Pico de fluxo de tosse em crianças e jovens com atrofia muscular espinhal tipo II e tipo III / El pico flujo de tos en niños y jóvenes con atrofia muscular espinal tipo II y III / Peak cough flow in children and young people with spinal muscular atrophy types II and III

RESUMO A atrofia muscular espinhal é uma doença neurodegenerativa, que pode cursar com insuficiência respiratória progressiva. O objetivo deste trabalho é descrever o pico de fluxo de tosse de crianças e jovens com atrofia muscular espinhal dos tipos II e III. Trata-se de um estudo transversal descritivo realizado em ambulatório de neuropediatria entre março de 2011 e maio de 2012, com pacientes com atrofia muscular e espinhal dos tipos II e III com mais de 5 anos de idade. Dos 53 pacientes elegíveis, 21 participaram da pesquisa. A medição do pico de fluxo de tosse foi realizada através do peak flow meter com os pacientes sentados e deitados. Após registradas três medidas, foi selecionada a maior entre elas. Os indivíduos do tipo III alcançaram valores de pico de fluxo de tosse superiores aos dos indivíduos do tipo II. As medidas tomadas em posição sentada (AME tipo II 159,4 l/min; AME tipo III 287,9 l/min) foram superiores às medidas em posição deitada (AME tipo II 146,9 l/min; AME tipo III 257,5 l/min), com diferença significativa (p-valor=0,008 posição sentada e p=0,033 posição deitada). Concluiu-se que indivíduos com AME tipo III apresentam maior PFT, principalmente quando sentados, em comparação com o tipo II.

RESUMEN La atrofia muscular espinal es una enfermedad neurodegenerativa, que puede presentarse con insuficiencia respiratoria progresiva. Este trabajo pretende describir el pico flujo de tos de niños y jóvenes con atrofia muscular espinal tipo II y III. Se trata de un estudio descriptivo transversal realizado en la clínica ambulatoria de neuropediatría entre marzo de 2011 y mayo de 2012, con los pacientes con más de 5 años de edad con atrofia muscular espinal tipo II y III. De los 53 pacientes elegibles, 21 participaron del estudio. La medición del pico flujo de tos se llevó a cabo a través de peak flow meter en pacientes en la posición sentada y supina. Después del registro de las tres medidas, se seleccionó la mayor. Los individuos con tipo III tuvieron valores pico flujo de tos mayores que los con tipo II. Las medidas registradas en la posición sentada (AME tipo II 159,4 l/min; AME tipo III 287,9 l/min) fueron las más altas que la de posición supina (AME tipo II 146,9 l/min; AME tipo III 257,5 l/min), con diferencias significativas (p-valor=0,008 posición sentada y p=0,033 posición supina). Se concluyó que los individuos con AME tipo III presentan mayor PFT, especialmente en la posición sentada, comparados con los de tipo II.

ABSTRACT Spinal muscular atrophy is a neurodegenerative disorder, which may be associated with progressive respiratory failure. Our aim is to describe the peak cough flow of children and young people with spinal muscular atrophy types II and III. This is a descriptive, cross-sectional study conducted at a neuropediatrics outpatient clinic between March 2011 and May 2012, with patients with spinal muscular atrophy types II and III, and aging more than 5 years. Out of the 53 eligible patients, 21 participated in the research. The measurement of peak cough flow was carried out through the peak flow meter, with patients sitting and lying down. After taking three measures, we selected the one with the highest value among them. Type-III individuals reached peak cough flow values higher than those of type-II individuals. Measures taken in the sitting position (SMA II 159.4 l/min; SMA III 287.9 l/min) were higher than those measured in the lying position (SMA II 146.9 l/min; SMA III 257.5 l/min), with significant difference (p-value=0.008 in sitting position, and p=0.033 in lying position). We concluded that individuals with SMA III manifest higher PCF, especially when sitting, in comparison with SMA II.

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.

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.

Clinical Implication of Air Stacking Exercise in Patients with Neuromuscular Diseases

OBJECTIVE: To evaluate the effect of the air stacking exercise on maximal insufflation capacity (MIC) and peak cough flow (PCF) in patients with neuromuscular diseases. METHOD: Two hundred twenty nine neuromuscular patients with vital capacity (VC) below 50% of the predicted normal value were initially evaluated for VC, MIC, PCF, and assisted PCF (APCF). After the first evaluation, these patients were instructed to carry out air stacking exercise periodically, and were re-evaluated after one year. RESULTS: Forty seven patients were capable of performing air stacking exercise on regular basis, at least twice a day for one year. Among these patients, MIC increased in 28 patients from 1345.4 ml to 1572.9 ml on average (p<0.05), while it decreased in 19 patients from 1740.0 ml to 1325.3 ml on average (p<0.05). In the increasing MIC group APCF increased from 244.6 L/min to 278.1 L/min (p<0.05). In the decreasing MIC group, every value decreased significantly. CONCLUSION: Air stacking exercise was shown to be capable of increasing MIC and APCF despite the reduction in VC and PCF in patients with neuromuscular diseases.

Respiratory Muscle Strength and Cough Capacity in Patients with Duchenne Muscular Dystrophy

The function of inspiratory muscles is crucial for effective cough as well as expiratory muscles in patients with Duchenne muscular dystrophy (DMD). However, there is no report on the correlation between cough and inspiratory muscle strength. To investigate the relationships of voluntary cough capacity, assisted cough techniques, and inspiratory muscle strength as well as expiratory muscle strength in patients with DMD (n=32). The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and three different techniques of assisted PCF were evaluated. The mean value of MICs (1918 +/- 586 mL) was higher than that of VCs (1474 +/- 632 mL) (p < 0.001). All three assisted cough methods showed significantly higher value than unassisted method (212 +/- 52 L/min) (F = 66.13, p < 0.001). Combined assisted cough technique (both manual and volume assisted PCF; 286 +/- 41 L/min) significantly exceeded manual assisted PCF (MPCF; 246 +/- 49 L/ min) and volume assisted PCF (VPCF; 252 +/- 45 L/min) (F = 66.13, p < 0.001). MIP (34 +/- 13 cmH2O) correlated significantly with both UPCF and all three assisted PCFs as well as MEP (27 +/- 10 cmH2O) (p < 0.001). Both MEP and MIP, which are the markers of respiratory muscle weakness, should be taken into account in the study of cough effectiveness.

Assisted Cough and Pulmonary Compliance in Patients with Duchenne Muscular Dystrophy

The aim of this study was to investigate the factors affecting cough ability, and to compare the assisted cough methods in patients with Duchenne muscular dystrophy (DMD). A total seventy-one male patients with DMD were included in the study. The vital capacity (VC) and maximum insufflation capacity (MIC) were measured. The unassisted peak cough flow (UPCF) and three different techniques of assisted peak cough flow were evaluated. UPCF measurements were possible for all 71 subjects. But when performing the three different assisted cough techniques, peak cough flows (PCFs) could be obtained from only 51 subjects. The mean value of MICs (1801+/-780cc) was higher than that of VCs (1502+/-765cc) (p< 0.01). All three assisted cough methods showed a significantly higher value than the unassisted method (F=80.92, p< 0.01). The manual assisted PCF under MIC (MPCFmic) significantly exceeded those produced by manual assisted PCF (MPCF) or PCF under MIC (PCFmic). The positive correlation between the MIC, VC difference (MIC-VC), and the difference between PCFmic and UPCF (PCFmic-UPCF) was seen (r= 0.572, p< 0.01). The preservation of pulmonary compliance is important for the development of an effective cough as well as assisting the compression and expulsive phases. Thus, the clinical importance of the inspiratory phase and pulmonary compliance in assisting a cough should be emphasized.

New Device for Improving Cough Function: Through Assisting Glottic Function

OBJECTIVE: The patients with glottic dysfunction cannot cough effectively. It is difficult to eliminate pulmonary secretions and to provide lung expansion exercise in those patients. Thus we made a device which substitutes the function of glottis and examines the effectiveness of the external glottic function of the device. METHOD: This new device was made of two parts: connection and control part. Connection part had three ports: patient connection, insufflation and connection port. The insufflation port with one-way valve allows additional air stacking using a manual resuscitation bag after a patients's deep inspiration. Control part had external glottic function by air flow control with button pushing simply. The vital capacity (VC), maximal insufflation capacity (MIC), MIC with device (MICdevice), unassistive peak cough flow (UPCF), assistive peak cough flow (APCF) and assistive peak cough flow with device (APCFdevice) were measured in six patients. RESULTS: In tested patients, four were amyotrophic lateral sclerosis patients and two were cervical spinal cord injury patients with tracheostomized. The value of MICdevice or APCFdevice was higher than MIC or APCF in all patients. CONCLUSION: This new device can improve the bronchial toileting by improving cough function and also provide lung expansion exercise effectively in patients with glottic dysfunction.

Analysis of Pulmonary Mechanics and the Factors for Coughing in Duchenne Muscular Dystrophy

OBJECTIVE: To investigate the pathologic pulmonary mechanics and analyze the factors affecting cough ability in patients with Duchenne muscular dystrophy (DMD). METHOD: Thirty-one patients with DMD were investigated. The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory (MIP), and expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and assisted PCF at three different conditions were evaluated. RESULTS: The mean value of MICs (1, 873 +/- 644 cc) was higher than that of VCs (1, 509 +/- 640 cc). MIP and MEP were 48.8 +/- 21.4% and 29.5 +/- 19.5% of predicted normal value respectively. MIP was correlated with UPCFs as well as MEP. All of three assisted cough methods showed significantly higher value than unassisted method (p<0.01). The manual assisted PCFs at MIC significantly exceeded those produced by manual assisted or PCFs at MIC. The positive correlation between the MIC-VC difference and PCF at MIC-UPCF difference was seen (p<0.01). CONCLUSION: Inspiratory muscle strength and the preservation of pulmonary compliance is important for the development of effective cough as well as expiratory muscle power. Thus, the clinical implication of the inspiratory phase in assisting a cough should be emphasized.

The Relationships of Coughing to the Respiratory Muscle Strength and Pulmonary Compliance in Tetraplegic Patients

OBJECTIVE: To analyze the factors influencing the capacity of cough, the relationships between maximal respiratory pressure, lung compliance, capacity of cough, and assisted cough techniques were evaluated in tetraplegics. METHOD: The vital capacity (VC) in seated and supine position, maximum insufflation capacity (MIC), maximum inspiratory (MIP) and expiratory (MEP) pressure in seated position were measured. Unassisted and assisted peak cough flow (PCF) at two different conditions (a volume assisted method by the mechanical insufflation [PCFmic] and the manual assistance by abdominal compression [MPCF]) were evaluated in 44 tetraplegic patients. RESULTS: The mean value of VC in supine was greater than that of seated position (p<0.01). The MICs of the subjects were significantly higher than VCs in a same position (<0.01). Both volume and manual assisted method showed significantly higher PCF than unassisted PCF (p<0.01). MIP (r=0.53) correlated with UPCF as well as MEP (r=0.68), although MEP was better correlated with UPCF. CONCLUSION: Generally the therapists apply manual pressure only to increase capacity of cough, which assist the expulsive phase. The results of this study showed that both inspiratory and expulsive phases should be assisted to enhance the effectiveness of cough.