Clinical Implications of Routine Monitoring of Pulmonary Function and Ventilation in Patients with Duchenne Muscular Dystrophy

Purpose@#To investigate the effect of regular monitoring of pulmonary function and ventilatory status on the initiation of non-invasive ventilation (NIV) between patients who were routinely monitored before receiving NIV and those who were not. @*Materials and Methods@#This retrospective cohort study included subjects with Duchenne muscular dystrophy (DMD) who first received NIV between 2010 and 2019. The subjects were assigned to either the regular-follow-up (REG) group or the non-REG group, according to their follow-up status, before initiating NIV. We compared the number of emergent cases, the results of nocturnal ventilatory monitoring, and the pulmonary function of each group at initial ventilatory support. @*Results@#In total, 73 subjects were enrolled in the REG group and 47 subjects in the non-REG group. There were significantly more emergency cases due to respiratory insufficiency in the non-REG group (12/47, 25.5%) than in the REG group (3/73, 4.1%). At the time of initial ventilatory support, hypoventilatory symptoms were more common and relatively severe in the non-REG group (37/47, 78.7%) than in the REG group (18/73, 24.7%). The average age at initial ventilatory support of the non-REG group was 2.15 years older than that of the subjects in the REG group. Moreover, subjects who were not regularly monitored exhibited greater deterioration in pulmonary function compared to those who were regularly followed up. @*Conclusion@#Regular evaluation of pulmonary function and ventilatory status before the onset of ventilatory insufficiency is crucial to reduce the risk of patients with DMD requiring emergency care due to ventilatory insufficiency.

Clinical Course of Amyotrophic Lateral Sclerosis according to Initial Symptoms: An Analysis of 500 Cases

Purpose@#One obstacle in early diagnosis of amyotrophic lateral sclerosis (ALS) is its vague initial presentation, which is generally classified into limb- and bulbar-dominant types and may be mistaken for other musculoskeletal conditions. We analyzed clinical data from patients in relation to their initial presentation and prognosis from symptom onset to diagnosis. @*Materials and Methods@#We retrospectively analyzed the medical records of patients with ALS who were admitted for pulmonary rehabilitation between January 2007 and December 2019. We collected data on time of onset, initial presenting symptoms, unnecessary operations due to misdiagnosis, and the time between symptom onset and final diagnosis of ALS. @*Results@#Among 500 patients, unnecessary operations were performed in 43 patients. The median durations between symptom onset and ALS diagnosis for patients with and without operations were 11 and 9 months, respectively (p=0.008). 67.0%, 28.8%, and 4.2% of the patients presented with limb-, bulbar-, and respiratory-dominant symptoms, respectively, as initial presentations. The median ages at symptom onset were significantly different for limb-, bulbar-, and respiratory-dominant onset (57.5, 60.6, and 66.7 years, respectively; p<0.001). Compared to the other two types, patients with the respiratory-dominant onset were all male and showed higher rate of emergent endotracheal intubation before ALS diagnosis. @*Conclusion@#Inappropriate operations significantly delayed the diagnosis of ALS. Respiratory difficulty can account for a significant proportion among initial presentations in ALS. Compared to limb- and bulbar-dominant types, respiratory-dominant onset appears to show male predominance, older age at symptom onset, and poor respiratory prognosis.

Precise Pulmonary Function Evaluation and Management of a Patient With Freeman-Sheldon Syndrome Associated With Recurrent Pneumonia and Chronic Respiratory Insufficiency

Freeman-Sheldon syndrome (FSS) is a rare distal arthrogryposis syndrome. There are few reports on the respiratory insufficiency of FSS. Additionally, there is no detailed information on pulmonary functional evaluation. A 17-year-old male patient with FSS developed respiratory failure, leading him to be admitted to hospital several times for evaluation and treatment. Of those times he was admitted, two were due to pneumonia. His pulmonary functions were indicative of a restrictive lung disease potentially caused by severe scoliosis. After a non-invasive ventilatorwas applied correctly to the patient, pulmonary hypertension was normalized. His pulmonary function has been maintained for 13 years. Since receiving proper respiratory care, which includes assisted coughing methods, the patient has not developed pneumonia. It is important to properly evaluate the pulmonary function of patients who have FSS and scoliosis to eliminate the risk of long-term respiratory complications.

Improvement of Peak Cough Flow After the Application of a Mechanical In-exsufflator in Patients With Neuromuscular Disease and Pneumonia: A Pilot Study

OBJECTIVE: To investigate and demonstrate persistent increase of peak cough flow after mechanical in-exsufflator application, in patients with neuromuscular diseases and pneumonia. METHODS: A mechanical in-exsufflator was applied with patients in an upright or semi-upright sitting position (pressure setting, +40 and −40 cmH2O; in-exsufflation times, 2–3 and 1–2 seconds, respectively). Patients underwent five cycles, with 20–30 second intervals to prevent hyperventilation. Peak cough flow without and with assistive maneuvers, was evaluated before, and 15 and 45 minutes after mechanical in-exsufflator application. RESULTS: Peak cough flow was 92.6 L/min at baseline, and 100.4 and 100.7 L/min at 15 and 45 minutes after mechanical in-exsufflator application, respectively. Assisted peak cough flow at baseline, 15 minutes, and 45 minutes after mechanical in-exsufflator application was 170.7, 179.3, and 184.1 L/min, respectively. While peak cough flow and assisted peak cough flow increased significantly at 15 minutes after mechanical in-exsufflator application compared with baseline (p=0.030 and p=0.016), no statistical difference was observed between 15 and 45 minutes. CONCLUSION: Increased peak cough flow after mechanical in-exsufflator application persists for at least 45 minutes.

In Reply: Successful Extubation After Weaning Failure by Non-invasive Ventilation in Patients With Neurmuscular Disease – Do We Appreciate the Bigger Picture?

No abstract available.

Multiplex Ligation-Dependent Probe Amplification in X-linked Recessive Muscular Dystrophy in Korean Subjects

PURPOSE: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are similar genetic disorders whose patterns of mutation and disease phenotypes might be expected to show differences among different countries. We analyzed multiplex ligation-dependent probe amplification (MLPA) data in a large number of Korean patients with DMD/BMD. MATERIALS AND METHODS: We obtained 130 positive MLPA results (86 DMD, 27 BMD, and 17 female carriers) from 272 candidates (237 clinically suspected patients and 35 possible female carriers) who took part in this study. We analyzed the mutation patterns among 113 patients diagnosed by MLPA and calculated deletion/duplication percentages from a total of 128 patients, including 15 patients who were diagnosed using methods other than MLPA. We also analyzed hot spot locations among the 130 MLPA-positive results. RESULTS: Most mutations were detected in a central hot spot region between exons 44 and 55 (80 samples, 60.6%). Unlike previous reports, a second frequently observed hot spot near the 5'-end was not distinctive. MLPA detected deletions in specific exons in 92 patients with DMD/BMD (71.8%) and duplications in 21 patients (16.4%). CONCLUSION: Our MLPA study of a large number of Korean patients with DMD/BMD identified the most frequent mutation hot spot, as well as a unique hot spot pattern. DMD gene mutation patterns do not appear to show significant ethnic differences.

Correlation of Serum Creatine Kinase Level With Pulmonary Function in Duchenne Muscular Dystrophy

OBJECTIVE: To investigate the relationship between serum creatine kinase (CK) level and pulmonary function in Duchenne muscular dystrophy (DMD). METHODS: A total of 202 patients with DMD admitted to the Department of Rehabilitation Medicine, Gangnam Severance Hospital were enrolled from January 1, 1999 to March 31, 2015. Seventeen patients were excluded. Data collected from the 185 patients included age, height, weight, body mass index, pulmonary function tests including forced vital capacity (FVC), peak cough flow, maximal expiratory pressure (MEP), and maximal inspiratory pressure (MIP), and laboratory measurements (serum level of CK, CK-MB, troponin-T, and B-type natriuretic peptide). FVC, MEP, and MIP were expressed as percentages of predicted normal values. RESULTS: Serum CK activities were elevated above normal levels, even in the oldest DMD group. Serum CK level was strongly correlated with pulmonary functions of sitting FVC (p<0.001), supine FVC (p<0.001), MIP (p=0.004), and MEP (p<0.001). CONCLUSION: Serum CK level is a reliable screening test even in patients with advanced DMD, and is a strong predictor of pulmonary functions.

Motor Neuron Disease Presenting With Acute Respiratory Failure: A Case Study

Motor neuron diseases (MNDs) refer to a heterogeneous group of progressive neurologic disorders caused by degeneration of motor neurons. The diseases affect either the upper motor neurons, lower motor neurons, or both, and are characterized by weakness, atrophy, fasciculation, spasticity, and respiratory failure. We report a case of a 61-year-old male patient with no past history of cardiovascular or pulmonary disease, who presented with only dyspnea, and no indication of any other symptom such as muscle weakness, atrophy, or bulbar dysfunction. Neuromuscular conduction study, including a study of the phrenic nerve, confirmed the diagnosis of MND. The patient greatly improved giving respiratory assistance at night, using a noninvasive ventilator. This case indicates that MNDs should be considered as differential diagnoses for patients showing acute respiratory failure of unknown causes. This report will aid in the prompt diagnosis and treatment of MNDs.

Long-Term Outcome of Amyotrophic Lateral Sclerosis in Korean Subjects

OBJECTIVE: To report the latest long-term outcome of amyotrophic lateral sclerosis (ALS) and to analyze the predictors of prognosis. METHODS: Subjects who were diagnosed with ALS between January 2005 and December 2009 at a single institute were followed up until death or up to December 2014. Data regarding age, sex, date of onset, date of diagnosis, presence of bulbar symptoms on onset, date of initiation of non-invasive ventilation (NIV), and the date of tracheostomy were collected. Survival was assessed using Kaplan-Meier curves and multivariate analyses of the risk of death were performed using the Cox proportional hazards model. RESULTS: Among 212 suspicious subjects, definite ALS was diagnosed in 182 subjects. The survival rate at 3 and 5 years from onset was 61.5% and 40.1%, respectively, and the survival rate at 3 and 5 years post-diagnosis was 49.5% and 24.2%, respectively. Further, 134 patients (134/182, 73.6%) were initiated on NIV, and among them, 90 patients (90/182, 49.5%) underwent tracheostomy. Male gender and onset age of ≥65 years were independent predictors of adverse survival. CONCLUSION: The analysis of long term survival in ALS showed excellent outcomes considering the overall poor prognosis of this disease.

Successful Extubation After Weaning Failure by Noninvasive Ventilation in Patients With Neuromuscular Disease: Case Series

OBJECTIVE: To report successful cases of extubation from invasive mechanical ventilation at our institution using pulmonary rehabilitation consisting of noninvasive ventilation (NIV) in neuromuscular patients with experience of reintubation. METHODS: Patients who experienced extubation failure via the conventional weaning strategy but afterwards had extubation success via NIV were studied retrospectively. Continuous end-tidal CO₂ (ETCO₂) and pulse oxyhemoglobin saturation (SpO₂) monitoring were performed. Extubation success was defined as a state not requiring invasive mechanical ventilation via endotracheal tube or tracheotomy during a period of at least 5 days. RESULTS: A total of 18 patients with ventilatory failure who initially experienced extubation failure were finally placed under part-time NIV after extubation. No patient had any serious or long-term adverse effect from NIV, and all patients left the hospital alive. CONCLUSION: NIV may promote successful weaning in neuromuscular patients with experience of reintubation.

Respiratory Muscle Strength in Patients With Chronic Obstructive Pulmonary Disease

OBJECTIVE: To compare the respiratory muscle strength between patients with stable and acutely exacerbated (AE) chronic obstructive pulmonary disease (COPD) at various stages. METHODS: A retrospective medical record review was conducted on patients with COPD from March 2014 to May 2016. Patients were subdivided into COPD stages 1–4 according to the Global Initiative for Chronic Obstructive Lung Disease guidelines: mild, moderate, severe, and very severe. A rehabilitation physician reviewed their medical records and initial assessment, including spirometry, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), COPD Assessment Test, and modified Medical Research Council scale. We then compared the initial parameters in patients with a stable condition and those at AE status. RESULTS: The AE group (n=94) had significantly lower MIP (AE, 55.93±20.57; stable, 67.88±24.96; p=0.006) and MIP% (AE, 82.82±27.92; stable, 96.64±30.46; p=0.015) than the stable patient group (n=36). MIP, but not MEP, was proportional to disease severity in patients with AE and stable COPD. CONCLUSION: The strength of the inspiratory muscles may better reflect severity of disease when compared to that of expiratory muscles.

Management of Ventilatory Insufficiency in Neuromuscular Patients Using Mechanical Ventilator Supported by the Korean Government

Since 2001, financial support has been provided for all patients with neuromuscular disease (NMD) who require ventilatory support due to the paralysis of respiratory muscles in Korea. The purpose of this study was to identify ventilator usage status and appropriateness in these patients. We included 992 subjects with rare and incurable NMD registered for ventilator rental fee support. From 21 February 2011 to 17 January 2013, ventilator usage information, regular follow-up observation, and symptoms of chronic hypoventilation were surveyed by phone. Home visits were conducted for patients judged by an expert medical team to require medical examination. Abnormal ventilatory status was assessed by respiratory evaluation. Chronic respiratory insufficiency symptoms were reported by 169 of 992 subjects (17%), while 565 subjects (57%) did not receive regular respiratory evaluation. Ventilatory status was abnormal in 102 of 343 home-visit subjects (29.7%). Although 556 subjects (56%) reported 24-hour ventilator use, only 458 (46%) had an oxygen saturation monitoring device, and 305 (31%) performed an airstacking exercise. A management system that integrates ventilator usage monitoring, counselling and advice, and home visits for patients who receive ventilator support could improve the efficiency of the ventilator support project.

Nutritional Status and Body Composition in Korean Myopathy Patients

In myopathy patients, fat mass increases as the disease progresses, while lean body mass decreases. The present study aimed to investigate the overall nutritional status of Korean myopathy patients through surveys of diet and dietary habits, bioelectrical impedance analysis (BIA), and biochemistry tests, as well as the examination of related factors, for the purpose of using such findings as a basis for improving the nutritional status in myopathy patients. The energy intake of all participants was found to be insufficient at only 44.5% of Dietary Reference Intakes for Koreans 2010 (KDRIs 2010), whereas protein intake was sufficient at 89.8% of KDRIs 2010. Dietary fiber intake was found to be 58.4% of sufficient dietary fiber intake for adults according to KDRIs 2010. Calcium intake was found to be 55.0% and magnesium was 14.9% of the recommended calcium and magnesium intake for adults according to KDRIs 2010. With respect to quality of life (QOL), overall increase in QOL domain score showed significant positive correlations with vegetable fat intake (p < 0.05), vegetable protein intake (p< 0.05), and dietary fiber intake (p < 0.05). With respect to BIA, the mean phage angle of all participants was found to be 2.49 +/- 0.93degrees, which was below the cutoff value. As a study that examined nutrient analysis and dietary habits of myopathy patients in Korea, the present study is meaningful in providing the basic data for future studies that aim to present dietary guidelines for patients suffering from myopathy.

A Comparison of Cough Assistance Techniques in Patients with Respiratory Muscle Weakness

PURPOSE: To assess the ability of a mechanical in-exsufflator (MI-E), either alone or in combination with manual thrust, to augment cough in patients with neuromuscular disease (NMD) and respiratory muscle dysfunction. MATERIALS AND METHODS: For this randomized crossover single-center controlled trial, patients with noninvasive ventilator-dependent NMD were recruited. The primary outcome was peak cough flow (PCF), which was measured in each patient after a cough that was unassisted, manually assisted following a maximum insufflation capacity (MIC) maneuver, assisted by MI-E, or assisted by manual thrust plus MI-E. The cough augmentation techniques were provided in random order. PCF was measured using a new device, the Cough Aid. RESULTS: All 40 enrolled participants (37 males, three females; average age, 20.9±7.2 years) completed the study. The mean (standard deviation) PCFs in the unassisted, manually assisted following an MIC maneuver, MI-E-assisted, and manual thrust plus MI-E-assisted conditions were 95.7 (40.5), 155.9 (53.1), 177.2 (33.9), and 202.4 (46.6) L/min, respectively. All three interventions significantly improved PCF. However, manual assistance following an MIC maneuver was significantly less effective than MI-E alone. Manual thrust plus MI-E was significantly more effective than both of these interventions. CONCLUSION: In patients with NMD and respiratory muscle dysfunction, MI-E alone was more effective than manual assistance following an MIC maneuver. However, MI-E used in conjunction with manual thrust improved PCF even further.

A Comparison of Cough Assistance Techniques in Patients with Respiratory Muscle Weakness

PURPOSE: To assess the ability of a mechanical in-exsufflator (MI-E), either alone or in combination with manual thrust, to augment cough in patients with neuromuscular disease (NMD) and respiratory muscle dysfunction. MATERIALS AND METHODS: For this randomized crossover single-center controlled trial, patients with noninvasive ventilator-dependent NMD were recruited. The primary outcome was peak cough flow (PCF), which was measured in each patient after a cough that was unassisted, manually assisted following a maximum insufflation capacity (MIC) maneuver, assisted by MI-E, or assisted by manual thrust plus MI-E. The cough augmentation techniques were provided in random order. PCF was measured using a new device, the Cough Aid. RESULTS: All 40 enrolled participants (37 males, three females; average age, 20.9±7.2 years) completed the study. The mean (standard deviation) PCFs in the unassisted, manually assisted following an MIC maneuver, MI-E-assisted, and manual thrust plus MI-E-assisted conditions were 95.7 (40.5), 155.9 (53.1), 177.2 (33.9), and 202.4 (46.6) L/min, respectively. All three interventions significantly improved PCF. However, manual assistance following an MIC maneuver was significantly less effective than MI-E alone. Manual thrust plus MI-E was significantly more effective than both of these interventions. CONCLUSION: In patients with NMD and respiratory muscle dysfunction, MI-E alone was more effective than manual assistance following an MIC maneuver. However, MI-E used in conjunction with manual thrust improved PCF even further.

Pulmonary rehabilitation

Pulmonary rehabilitation consists of breathing retraining, respiratory muscle rest, airway secretion elimination, reconditioning exercise, psychosocial support, nutritional support, adequate ventilator support, and patient education. It is usually performed by using the appropriate inspiratory/expiratory muscle aids to alleviate and control the symptoms of respiratory diseases and to prevent respiratory complications. It is important to understand the principles of each technique and apply them properly in delivering pulmonary rehabilitation.

Comparison of Pulmonary Functions at Onset of Ventilatory Insufficiency in Patients With Amyotrophic Lateral Sclerosis, Duchenne Muscular Dystrophy, and Myotonic Muscular Dystrophy

OBJECTIVE: To evaluate pulmonary functions of patients with amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy (DMD), and myotonic muscular dystrophy (MMD) at the onset of ventilatory insufficiency. METHODS: This retrospective study included ALS, DMD, and MMD patients with regular outpatient clinic follow-up in the Department of Rehabilitation Medicine at Gangnam Severance Hospital before the application of non-invasive positive pressure ventilation (NIPPV). The patients were enrolled from August 2001 to March 2014. If patients experienced ventilatory insufficiency, they were treated with NIPPV, and their pulmonary functions were subsequently measured. RESULTS: Ninety-four DMD patients, 41 ALS patients, and 21 MMD patients were included in the study. The mean SpO2 was lower in the MMD group than in the other two groups. The mean forced vital capacity (FVC) in the supine position was approximately low to mid 20% on average in DMD and ALS patients, whereas it was 10% higher in MMD patients. ALS patients showed a significantly lower FVC in the supine position than in the sitting position. Maximal insufflation capacity, unassisted peak cough flow, maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP) were significantly higher in MMD group than in the other groups. MEP was significantly the lowest in DMD patients, followed by in ALS, and MMD patients, in order. CONCLUSION: Disease-specific values of pulmonary function, including FVC, MEP, and MIP, can be accurately used to assess the onset of ventilatory insufficiency in patients with ALS, DMD, and MMD.

Home Mechanical Ventilation in South Korea

PURPOSE: To survey the use of invasive and noninvasive home mechanical ventilation (HMV) methods in South Korea from the perspective of physical medicine and rehabilitation (PM&R). MATERIALS AND METHODS: For 413 users of HMV, retrospective reviews of PM&R interventions and survey of HMV methods employed from Mar 2000 to Dec 2009. RESULTS: Of the 413 users, the majority of whom with progressive neuromuscular disorders (NMDs) (n=358), 284 patients initially used noninvasive mechanical ventilation (NIV), while 63 others who were using tracheostomy mechanical ventilation switched to NIV as part of their rehabilitation. The NMD patients began HMV at an earlier age (34.9+/-20.3 yrs), and used for longer (14.7+/-7.5) hours than patients with non-neuromuscular causes of respiratory impairment. CONCLUSION: Noninvasive management was preferred over invasive ones, and transition to the former was a result of PM&R interventions.

Myocardial atrophy in children with mitochondrial disease and Duchenne muscular dystrophy / 소아과

PURPOSE: Mitochondrial disease (MD) and Duchenne muscular dystrophy (DMD) are often associated with cardiomyopathy, but the myocardial variability has not been isolated to a specific characteristic. We evaluated the left ventricular (LV) mass by echocardiography to identify the general distribution and functional changes of the myocardium in patients with MD or DMD. METHODS: We retrospectively evaluated the echocardiographic data of 90 children with MD and 42 with DMD. Using two-dimensional echocardiography, including time-motion (M) mode and Doppler measurements, we estimated the LV mass, ratio of early to late mitral filling velocities (E/A), ratio of early mitral filling velocity to early diastolic mitral annular velocity (E/Ea), stroke volume, and cardiac output. A "z score" was generated using the lambda-mu-sigma method to standardize the LV mass with respect to body size. RESULTS: The LV mass-for-height z scores were significantly below normal in children with MD (-1.02+/-1.52, P<0.001) or DMD (-0.82+/-1.61, P=0.002), as were the LV mass-for-lean body-mass z scores. The body mass index (BMI)-for-age z scores were far below normal and were directly proportional to the LV mass-for-height z scores in both patients with MD (R=0.377, P<0.001) and those with DMD (R=0.330, P=0.033). The LV mass-for-height z score correlated positively with the stroke volume index (R=0.462, P<0.001) and cardiac index (R=0.358, P<0.001). CONCLUSION: LV myocardial atrophy is present in patients with MD and those with DMD and may be closely associated with low BMI. The insufficient LV mass for body size might indicate deterioration of systolic function in these patients.

Successful Surgery for Scoliosis Supported by Pulmonary Rehabilitation in a Duchenne Muscular Dystrophy Patient With Forced Vital Capacity Below 10%

Low vital capacity is a risk factor for scoliosis correction operation in Duchenne muscular dystrophy (DMD) patients, but pulmonary rehabilitation, including noninvasive intermittent positive pressure ventilator application, air stacking exercise, and assisted coughing technique, reduces the pulmonary complications and perioperative mortality risk. In this case, the patient's preoperative forced vital capacity (FVC) was 8.6% of normal predicted value in sitting position and 9.4% in supine position. He started pulmonary rehabilitation before the operation and continued right after the operation. Scoliosis correction operation was successful without any pulmonary complications, and his discomfort in sitting position was improved. If pulmonary rehabilitative support is provided properly, FVC below 10% of normal predicted value is not a contraindication of scoliosis correction operation in DMD patients.