Won Ah Choi

How Respiratory Muscle Strength Correlates with Cough Capacity in Patients with Respiratory Muscle Weakness

Purpose The purpose of this study is to investigate how respiratory muscle strength correlates to cough capacity in patients with respiratory muscle weakness. Materials and Methods Forty-five patients with amyotrophic lateral sclerosis (ALS), 43 with cervical spinal cord injury (SCI), and 42 with Duchenne muscular dystrophy (DMD) were recruited. Pulmonary function tests including forced vital capacity (FVC) and respiratory muscle strength (maximal expiratory pressure, MEP; maximal inspiratory pressure, MIP) were performed. The correlation between respiratory muscle strength and cough capacity was analyzed. Results In the SCI group, FVC in a supine position (2,597 ± 648 mL) was significantly higher than FVC in a sitting position (2,304 ± 564 mL, p < 0.01). Conversely, in the ALS group, FVC sitting (1,370 ± 604 mL) was significantly higher than in supine (1,168 ± 599 mL, p < 0.01). In the DMD group, there was no statistically significant difference between FVC while sitting (1,342 ± 506 mL) and FVC while supine (1,304 ± 500 mL). In addition, the MEP and MIP of all three groups showed a significant correlation with peak cough flow (PCF) (p < 0.01, Pearsons correlation analysis). In the SCI group, MIP was more closely correlated with PCF, while in the ALS and DMD groups, MEP was more closely correlated with PCF (p < 0.01, multiple regression analysis). Conclusion To generate cough flow, inspiratory muscle strength is significantly more important for SCI patients, while expiratory muscle function is significantly more important for ALS and DMD patients.

Accuracy of blind versus ultrasound-guided suprapatellar bursal injection

To compare the accuracy rates between ultrasound (US)‐guided and blind knee intra‐articular injection via the suprapatellar bursa.

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.

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.

Cough assistance device for patients with glottis dysfunction and/or tracheostomy.

OBJECTIVE To estimate the efficiency of a cough assistance device, the Cough Aid, in patients with weak respiratory muscles with bulbar palsy and/or tracheostomy. The Cough Aid is a device that has been developed to substitute for glottis function. DESIGN Before-after trial. SUBJECTS/PATIENTS A total of 74 patients with bulbar palsy and/or tracheostomy, as well as respiratory muscle weakness, were recruited. METHODS Forced vital capacity, unassisted cough peak flow, lung insufflation capacity, and assisted cough peak flow were measured via tracheostomy or oronasal interface. Lung insufflation capacity and assisted cough peak flow were measured using the Cough Aid. RESULTS AND CONCLUSION In all 74 subjects, lung insufflation capacities measured with the device were significantly higher than forced vital capacities (p < 0.01). Assisted cough peak flows measured using the device were also significantly higher than unassisted cough peak flows (p < 0.01). The Cough Aid is effective in helping to increase cough flow and assisting in the air stacking exercise by substituting the function of the glottis in patients who have glottis dysfunction or a tracheostomy tube.

Sleep Transcutaneous vs. End-Tidal CO2 Monitoring for Patients with Neuromuscular Disease.

ObjectiveThis study compared transcutaneous carbon dioxide partial pressure (PtcCO2) and end-tidal carbon dioxide partial pressure (PetCO2) monitoring during sleep for patients with neuromuscular disease. DesignThis is a retrospective study of patients whose PtcCO2 and PetCO2 were monitored before they began using noninvasive mechanical ventilation. The outcomes were divided into four groupings: group 1, both PtcCO2 and PetCO2 are greater than or equal to 49 mm Hg; group 2, PtcCO2 is greater than or equal to 49 mm Hg but PetCO2 is less than 49 mm Hg; group 3, PtcCO2 is less than 49 mm Hg but PetCO2 is greater than or equal to 49 mm Hg; and group 4, both PtcCO2 and PetCO2 are less than 49 mm Hg. ResultsA total of 39 subjects (mean [SD] age, 27.7 [19.3] yrs) were enrolled. PtcCO2 values were significantly higher than PetCO2 values (P < 0.001). The intraclass correlation coefficient between maximal and mean values of PtcCO2 and PetCO2 was 0.612 and 0.718, respectively. Bias and limits of agreement between PtcCO2 and PetCO2 were −7.5 mm Hg and −21.3 to 6.3 mm Hg for maximal values and −4.8 mm Hg and −14.8 to 5.3 mm Hg for mean values. Group 2 included 19 (48.7%) and group 3 included 3 (7.6%) patients who showed discrepancy of hypercapnia between two methods. ConclusionsMaximum PtcCO2 was significantly greater than maximum PetCO2 for both groups and, therefore, tends to be higher than PetCO2 in this population. This should be taken into consideration when assessing patients for sleep hypoventilation.

Postural vital capacity difference with aging in duchenne muscular dystrophy

Introduction: A change in vital capacity (VC) from standing to supine can be an index of diaphragm paralysis if it exceeds 25%. We aimed to verify whether the postural VC difference increases with age and reflects diaphragm weakness in DMD. Methods: VCs were measured in DMD. Postural VC difference and percentage were calculated from the VC data. Maximal inspiratory pressure (MIP) and MIP percentage were measured as an indirect index of diaphragm weakness. Results: A total of 220 patients and 544 measurements were collected. MIP and MIP percentage decreased significantly with age (P < 0.001 for both). Estimated postural VC difference and percentage also decreased (P < 0.001, P = 0.006, respectively). Age group comparisons showed a significant decrease in younger, but not older subjects. Conclusions: This study shows that the postural VC difference tended to decrease with age and might not reflect diaphragmatic weakness in DMD; however, this should be interpreted cautiously. Muscle Nerve 52: 722–727, 2015

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 patients 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.

The Significance of Transcutaneous Continuous Overnight CO(2) Monitoring in Determining Initial Mechanical Ventilator Application for Patients with Neuromuscular Disease.

Objective To reveal the significance of continuous transcutaneous carbon dioxide (CO2) level monitoring through reviewing cases which showed a discrepancy in CO2 levels between arterial blood gas analysis (ABGA) and continuous transcutaneous blood gas monitoring. Method Medical record review was conducted retrospectively of patients with neuromuscular diseases who had started home mechanical ventilation between June 2008 and May 2010. The 89 patients underwent ABGA at the 1st hospital day, and changes to their CO2 level were continuously monitored overnight with a transcutaneous blood gas analysis device. The number of patients who initially appeared to show normal PaCO2 through ABGA, yet displayed hypercapnea through overnight continuous monitoring, was counted. Results 36 patients (40.45%) presented inconsistent CO2 level results between ABGA and continuous overnight monitoring. The mean CO2 level of the 36 patients using ABGA was 37.23±5.11 mmHg. However, the maximum and mean CO2 levels from the continuous monitoring device were 52.25±6.87 mmHg and 46.16±6.08 mmHg, respectively. From the total monitoring period (357.28±150.12 minutes), CO2 retention over 45 mmHg was detected in 198.97 minutes (55.69%). Conclusion Although ABGA only reflects ventilatory status at the puncturing moment, ABGA results are commonly used to monitor ventilatory status in most clinical settings. In order to decide the starting point of home mechanical ventilation in neuromuscular patients, continuous overnight monitoring should be considered to assess latent CO2 retention.

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.