A comparison of peak cough flow and peak expiratory flow in children with neuromuscular disorders.

Spirometry and peak cough flow testing (PCF) are commonly used in the respiratory assessment of children with a neuromuscular disorder (NMD). Testing uses two different machines, increases laboratory time, costs and resource utilisation. No studies have assessed the correlation between peak expiratory flow (PEF) obtained from spirometry and PCF in children with NMD using one device. An audit of children with a NMD managed at the Children's Hospital at Westmead in 2022-2024 aged < 20 years who performed spirometry and PCF testing on the same device (Vyaire Body BoxTM, Ultrasonic flow meter-based, or Vyaire PneumotachographTM, Pneumotach flow meter-based; Germany) was conducted to assess the correlation between PCF and PEF. Fifty-one sets of testing were identified, and 40 subjects (9F) had reproducible testing and were included. Median (range) age was 14.95 (7.20-19.00) years. Median PEF (L/min) was 4.05 (1.22-10.26) and median PCF (L/min) was 4.29 (1.69-10.82). PEF and PCF had a strong Pearson's correlation coefficient, (R = 0.97, p = 0.03). The coefficient of determination was 0.93. If laboratory resources permit, spirometry should be the test of choice for children with NMD. On average, spirometry required multiple practices to achieve reproducibility to meet ATS/ERS standards. PCF testing can be utilised for children where performing technically acceptable spirometry is not possible.

Pulmonary function tests for evaluating the severity of Duchenne muscular dystrophy disease.

AIM: In Duchenne muscular dystrophy (DMD), lung disease contributes significantly to morbidity and mortality. This study aimed to assess the usefulness of various pulmonary function tests in evaluating DMD severity. METHODS: This retrospective study analysed lung function tests of patients with DMD-treated in the multidisciplinary respiratory neuromuscular clinic at Schneiders' Children Medical Center of Israel. Data were analysed according to age, ambulatory status and glucocorticoid treatment. RESULTS: Among 90 patients with DMD, 40/63 (63.5%) ambulatory patients and 22/27 (81.5%) nonambulatory patients successfully performed spirometry. Significant annual declines were demonstrated among nonambulatory patients, in percentile predicted forced vital capacity (3.8%) and in total lung capacity (5.5%) per year. The decline correlated with age and loss of ambulation but not with steroid treatment. Peak cough flow values were randomly distributed and did not correlate with age, ambulation or treatment. In nonambulatory patients, transcutaneous carbon dioxide measurement correlated significantly with age (r = 0.55, p = 0.02). CONCLUSION: Forced vital capacity, total lung capacity and transcutaneous carbon dioxide correlated with the clinical severity of disease in children with DMD. These measures may be useful in follow-up and clinical trials. A comparable correlation was not found for peak cough flow.

Cut-Off Value of Voluntary Peak Cough Flow in Patients with Parkinson's Disease and Its Association with Severe Dysphagia: A Retrospective Pilot Study.

Background and Objectives. Swallowing and coughing reflexes are both closely associated with airway protection. Peak cough flow (PCF) is associated with dysphagia in several neurogenic diseases. In this study, we aimed to analyze the relationship between PCF and aspiration in Parkinson's disease (PD) and determine the cut-off value of PCF. Materials and Methods. We retrospectively analyzed the records of patients with PD who underwent a videofluoroscopic swallowing study and checked for PCF. A total of 219 patients were divided into an aspiration group (n = 125) and a non-aspiration group (n = 94). Results. Significantly lower PCF values were observed in the aspiration group compared to the non-aspiration group (132.63 ± 83.62 vs. 181.38 ± 103.92 L/min, p < 0.001). Receiver operating characteristic curve analysis revealed that a PCF cut-off value of 153 L/min (area under the receiver operating characteristic curve, 0.648; sensitivity, 73.06%; specificity, 51.06%) was associated with aspiration in PD. Additionally, a univariate analysis showed that the male sex, lower body mass indexes, higher Hoehn and Yahr scales, and PCF values of ≤153 L/min indicated an increased risk of aspiration. Conclusions. Through a multivariate analysis, we demonstrated that a PCF value ≤153 L/min was associated with an increased risk of aspiration (odds ratio 3.648; 1.797-7.407), highlighting that a low PCF is a risk factor for aspiration in patients with PD.

A New Therapeutic Approach for Dystussia and Atussia in Neurogenic Dysphagia: Effect of Aerosolized Capsaicin on Peak Cough Flow.

Swallowing and cough are crucial components of airway protection. In patients with neurogenic dysphagia (ND), there is a high prevalence of dystussia (impaired cough) and atussia (absence of cough). As a result, the ability to detect and remove aspirated material from the airway decreases, exacerbating the sequelae associated with ND, including aspiration pneumonia, a leading cause of mortality in ND. This controlled intervention study aimed to quantify the cough response to aerosolized capsaicin (AC) in patients with ND and assess the potential of AC as a therapeutic tool in treating ND-related dystussia and atussia. Furthermore, we propose a novel application method that enables AC treatment to be performed at home. Spirometry was used to measure peak cough flow (PCF) of voluntary cough (cough on command) and reflexive cough (cough secondary to pharyngeal exposure to AC) in 30 subjects with and 30 without ND. The capsaicin aerosol was generated by adding 1-10 drops of liquid cayenne extract (1.5-2% capsaicin) to 100 mL carbonated water (0.00075-0.001% to 0.0075-0.01% capsaicin). Voluntary PCF in the ND group was significantly lower than in the control group (p < 0.001), while there was no significant difference in reflexive PCF (p = 0.225). Within the ND group, reflexive PCF was significantly higher than voluntary PCF (p = 0.001), while in healthy controls, reflexive PCF was significantly lower (p < 0.001). The data show that AC increased the tracheobronchial clearance efficacy in ND patients with dystussia and atussia, as it enabled subjects to access their individual cough potential, which is present, but inaccessible, due to neurological disorder.

Tracheostomy, ventilatory wean, and decannulation in COVID-19 patients.

PURPOSE: COVID-19 patients requiring mechanical ventilation can overwhelm existing bed capacity. We aimed to better understand the factors that influence the trajectory of tracheostomy care in this population to facilitate capacity planning and improve outcomes. METHODS: We conducted an observational cohort study of patients in a high-volume centre in the worst-affected region of the UK including all patients that underwent tracheostomy for COVID-19 pneumonitis ventilatory wean from 1st March 2020 to 10th May 2020. The primary outcome was time from insertion to decannulation. The analysis utilised Cox regression to account for patients that are still progressing through their tracheostomy pathway. RESULTS: At the point of analysis, a median 21 days (IQR 15-28) post-tracheostomy and 39 days (IQR 32-45) post-intubation, 35/69 (57.4%) patients had been decannulated a median of 17 days (IQR 12-20.5) post-insertion. The overall median age was 55 (IQR 48-61) with a male-to-female ratio of 2:1. In Cox regression analysis, FiO2 at tracheostomy ≥ 0.4 (HR 1.80; 95% CI 0.89-3.60; p = 0.048) and last pre-tracheostomy peak cough flow (HR 2.27; 95% CI 1.78-4.45; p = 0.001) were independent variables associated with prolonged time to decannulation. CONCLUSION: Higher FiO2 at tracheostomy and higher pre-tracheostomy peak cough flow are associated with increased delay in COVID-19 tracheostomy patient decannulation. These finding comprise the most comprehensive report of COVID-19 tracheostomy decannulation to date and will assist service planning for future peaks of this pandemic.

Peak Cough Flow in Children with Neuromuscular Disorders.

PURPOSE: Patients with neuromuscular disease (NMD) experience weakened cough due to progressive respiratory muscle weakness. Peak cough flow (PCF) measurements derived from adult populations are used to recommend initiation of assisted cough therapies. The objective of this study was to characterize PCF values among pediatric patients with NMD. METHODS: Retrospective chart review was performed for patients seen in the multidisciplinary pediatric muscular dystrophy clinic from 2010 to 2016. Clinical and demographic variables included age, gender, ambulation status, and PCF measurements. RESULTS: 366 patients with an established diagnosis of NMD (median age 11.8 years) were included in this study. 102 (27.8%) out of the 366 patients were affected by Duchenne muscular dystrophy (DMD), 42 (11.5%) by congenital muscular dystrophy (CMD), 42 (11.5%) by Charcot Marie Tooth disease (CMT) and 24 (6.5%) by Becker's muscular dystrophy (BMD). The mean PCF values in DMD (255.8 L/min) and CMD (249.1 L/min) were lower than CMT (321.5 L/min) with p-values of 0.007 and 0.02, respectively. The mean PCF of BMD (333.3 L/min) was higher than that of DMD and CMD but the difference was not statistically significant. PCFs were not statistically different between ambulatory and non-ambulatory status (263.0 L/min versus 290.8 L/min, p = 0.12). Children under 10 years of age had lower PCF relative to older subjects (179.5 L/min versus 300.9 L/min, p < 0.0001). CONCLUSION: Baseline PCF values in young children are below the adult-specific values suggested for starting assisted cough techniques. Further longitudinal trials are required to derive pediatric-specific reference values for PCF in patients with NMD.

Cough and airway clearance in Duchenne muscular dystrophy.

People with Duchenne muscular dystrophy (DMD), develop a respiratory muscle weakness that results in weakened cough, airway clearance impairment and over time respiratory failure and death. Assessment of cough effectiveness through vital capacity, peak cough flow and maximal inspiratory and expiratory pressures has been used to identify the optimal timing of cough augmentation techniques initiation. The choice of therapies depends on physician knowledge, and patient/care giver abilities. The purpose of this review is to clarify mechanisms of action, benefits and disadvantages of available techniques, such as manual cough-assisting manoeuvres, glossopharyngeal breathing, air stacking by resuscitator bag or by volume-cycle ventilator, and mechanical insufflator-exsufflator. Mechanisms of mucus mobilization, like intrapulmonary percussive ventilation, may have a therapeutic role in the case of persistent atelectasis. It is also crucial to recognize the initial phase of an acute respiratory exacerbation, increase the use of these techniques which may reduce morbidity and mortality.

A novel reflex cough testing device.

BACKGROUND: The reflex cough test is useful for detecting silent aspiration, a risk factor for aspiration pneumonia. However, assessing the risk of aspiration pneumonia requires measuring not only the cough reflex but also cough strength. Currently, no reflex cough testing device is available that can directly measure reflex cough strength. We therefore developed a new testing device that can easily and simultaneously measure cough strength and the time until the cough reflex, and verified whether screening with this new instrument is feasible for evaluating the risk of aspiration pneumonia. METHODS: This device consists of a special pipe with a double lumen, a nebulizer, and an electronic spirometer. We used a solution of prescription-grade L-tartaric acid to initiate the cough reflex. The solution was inhaled through a mouthpiece as a microaerosol produced by an ultrasonic nebulizer. The peak cough flow (PCF) of the induced cough was measured with the spirometer. The 70 patients who participated in this study comprised 49 patients without a history of pneumonia (group A), 21 patients with a history of pneumonia (group B), and 10 healthy volunteers (control group). RESULTS: With the novel device, PCF and time until cough reflex could be measured without adverse effects. The PCF values were 118.3 ± 64.0 L/min, 47.7 ± 38.5 L/min, and 254.9 ± 83.8 L/min in group A, group B, and the control group, respectively. The PCF of group B was significantly lower than that of group A and the control group (p < 0.0001), while that of group B was significantly lower than that of the control group (p < 0.0001). The time until the cough reflex was 4.2 ± 5.9 s, 7.0 ± 7.0 s, and 1 s in group A, group B, and the control group, respectively. This duration was significantly longer for groups A and B than for the control group (A: p < 0.001, B: p < 0.001), but there was no significant difference between groups A and B (p = 0.0907). CONCLUSION: Our newly developed device can easily and simultaneously measure the time until the cough reflex and the strength of involuntary coughs for assessment of patients at risk of aspiration pneumonia.

Relation between hand grip strength, respiratory muscle strength and spirometric measures in male nursing home residents.

Adverse-outcomes related to sarcopenia are mostly mentioned as physical disability. As the other skeletal muscles, respiratory muscles may also be affected by sarcopenia. Respiratory muscle strength is known to affect pulmonary functions. Therefore, we aimed to investigate the relations between extremity muscle strength, respiratory muscle strengths and spirometric measures in a group of male nursing home residents. Among a total of 104 male residents, residents with obstructive measures were excluded and final study population was composed of 62 residents. Mean age was 70.5 ± 6.7 years, body mass index: 27.7 ± 5.3 kg/m2 and dominant hand grip strength: 29.7 ± 6.5 kg. Hand grip strength was positively correlated with maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) (r = 0.35, p < 0.01 and r = 0.26, p < 0.05, respectively). In regression analysis, the only factor related to MIP was hand grip strength; among spirometric measures only parameter significantly related to grip strength was peak cough flow (PCF). The association of PCF with grip strength disappeared when MIP alone or "MIP and MEP" were included in the regression analysis. In the latter case, PCF was significantly associated only with MIP. We found peripheric muscle strength be associated with MIP and PCF but not with MEP or any other spirometric parameters. The relation between peripheral muscle strength and PCF was mediated by MIP. Our findings suggest that sarcopenia may affect inspiratory muscle strength earlier or more than the expiratory muscle strength. Sarcopenia may cause decrease in PCF in the elderly, which may stand for some common adverse respiratory complications.

Prediction of cough effectiveness in amyotrophic lateral sclerosis patients assessed by ultrasuond of the diaphragm during the cough expiration phase.

Assessing cough effectiveness, using Cough Peak Flow, is crucial for patients with Neuromuscular Diseases, such as Amyotrophic Lateral Sclerosis. Impaired cough function can contribute to respiratory decline and failure. The goal of the study is to determine the correlation between diaphragmatic excursion and cough expiratory phase, potentially utilizing ultrasonographic indices to estimate Cough Peak Flow in these patients. Twenty-two patients were enrolled in this study. The upward displacement of the diaphragm was measured with ultrasonography during voluntary cough expiration and Cough Peak Flow was simultaneously measured. A multivariable linear regression model was built to quantify the association between Cough Peak Flow and diaphragm expiratory excursion. There is significative relationship between Cough Peak Flow and diaphragm excursion with a Pearson's r coefficient of 0.86 observed in the patients group. Multiple linear regression analysis for Cough Peak Flow (Adjusted R2 = 0.86) revealed significant associations between Cough Peak Flow and expiratory excursion (adjusted ß-coefficient: 64.78, 95 %, CI: 51.50-78.07, p<0.001) and sex (adjusted ß-coefficient: -69.06; 95 % CI: -109.98 to -28.15, p=0.001). Our results predict the cough effectiveness by using M-mode diaphragmatic sonography with a potentially significant impact on therapeutic choices.

Waves of Precision: A Practical Guide for Reviewing New Tools to Evaluate Mechanical In-Exsufflation Efficacy in Neuromuscular Disorders.

Mechanical insufflation-exsufflation (MI-E) is essential for secretion clearance, especially in neuromuscular disorders. For the best outcomes, initiation of MI-E should be started at the correct time with regular evaluation to the response to treatment. Typically, cough peak flow has been used to evaluate cough effectiveness with and without MI-E. This review highlights the limitations of this and discussed other tools to evaluate MI-E efficacy in this rapidly developing field. Such tools include the interpretation of parameters (like pressure, flow and volumes) that derive from the MI-E device and external methods to evaluate upper airway closure. In this review we pinpoint the differences between different devices in the market and discuss new tools to better titrate MI-E and detect pathological responses of the upper airway. We discuss the importance of point of care ultrasound (POCUS), transnasal fiberoptic laryngoscopy and wave form analysis in this setting. To improve clinical practice newer generation MI-E devices should allow real-time evaluation of waveforms and standardize some of the derived parameters.

Correlation between voluntary cough and laryngeal cough reflex flows in patients with traumatic brain injury.

OBJECTIVE: To correlate voluntary cough and laryngeal cough reflex (LCR) flows in patients with traumatic brain injury (TBI). DESIGN: Cross-sectional study. SETTING: University rehabilitation hospital. PARTICIPANTS: Patients with TBI (n=25) and healthy controls (n=48). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak cough flows (PCFs) and LCR flows were measured using a peak flow meter at the oral-nasal interface. The largest value of 3 attempts was recorded for PCF and LCR, respectively. LCR was elicited by 20% solution of pharmaceutic-grade citric acid dissolved in sterile .15M NaCl solution that was inhaled from a nebulizer. RESULTS: PCF was 447.4 ± 99.0 L/min in the control group and 211.7 ± 58.2 L/min in the patient group. LCR was 209.2 ± 63.8L/min in the control group and 170.0 ± 59.7 L/min in the patient group. Both PCF (P=.000) and LCR (P=.013) were significantly reduced in patients with TBI compared to that of the control group. LCR was strongly related to the PCF in both control (R=.645; P=.000) and patient (R=.711; P=.000) groups. CONCLUSIONS: As LCR can be measured as a numerical value and significantly correlates with PCF, LCR can be used to estimate cough ability of patients with TBI who cannot cooperate with PCF measurement.

Effect of the Inspiratory Method and Timing of Voluntary Cough on Peak Cough Flow.

OBJECTIVE: To define the effect of the inspiratory method and cough timing on peak cough flow (PCF). METHODS: We investigated the effect of measurement conditions on PCF in healthy subjects (n=10). We then compared obstructive and restrictive pulmonary diseases (n=20) to assess for similar results in respiratory diseases. The PCF was measured under four conditions: before coughing, without maneuver 1 or with maneuver 2 a temporary respiratory pause (4-6 seconds) after rapid inspiration, and without maneuver 3 or with maneuver 4 a temporary respiratory pause after slow inspiration. After the measurements were completed, the PCF between the four conditions was compared for each subject group, and the effect size was calculated. RESULTS: PCF of maneuvers 1 and 3 were significantly higher than maneuver 4 in healthy subjects (476.34±102.05 L/min and 463.44±107.14 L/min vs. 429.54±116.83 L/min, p<0.01 and p<0.05, respectively) and patients with restrictive pulmonary disease (381.96±145.31 L/min, 354.60±157.36 L/min vs. 296.94±137.49 L/min, p<0.01 and p<0.05, respectively). In obstructive pulmonary disease, maneuver 1 was significantly higher than maneuver 4 (327.42±154.73 L/min vs. 279.48±141.10 L/min, p<0.05). The largest effect sizes were shown by maneuvers 4 and 1. CONCLUSION: PCF depends on changes in inspiratory speed before coughing and on temporary respiratory pauses after maximal inspiration. It will become necessary to unify the measurement methods for coughing strength and present appropriate coughing methods.

Expiratory Muscle Strength Training in Multiple System Atrophy: A Pilot Study.

Background: The effects of expiratory muscle strength training (EMST) has not yet been investigated in MSA patients. Objective: The primary objective was to test the effects of EMST on expiratory muscle strength and voluntary peak cough flow (vPCF) in patients with multiple system atrophy (MSA). The secondary objective was to assess the suitability of the pulmonary dysfunction index as a tool for identifying MSA patients with expiratory muscle weakness and reduced voluntary peak cough flow. Methods: This was an open label, non-controlled study, with an 8-week intensive home-based EMST protocol. The outcome measures included: maximal expiratory pressure (MEP) and vPCF. The sensitivity and specificity of the index of pulmonary dysfunction in the respiratory diagnostic process were assessed using receiver operating characteristic (ROC) analysis. Results: Fifteen MSA patients were enrolled in the study. Twelve MSA patients completed the training period. After the training period, MEP significantly increased (P = 0.006). Differences in vPCF were not significant (P = 0.845). ROC analysis indicated that the overall respiratory diagnostic accuracy of the index of pulmonary dysfunction had an outstanding capability to detect patients at risk of less effective coughing and an acceptable capability of detecting patients with decreased expiratory muscle strength. Conclusions: These findings indicate non-significant differences in vPCF after 8 weeks of EMST. The index of pulmonary dysfunction appears to be a promising prognostic screening tool for identifying altered cough efficacy in MSA patients. Test cut-offs may be used to select an appropriate respiratory physiotherapy technique.

Deterioration of Cough, Respiratory, and Vocal Cord Functions in Patients with Multiple System Atrophy.

The purpose of this study was to clarify changes in cough function in patients with multiple system atrophy (MSA). Seventeen probable patients with MSA were studied. Peak cough flow (PCF), respiratory function (percentage of vital capacity, percentage of forced vital capacity, and percentage of predicted forced expiratory volume in one second), respiratory muscle strength (percentage of maximal inspiratory mouth pressure and percentage of maximal expiratory mouth pressure), and maximum phonation time (MPT) were assessed. Walking ability, disease duration, possibility of air stacking, Unified MSA Rating Scale (UMSARS), and Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III were also assessed. Data were separately analyzed for ambulatory and non-ambulatory groups categorized by Functional Ambulation Categories. PCF, respiratory function, respiratory muscle strength, and MPT were significantly lower in the non-ambulatory group than in the ambulatory group. On the other hand, no correlation between PCF and disease duration was observed. A significant number of patients in the non-ambulatory group were unable to hold their breath. The UMSARS and MDS-UPDRS Part III in the non-ambulatory group were significantly higher than in the ambulatory group. It was concluded that ambulatory dysfunction is associated with the decline of cough function and respiratory-related function in patients with MSA.

Prestroke VO2max by the Jurca prediction index as a predictor of functional outcomes in stroke patients.

BACKGROUND: Prestroke cardiopulmonary fitness (CPF) levels can affect post-stroke respiratory function and functional status, including gait and activities of daily living (ADL). OBJECTIVES: To investigate the prestroke CPF level measured by the Jurca prediction index as a predictor of functional outcomes after stroke and to evaluate the association between estimated prestroke CPF and respiratory function after stroke. METHODS: This was a prospective observational study involving 71 inpatients with first-time subacute stroke between June 2017 and July 2019. The prestroke VO2max was assessed using the Jurca prediction index, which was calculated from age, sex, resting heart rate, body mass index, and physical activity level. Linear regression analysis was performed to determine the relationship between the Jurca prediction index, functional outcomes, pulmonary functions, and cough strength variables. RESULTS: The estimated prestroke VO2max was significantly associated with the post-stroke Berg Balance Scale (ß=1.199, P<0.001), Trunk Impairment Scale (ß=0.308, P=0.006), and Functional Independence Measure score (ß=1.102, P=0.004) at admission, and these relationships remained significant at the follow-up evaluation after 1 month of conventional rehabilitation (P<0.001). Among the respiratory function variables, only peak cough flow (PCF) (ß=0.696, P=0.037) was significantly associated with the estimated prestroke VO2max. CONCLUSIONS: Prestroke CPF likely affects the stability of core muscles that are related to PCF and the functional status, including balance function and ADL after stroke. Regular exercise to increase the CPF level should be encouraged in patients with risk factors for stroke, not only for primary prevention but also for functional improvement after stroke.

From bedside to bench - In vivo and in vitro evaluation of mechanically assisted cough treatment in a patient with bulbar Amyotrophic Lateral Sclerosis.

When the ability to cough is impaired, secretion clearance may be assisted and augmented by Mechanical Insufflation-Exsufflation (MI-E) treatment. In patients with Amyotrophic Lateral Sclerosis, the efficacy of MI-E may be hampered by counterproductive upper airway responses. Careful adjustment of MI-E settings can be beneficial. During the disease progression, a 41-year-old woman with bulbar Amyotrophic Lateral Sclerosis experienced that treatment with MI-E was exhausting and inefficient. Despite adjustments of settings, all treatment led to retching. A change of MI-E device led to more effective treatment. A bench test revealed variations in flow and pressure waveforms in the two devices. When MI-E treatment fails, differences in equipment delivery need to be considered in addition to the adjustment of MI-E settings.

Severely disabled multiple sclerosis patients can achieve the performance of healthy subjects after expiratory muscle strength training.

BACKGROUND: The efficacy of expiratory muscle strength training (EMST) in patients with multiple sclerosis (MS) is controversial. The current study's primary objective was to test the effects of a progressive and intensive 12 week home based EMST program on expiratory muscle strength and voluntary cough strength. The secondary objective was to determine the retention of EMST benefits. METHODS: Thirty-five severely disabled MS patients (relapsing-remitting MS, n = 15; primary progressive MS, n = 5; secondary progressive MS, n = 15) with Expanded Disability Status Scale (EDSS) 5.0 - 7.0 were included in the study. Within 36 weeks, patients completed 12 weeks of a non-training period, 12 weeks of EMST and 12 weeks of a detraining period. Maximal expiratory pressure (PEmax) and voluntary peak cough flow (vPCF) were assessed 4 times: at week 0 (baseline), week 12 (pre-training), week 24 (post-training), and week 36 (post-detraining). MS patients included in the study were compared to age- and sex-matched healthy subjects. In the healthy controls, the PEmax and vPCF were assessed once to obtain normative data. RESULTS: Twenty-six patients completed the training period (mean age 52.7 ± 10.2, EDSS 5.9 ± 0.6) and were compared to 26 sex- and age-matched healthy subjects (mean age 53.5 ± 5.8). Patients with MS had a lower PEmax (p = 0.002) and vPCF (p = 0.022) at baseline than the healthy control group. In training period, the PEmax and vPCF increased (p = 0.0000; effect size: d = 0.94 and p = 0.0036; d = 0.57 respectively) in comparison with the non-training period (p = 0.0692; d = -0.36 and p = 0.5810; d = 0.11 respectively). Following the 12 weeks detraining period, the PEmax and vPCF declined but remained 16.7% and 5.5% respectively above the pre-training values. No differences were observed in the PEmax and vPCF between the MS group at the post-training and post-detraining timepoint and the healthy control group normative values. CONCLUSIONS: EMST improves expiratory muscle strength and voluntary cough strength in severely disabled MS patients.

Respiratory measurements and airway clearance device prescription over one year in amyotrophic lateral sclerosis.

Objective: The rates of decline in respiratory measurements, including Peak Cough Flow (PCF) have not been established in Amyotrophic Lateral Sclerosis (ALS). Additionally, optimal prescription of cough adjuncts which aim to increase cough strength are unknown. The primary aim of this study was to quantify declines in respiratory function in ALS using PCF, Sniff Nasal Inspiratory Pressure (SNIP) and Slow Vital Capacity (SVC). Secondary aims were to measure respiratory morbidity, audit the characteristics of those prescribed cough adjuncts, and compare outcomes between treated and untreated cohorts. Methods: A prospective, longitudinal, observational, cohort study evaluated respiratory measures, morbidity, and physical function in ALS patients at three monthly intervals, over one year. Patient and disease characteristics of those prescribed cough adjuncts were profiled at the time of device prescription. Results: one hundred and eight participants with mean age 62.1 ± 11.5 years participated. PCF declined rapidly at a rate of 124.8L/min/year (p < 0.001). SNIP, SVC (%predicted), and ALSFRS-R also declined significantly at rates of 18.72cmH2O, 17.49%, and 9.62 units per year respectively (p < 0.001). Thirty-two (29.6%) patients reported 56 incidences of chest infection and 21 died. Patients prescribed a cough adjunct (44.4%) had significantly lower average PCF, SNIP, SVC percent predicted, and ALSFRS-R (p < 0.001). Conclusions: This study identified a rapid rate of decline in PCF, a similar decline in SNIP, and slower declines in SVC and ALSFRS-R. Cough adjunct prescription was triggered by declining respiratory measures and recommended PCF thresholds, but also by respiratory symptoms. Chest infections were common in patients regardless of cough adjunct prescription and should be closely monitored.

The utility of using peak expiratory flow and forced vital capacity to predict poor expiratory cough flow in children with neuromuscular disorders.

BACKGROUND: Approximately one in every 1200 South Africans is affected by a neuromuscular disease (NMD). Weak respiratory muscles and ineffective cough contribute to the development of respiratory morbidity and mortality. Early identification of individuals at risk of respiratory complications, through peak expiratory cough flow (PCF) measurement, may improve patient outcomes through timely initiation of cough augmentation therapy. OBJECTIVES: The aim of this study was to investigate the relationship between peak expiratory flow (PEF), forced vital capacity (FVC) and PCF in South African children with neuromuscular disorders. METHODS: A retrospective descriptive study of routinely collected data was conducted. RESULTS: Forty-one participants (aged 11.5 ± 3.6 years; 75.6% male) were included. There was a strong linear correlation between PCF and PEF (R = 0.78; p = 0.0001) and between PCF and FVC (R = 0.61; p = 0.0001). There was good agreement between PCF and PEF, with intraclass correlation coefficient of 0.8 (95% confidence interval, 0.7-0.9; p < 0.0001). Peak expiratory flow < 160 L.min-1 and FVC < 1.2 L were significantly predictive of PCF < 160 L.min-1 (suggestive of cough ineffectiveness), whilst PEF < 250 L.min-1 was predictive of PCF < 270 L.min-1, the level at which cough assistance is usually implemented. CONCLUSION: PEF and FVC may be surrogate measures of cough effectiveness in children with neuromuscular disorders. CLINICAL IMPLICATIONS: PEF and FVC may be considered for clinical use as screening tools to identify patients at risk for pulmonary morbidity related to ineffective cough.