Pneumothorax in neuromuscular disease associated with lung volume recruitment and mechanical insufflation-exsufflation

Comparison of Mechanical Insufflation-Exsufflation and Hypertonic Saline and Hyaluronic Acid With Conventional Open Catheter Suctioning in Intubated Patients

BACKGROUND

Open respiratory secretion suctioning with a catheter causes pain and tracheobronchial mucosal injury in intubated patients. The goal of mechanical insufflation-exsufflation (MI-E) is to move secretions proximally and noninvasively by generating a high peak expiratory air flow. Nebulized hypertonic saline with hyaluronic acid (HS-HA) may facilitate suctioning by hydration. We assessed the safety and tolerance of a single session of airway clearance with MI-E and HS-HA in critically ill intubated patients.

METHODS

Adults with a cuffed artificial airway were randomized to (1) open suctioning, (2) open suctioning after HS-HA, (3) MI-E, or (4) MI-E with HS-HA. Adverse events, pain and sedation/agitation scores, and respiratory and hemodynamic variables were collected before, during, and 5-min and 60-min post intervention.

RESULTS

One-hundred twenty subjects were enrolled and completed the study. Median (interquartile range [IQR]) Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22 (16-28); median (IQR) age was 69.0 (57.0-75.7) y, and 90 (75%) were male. Baseline respiratory and hemodynamic variables were comparable. Adverse events occurred in 30 subjects (25%), with no between-group differences. Behavioral pain equivalents and Richmond Agitation-Sedation Scale were higher during suctioning in groups 1 (P < .001) and 2 (P < .001). Independent predictive variables for higher pain and agitation/sedation scores were study groups 1 and 2 and simultaneous analgosedation, respectively. Noradrenaline infusion rates were lower at 60 min in groups 2 and 4. PaO2 /FIO2 had decreased at 5 min after open suctioning in group 1 and increased at 60 min in group 3.

CONCLUSIONS

We observed no difference in adverse events. MI-E avoids pain and agitation.

The complexity of multidisciplinary respiratory care in amyotrophic lateral sclerosis

Motor neurone disease/amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with no known cure, where death is usually secondary to progressive respiratory failure. Assisting people with ALS through their disease journey is complex and supported by clinics that provide comprehensive multidisciplinary care (MDC). This review aims to apply both a respiratory and a complexity lens to the key roles and areas of practice within the MDC model in ALS. Models of noninvasive ventilation care, and considerations in the provision of palliative therapy, respiratory support, and speech and language therapy are discussed. The impact on people living with ALS of both inequitable funding models and the complexity of clinical care decisions are illustrated using case vignettes. Considerations of the impact of emerging antisense and gene modifying therapies on MDC challenges are also highlighted. The review seeks to illustrate how MDC members contribute to collective decision-making in ALS, how the sum of the parts is greater than any individual care component or health professional, and that the MDC per se adds value to the person living with ALS. Through this approach we hope to support clinicians to navigate the space between what are minimum, guideline-driven, standards of care and what excellent, person-centred ALS care that fully embraces complexity could be.

Educational aims

To highlight the complexities surrounding respiratory care in ALS.To alert clinicians to the risk that complexity of ALS care may modify the effectiveness of any specific, evidence-based therapy for ALS.To describe the importance of person-centred care and shared decision-making in optimising care in ALS.

The role of lung volume recruitment therapy in neuromuscular disease: a narrative review

Respiratory muscle weakness results in substantial discomfort, disability, and ultimately death in many neuromuscular diseases. Respiratory system impairment manifests as shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing, and chronic ventilatory failure. Ventilatory support (i.e., non-invasive ventilation) is an established and key treatment for the latter. As survival outcomes improve for people living with many neuromuscular diseases, there is a shift towards more proactive and preventative chronic disease multidisciplinary care models that aim to manage symptoms, improve morbidity, and reduce mortality. Clinical care guidelines typically recommend therapies to improve cough effectiveness and mobilise mucus, with the aim of averting acute respiratory compromise or respiratory tract infections. Moreover, preventing recurrent infective episodes may prevent secondary parenchymal pathology and further lung function decline. Regular use of techniques that augment lung volume has similarly been recommended (volume recruitment). It has been speculated that enhancing lung inflation in people with respiratory muscle weakness when well may improve respiratory system "flexibility", mitigate restrictive chest wall disease, and slow lung volume decline. Unfortunately, clinical care guidelines are based largely on clinical rationale and consensus opinion rather than level A evidence. This narrative review outlines the physiological changes that occur in people with neuromuscular disease and how these changes impact on breathing, cough, and respiratory tract infections. The biological rationale for lung volume recruitment is provided, and the clinical trials that examine the immediate, short-term, and longer-term outcomes of lung volume recruitment in paediatric and adult neuromuscular diseases are presented and the results synthesised.

Cardiovascular autonomic dysfunction induced by mechanical insufflation-exsufflation in Guillain-Barré syndrome

Mechanical insufflation-exsufflation (MI-E) is an effective airway clearance device for impaired cough associated with respiratory muscle weakness caused by neuromuscular disease. Its complications on the respiratory system, such as pneumothorax, are well-recognized, but the association of the autonomic nervous system dysfunction with MI-E has never been reported. We herein describe two cases of Guillain-Barré syndrome with cardiovascular autonomic dysfunction during MI-E: a 22-year-old man who developed transient asystole and an 83-year-old man who presented with prominent fluctuation of blood pressure. These episodes occurred during the use of MI-E with abnormal cardiac autonomic testing, such as heart rate variability in both patients. While Guillain-Barré syndrome itself may cause cardiac autonomic dysfunction, MI-E possibly caused or enhanced the autonomic dysfunction by an alternation of thoracic cavity pressure. The possibility of MI-E-related cardiovascular complications should be recognized, and its appropriate monitoring and management are necessary, particularly when used for Guillain-Barré syndrome patients.

Standardization of Air Stacking as Lung Expansion Therapy for Patients With Restrictive Lung Disease: A Pilot Study

OBJECTIVE

Although air stacking is a widely used lung expansion therapy essential for restrictive lung diseases, important details such as peak insufflation pressure (PIP) and number of squeezes have not been investigated. The purpose of this study was to standardize a method of air stacking to minimize problems with its application by identifying the optimal pressure and number of squeezes performed by professional physicians and investigating the current status of routine air stacking implementation in patients.

METHODS

This prospective cross-sectional test-retest study involved individuals who had neuromuscular disorders and had performed air stacking exercise for longer than 1 year. PIP and number of squeezes were measured to identify the differences between caregivers and physicians. Cases of incorrectly performed air stacking were investigated and categorized. The problems associated with air stacking were evaluated.

RESULTS

A total of 45 participants were included. PIP was 41.4 (SD = 4.2; range = 34.8-50.0) cm H2O, and optimal number of squeezes was 3.1 (SD = 0.5; range = 2-4). When the air stacking methods used by caregivers were evaluated, 19 of 45 caregivers (42.2%) used methods inappropriately. Higher PIP and larger number of squeezes were observed with caregiver implementation. Thirty caregivers (66.7%) experienced finger or wrist pain; this problem was observed especially in female caregivers, who tended to incorrectly perform air stacking.

CONCLUSIONS

This pilot study showed that the optimal pressure of air stacking was 35 to 50 cm H2O. Caregivers often perform air stacking inappropriately, leading to complications without achieving the purpose of air stacking. The introduction of a new method, such as manometry, can be helpful for achieving optimal air stacking.

IMPACT

Optimal pressure of air stacking can be measured with inexpensive, simple, and commercially available digital manometry. This approach enables air stacking to be performed and taught more accurately and efficiently and reduces complications in both patients and caregivers.

The Use of Mechanical Insufflation-Exsufflation in Invasively Ventilated Critically Ill Adults

Mechanical insufflation-exsufflation (MI-E) is traditionally used in the neuromuscular population. There is growing interest of MI-E use in invasively ventilated critically ill adults. We aimed to map current evidence on MI-E use in invasively ventilated critically ill adults. Two authors independently searched electronic databases MEDLINE, Embase, and CINAHL via the Ovid platform; PROSPERO; Cochrane Library; ISI Web of Science; and International Clinical Trials Registry Platform between January 1990-April 2021. Inclusion criteria were (1) adult critically ill invasively ventilated subjects, (2) use of MI-E, (3) study design with original data, and (4) published from 1990 onward. Data were extracted by 2 authors independently using a bespoke extraction form. We used Mixed Methods Appraisal Tool to appraise risk of bias. Theoretical Domains Framework was used to interpret qualitative data. Of 3,090 citations identified, 28 citations were taken forward for data extraction. Main indications for MI-E use during invasive ventilation were presence of secretions and mucus plugging (13/28, 46%). Perceived contraindications related to use of high levels of positive pressure (18/28, 68%). Protocolized MI-E settings with a pressure of ±40 cm H₂O were most commonly used, with detail on timing, flow, and frequency of prescription infrequently reported. Various outcomes were re-intubation rate, wet sputum weight, and pulmonary mechanics. Only 3 studies reported the occurrence of adverse events. From qualitative data, the main barrier to MI-E use in this subject group was lack of knowledge and skills. We concluded that there is little consistency in how MI-E is used and reported, and therefore, recommendations about best practices are not possible.

Setting Mechanical Insufflation-Exsufflation (MI-E) Pressures for Amyotrophic Lateral Sclerosis (ALS) Patients to Improve Atelectasis and Reduce Risk of Pneumothorax: A Case Report

Mechanical insufflation-exsufflation (MI-E) has been used to supplement the ability to cough and expel pulmonary secretions in patients with neuromuscular disease who have a reduced ability to cough. The manufacturer's guidelines for MI-E recommend a setting of inspiratory pressure of +40 cmH₂O and expiratory pressure of -40 cmH₂O. However, patients with small stature and restricted ventilatory impairment are prone to pneumothorax, so the manufacturer's recommendations are not used as is, and should be adjusted for the physical and pulmonary characteristics of each patient. Here, we report a case in which MI-E was used for an amyotrophic lateral sclerosis (ALS) patient with short height, low BMI, and restricted lung capacity at inspiratory and expiratory pressures lower than the manufacturer's recommendations. In adjusting MI-E pressure, physical observations such as chest auscultation, visual chest dilation, and observation of secretion movement toward the tracheal tube were performed to avoid unnecessary pressure. As a result, the pressure level set was lower than the manufacturer's recommendation (25 cmH₂O) but sufficient to improve atelectasis and no pneumothorax occurred. The method we practiced in this study is feasible in any clinical setting. We also believe that MI-E, when performed in conjunction with treatment response observation, can be expected to improve at lower pressures than generally recommended, thereby reducing the risk of lung injury and providing safer treatment.

Changes in ventilation distribution in children with neuromuscular disease using the insufflator/exsufflator technique: an observational study

Patients with neuromuscular disease often suffer from weak and ineffective cough resulting in mucus retention and increased risk for chest infections. Different airway clearance techniques have been proposed, one of them being the insufflator/exsufflator technique. So far, the immediate physiological effects of the insufflator/exsufflator technique on ventilation distribution and lung volumes are not known. We aimed to describe the immediate effects of the insufflator/exsufflator technique on different lung volumes, forced flows and ventilation distribution. Eight subjects (age 5.8–15.2 years) performed lung function tests including spirometry, multiple breath washout and electrical impedance tomography before and after a regular a chest physiotherapy session with an insufflator/exsufflator device. Forced lung volumes and flows as well as parameters of ventilation distribution derived from multiple breath washout and electrical impedance tomography were compared to assess the short-term effect of the therapy. In this small group of stable paediatric subjects with neuromuscular disease we could not demonstrate any short-term effects of insufflation/exsufflation manoeuvres on lung volumes, expiratory flows and ventilation distribution. With the currently used protocol of the insufflation/exsufflation manoeuvre, we cannot demonstrate any immediate changes in lung function.

Analysis of Pneumothorax in Noninvasive Ventilator Users With Duchenne Muscular Dystrophy

BACKGROUND

With the advancement of cardiorespiratory interventions, the survival rate among patients with Duchenne muscular dystrophy (DMD) has increased. Subsequently, pneumothorax has become a significant problem in patients with prolonged ventilatory support.

RESEARCH QUESTION

What are the frequency, recurrence rate, risk factors, and prognosis of pneumothorax in patients with DMD requiring noninvasive ventilation (NIV)? Also, are there known risk factors of pneumothorax on chest CT scans?

STUDY DESIGN AND METHODS

This retrospective longitudinal cohort study included 176 patients treated between 2006 and 2019. We collected information regarding location, severity, treatment methods, recurrence frequency, abnormal findings on CT scanning, and date of death. We compared the pneumothorax and nonpneumothorax groups. We calculated the estimated survival probabilities from the age at NIV application according to pneumothorax occurrence.

RESULTS

Sixteen of the 176 patients (9.0%) experienced pneumothorax (median age at diagnosis, 24.6 years; range, 20.7-33.7 years). Among the 16 patients, 15 demonstrated pneumothorax after NIV application (median time between diagnosis and initial NIV application, 5.6 years; range, 3 days-9.6 years). Sixteen patients experienced 31 episodes of pneumothoraces (range, one-five episodes); among them, seven episodes (22.6%) were asymptomatic. Known risk factors not clearly visible by radiography scans were found in chest CT scan in 11 patients (68.8%). Seven of 16 patients (43.8%) eventually sustained severe lung damage with pulmonary fibrosis. No significant between-group differences were found in body weight, BMI, and age at NIV application; however, the pneumothorax group showed a significantly higher mortality rate after NIV application.

INTERPRETATION

On pneumothorax occurrence in patients with DMD, recurrences and severe lung damage are common; moreover, these patients show higher mortality rates than patients without pneumothorax. Chest CT scans should be performed to identify risk factors, and treatment should be initiated accordingly. In addition, physicians should consider chest CT scanning in the case of suspected pneumothorax, even if no radiographic abnormality is found.

Optimizing expiratory flows during mechanical cough in a pediatric neuromuscular lung model

Mechanical insufflation-exsufflation (MI-E) is recommended for subjects of all ages with neuromuscular disorders (NMDs) and weak cough. There is a lack of knowledge on the optimal treatment settings for young children. This study aims to determine the MI-E settings providing high expiratory airflow while using safe inspiratory volumes, and to identify possible limits where the benefit of incrementing the MI-E settings to achieve a higher expiratory airflow, decreased. Using an MI-E device and a lung model imitating a 1-year-old child with NMD, we explored the impact of 120 combinations of MI-E pressure and time settings on maximal expiratory airflow and inspiratory volume. High expiratory airflows were achieved with several pressure and time combinations where the exsufflation pressure, followed by insufflation pressure and time, had the greatest impact. The benefit of incrementing the settings to increase the expiratory airflow leveled off for the insufflation pressure and time, but not for the exsufflation pressure. Given exsufflation pressure of -40 or -50 cmH₂ O and insufflation time longer than 1 second, a plateau in the expiratory airflow curve was present at insufflation pressures from 25 cmH₂ O, whereas a plateau in the inspired volume curve occurred at insufflation pressures from 35 cmH₂ O. The present neuromuscular pediatric lung model study showed that expiratory pressure impacts expiratory airflow more than inspiratory pressure and time. An inspiratory and expiratory pressure set between 20 to 30 and -40 cmH₂ O, respectively, and an inspiratory time longer than 1 second may be considered as a basis when titrating MI-E settings in young children with NMD. The findings must be confirmed in clinical trials.