EFA and other airway clearance techniques in a myasthenic crisis| Rassegna di Patologia dell'Apparato Respiratorio

Abstract

A patient affected by myasthenia gravis and bronchiectasis,complicated by a myasthenic crisis, undergoes airway clearance therapy to improve an ab ingests pneumonia and manage secretions clearance; the patient in respiratory distress was treated with non-invasive ventilation (NIV) throughout the day, necessitated by deteriorating spirometric values and peripheral oxygen saturation levels.
A comprehensive multidisciplinary evaluation revealed ineffective cough and dysphagia, prompting the initiation of a combined therapeutic approach of FREE aspire device, mechanical In-Exsufflator (MI-E) and Continuous positive airway pressure (CPAP). The outcomes measured included chest computed tomography (CT) scan, Forced expiratory volume in one second (FEV₁), Forced vital capacity (FVC) and Peak cough expiratory flow (PCEF) and patient-reported satisfaction with visual analogue scale (VAS).

Introduction

Myasthenia gravis is an autoimmune disorder characterized by the impairment of neuromuscular joints, resulting in fluctuating weakness of voluntary muscles and fatigue.

Approximately 10% of patients may develop potentially severe complications due to significant respiratory muscles involvement, resulting in a myasthenic crisis (MC). This condition requires non-invasive and/or mechanic ventilation, enteral feeding, and occasionally intensive care unit admission.

MC arises from the weakening of respiratory muscles, in which causes a reduction in tidal volume and upper respiratory tract muscle weakness that causes airway obstruction.

The weakness of bulbar and oropharyngeal muscles can cause collapse and obstruction of the upper airway and inability to control secretions. This combination of factors often causes suction and hypoxic respiratory failure.

The molecular mechanisms underlying MC remain unclear ¹.

The causes of myasthenic crisis and the primary therapeutic objectives are summarized in Tables I and II, respectively. During a myasthenic crisis, patients affected by myasthenia gravis may need intubation or NIV ventilation to manage acute respiratory failure. Airway clearance techniques are often necessary, as myasthenic crisis can be exacerbated by aspiration pneumonia, upper respiratory tract infections or pneumonia.

In addition to the decline of pulmonary function, patients with myasthenia gravis may also experience a reduction in Peak Cough Expiratory Flow (PCEF).

This case report aims to present an airway clearance treatment strategy that incorporates use of Expiratory Flow Accelerator (EFA) technology, Mechanical In-Exsufflator (MI-E), combined with the use of Continuous Positive Airway Pressure (CPAP). This approach is intended to detect lung atelectasis in a patient with myasthenia gravis complicated by bronchiectasis and ineffective cough during a myasthenic crisis exacerbated by aspiration pneumonia, treated with NIV h24.

Case report

A 42 year-old woman affected by myasthenia gravis and polymyositis arrives at Centro Clinico NeMo Napoli on January 2023 during a myasthenic crisis.

The diagnosis of myasthenia gravis was established in September 2014 at the Caserta Hospital, Italy, where the patient was admitted due to severe asthenia, accompanied by dysphagia and anemia. During her hospitalization anti-acetylcholine receptor antibodies and repetitive stimulation tested positive.

From 2017 to 2019, she was treated with immunoglobulin therapy at the Neuromed Institute in Pozzilli, which provided partial benefit.

In 2019, she was additionally diagnosed with asthma and began specific therapy (budesonide/formoterol fumarate dihydrate -160/4.5 mg - one inhalation twice a day), after which she no longer required oxygen therapy.

Her condition was also complicated by bronchiectasis, Hashimoto’s thyroiditis and colostomy due to rectovaginal fistula.

In November 2022, she developed a respiratory tract infection, which was not treated. On 10^th December 2022, she presented an exacerbation of both myasthenia and respiratory failure, necessitating NIV treatment.

At the time of her admission, the patient was able to eat soft foods, relied on NIV 24 hours a day, and had notable exercise intolerance with desaturation even during minimal physical activity, such as walking. She required assistance with all activities of daily living (ADL).

Evaluation

The patient presented signs of respiratory distress and ventilatory asynchrony; she was alert and well oriented to both time and place. Immediate intervention included immunoglobulin therapy and instrumental examinations: chest X-ray, Arterial blood gases (ABG) analysis and blood count (Tab. III). The patient was taken over by the rehabilitation team and underwent a multidisciplinary assessment.

From the first day of the hospitalization, a respiratory therapist conducted an evaluation, which measured peripheral arterial oxygen saturation (SpO₂) via pulse oximetry and spirometry testing.

The respiratory therapist also checked the chest X-ray and optimized the ventilatory parameters based on the ABG results.

Auscultation revealed wheezing at the end of each exhalation. Bronchoaspirate showed positive for Pseudomonas Aeruginosa, while mucus cultures identified presence of Serratia Marcescens and Enterobacter Cloacae Complex. The patient was treated with Meropenem and Co-trimoxazole.

Intervention

Chest Physical Therapy (CPT) was initiated a few days after the patient’s hospitalization.

The patient was adapted to cough assist device (Kinex – Medical Product Research, Italy) with the following settings: Inspiratory Pressure (PI): +35 cmH₂O; Expiratory Pressure (PE): -35 cmH₂O; Inspiratory Time (IT): 2.2 s; Expiratory Time (ET): 2.2 s; Pause: 1.0.

Clinically, she showed good compensation and did not show any sign of discomfort following the treatment.

The CPT regimen consisted in 5 cycles 5 times twice a day. In the morning, the therapy session was managed by a respiratory physiotherapist, while in the evening by a caregiver trained in the use of the device.

During the hospitalization, inhalation therapy with Budesonide/Formoterol was also optimized to 2 inhalations twice a day.

Due to patient reported persistent cough and presence of sputum, the treatment was optimized as follows:

1. The patient started to use the new technology of Expiratory Flow Accelerator (EFA) with the device Kinex (Medical Product Research, Italy); a device utilizing Vaküm technology to accelerate expiratory flow through the Venturi effect via a special connector. The secretions moves along the layer of liquid lining the bronchial epithelium until they reach the glottis from where they are swallowed ²; it was useful in patient with respiratory distress as it requires no respiratory effort for secretions clearance.
2. The treatment was performed at level 5 for 30 minutes once a day, with a mouthpiece.
3. Mechanical In-Exsufflator (Kinex - Medical Product Research, Italy) was used after the treatment with EFA, as follows: 5 cycles 5 times twice a day, in sitting position.
4. CPAP (Kinex - Medical Product Research, Italy): it was performed with pressure at 7 cmH₂O for 30 minutes, in sitting position, once a day after the treatment with EFA+MI-E.

Additionally, an airway clearance session with cough assist was performed by the caregiver in the evening.

This treatment was executed for the entire duration of the hospitalization.

Furthermore, the patient initially started passive mobilization and later, active-assisted mobilization in bed, at the beginning with ventilatory support. Gradually, she started walking training with aids (walker) without showing any desaturation (SpO₂ > 90% while walking).

Measurements and outcomes

At the beginning and at the end of the hospitalization, the patient’s pulmonary function was assessed using forced spirometry (as shown in Figs. 1 and 2). It indicated significant improvements: Forced Expiratory Volume in 1 Second (FEV₁) increased from 0.60 L at baseline (T0) to 0.84 1 L; and Forced Vital Capacity (FVC) improved from 0.63 L at baseline (T0) to 1.33 L. The patient also reported a decrease in resting dyspnoea with a Borg scale of 1 at the end of the hospitalization compared to Borg scale 8 at T0.

The patient started during the hospitalization, the weaning from NIV (Astral 150 – Resmed, Italy) by using it only at night and during the afternoon; NIV was set as follows: Mode: Spontaneous Timed (S/T); Inspiratory Positive Airway Pressure (IPAP): 18 cmH₂O; Positive End-Expiratory Pressure (PEEP): 7 cmH₂O; Respiratory rate (RR):16 apm; Target Volume: 500 ml; IPAP max: 21 cmH₂O; Inspiratory trigger: high; Expiratory trigger: 40%; Inspiratory Time minimum (IT min): 0.60 s; Inspiratory Time maximum (IT max): 1.70 s.

A follow-up arterial blood gas (ABG) indicated a decrease in respiratory alkalosis (pH 7.36, PCO₂: 36 mmHg; PO₂: 82 mmHg, HCO₃^-: 25.6 mmol/L.

The level of patient satisfaction with expectoration was assessed 10 on the Visual Analogue Scale (VAS). The patient showed a recovery in ADLs, including autonomy and walking. A follow-up chest CT scan showed a clinical picture almost compatible with persistency of coerced and consolidated aspect of middle lobe, but with a better cleansing of bronchiectasis (Fig. 3)

The results are shown below in the Table IV.

Discussion

The treatment of neuromuscular patients in the acute phase is not well documented in the literature. There are no guidelines that promote or discourage the use of a specific airway clearance technique over others, nor are sufficient clinical trials that indicate how to treat respiratory exacerbation of patients affected by myasthenic crisis.

Considering the progression of myasthenia gravis and the severity of myasthenic crisis, CPT appears to be crucial in the treatment of secretions and preventing acute respiratory insufficiency (IRA).

NIV has a primary role during the myasthenic crisis, since it prevents endotracheal intubation ³.

However, the exclusive use of NIV may be ineffective for reducing dyspnea, discomfort related to cough, severe desaturations, and the clearance of bronchiectasis. A combination of MI-E, Free Aspire, and CPAP have been used since the first day of the acute event without showing side effects.

EFA is a recent treatment in the management of neurological/neuromuscular diseases characterized by dysphagia and ineffective cough. Riboldazzi et al. ³, demonstrated that the use of EFA in patients with Parkinson’s disease decreases discomfort caused by cough and feeling of bronchial congestion, resulting in an improvement in quality of life.

The use of Free Aspire takes advantage of the acceleration of expiratory flow rate: the flow produced along the bronchial tree allows the drainage of secretions in the airway up until the trachea. Once the upper airway has been reached, secretions are expectorated or, if the patient is not able to do so, they easily slide into the oesophagus and clear the respiratory tract.

The use of MI-E is widely supported by case reports and trials suggesting an improvement in PCEF to promote the effective removal of secretions. MI-E also appeared to be tolerated by patients, similar to other cough assistance techniques.

In Chen et al. ⁴, the combined use of MI-E and NIV was effective in preventing patients’ intubation with acute respiratory failure (ARF) caused by pneumonia. This non-invasive approach has proved to be useful in reducing the need for frequent suctioning (nasal or oronasal), intubation and tracheostomy.

The additional use of MI-E helps solving the excess of secretions and reduces the risk of NIV failure in the treatment of ARF in patients affected by Neuromuscular Disease (NMD). Therefore, trials suggest that the combination of NIV and MI-E may be implemented as first-line treatment for ARF in children with NMD ⁴.

This case report focuses its attention on a more “invasive” physiotherapeutic approach which may definitely reduce the discomfort caused by exacerbation, which often leads to premature tracheostomy. While this approach is not intended as an alternative to tracheostomy, it is a complement to the use of ventilatory treatment, which is known to be very effective in myasthenic crisis. The treatment suggested in this case report has allowed for the “safe” management of the patient in absence of complications such as severe desaturations, discomfort from the clearance techniques used, tolerance of the treatment itself and aggravation of dyspnea.

Future clinical trials should focus their attention on the treatment of neuromuscular patients in the acute phase and consider the short and long-term effects of a combined approach on pulmonary exacerbation.

History

Ricevuto/Received: 06/05/2024

Accettato/Accepted: 03/09/2024

Figure e tabelle

Figure 1.Pre-intervention spirometry.

Figure 2.Post-intervention spirometry.

Figure 3.Chest CT scans pre (A) and post (B) physiotherapy intervention.

Riferimenti bibliografici

1. Claytor B, Sung-Min C, Yuebing L. Myasthenic crisis. Muscle Nerve. 2023; 68:8-19. DOI
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3. Riboldazzi G, Spinazza G, Beccarelli L. Effectiveness of expiratory flow acceleration in patients with Parkinson’s disease and swallowing deficiency: a preliminary study. Clin Neurol Neurosurg. 2020; 199:106249. DOI
4. Chen TH, Liang WC, Yong YJ. Combined noninvasive ventilation and mechanical insufflator-exsufflator for acute respiratory failure in patients with neuromuscular disease: effectiveness and outcome predictors. Ther Adv Respir Dis. 2019; 13:1753466619875928. DOI