flow is less than 160 l/min,
• d) maximal inspiratory mouth pressure or sniff nasal inspiratory pressure is less than 80% of predicted value,
• e) maximal expiratory mouth pressure is less than 80% od predicted value,
• f) blood saturation is less than 90%,
• g) frequent meal or liquid aspirations,
• h) respiratory muscle fatigue.

Any four criteria from the list above together with inefficient cough represent the indication for the mechanical insufflation/exsufflation treatment in adult patients.

2. In children, who are able to actively perform manoeuvres according to the standards, CoughAssist machine is indicated, when:

• a) vital capacity is less than 60% of predicted value,
• b) peak expiratory flow is less than 70% of predicted value,
• c) maximal inspiratory mouth pressure or sniff nasal inspiratory pressure is less than 80% of predicted value,
• d) maximal expiratory mouth pressure is less than 80% od predicted value,
• e) blood saturation is less than 90%,
• f) frequent meal or liquid aspirations,
• g) respiratory muscle fatigue,
• h) family member/carer able to participate in the treatment.

Any four criteria from the list above together with inefficient cough represent the indication for the mechanical insufflation/exsufflation treatment in paediatric patients.

3. In adult and paediatric patients who are unable to actively participate in the lung function tests and respiratory muscle strength assessment due to the disease severity, impaired health status or young age, the treatment is prescribed based on the clinical signs and symptoms of inefficient cough.

Conclusion

Accessibility and extended use of the non-invasive treatment approaches for the airway clearance and cough disorders represents useful and successful treatment alternative for patients with the respiratory muscle weakness and fatigue. The priority is that all health specialists (neurologist, pulmonologist, and physiotherapist) are aware of this therapeutic approach. An early start of the treatment may help to prevent serious health respiratory complications and therefore it can help to maintain good quality of life in patients with cough insufficiency as long as possible.