Investigating the risk of reintubation by cough force assessment using cough peak expiratory flow: a single-center observational pilot study.

BACKGROUND: No objective indicator exists for evaluating cough strength during extubation of tracheally intubated patients. This study aimed to determine whether cough peak expiratory flow (CPEF) can predict the risk of reintubation due to decreased cough strength. METHODS: This was a retrospective cohort study of patients who were admitted to our Emergency Intensive Care Unit between September 1, 2020 and August 31, 2021 and were under artificial ventilation management for ≥ 24 h. The patients were divided into two groups: successful extubation and reintubation groups, and the relationship between CPEF immediately before extubation and reintubation was investigated. RESULTS: Seventy-six patients were analyzed. In the univariate analysis, CPEF was significantly different between the successful extubation (90.7 ± 25.9 L/min) and reintubation (57.2 ± 6.4 L/min) groups (p < 0.001). In the multivariate analysis with age and duration of artificial ventilation as covariates, CPEF was significantly lower in the reintubation group (p < 0.01). The cutoff value of CPEF for reintubation according to the receiver operating characteristic curve was 60 L/min (area under the curve, 0.897; sensitivity, 78.5%; specificity, 90.9%; p < 0.01). CONCLUSION: CPEF in tracheally intubated patients may be a useful indicator for predicting the risk of reintubation associated with decreased cough strength. The cutoff CPEF value for reintubation due to decreased cough strength was 60 L/min.

Long-term trajectories of peak expiratory flow rate in older men and women show linear decline mainly determined by baseline levels.

BACKGROUND: Peak expiratory flow rate (PEFR) predicts mortality and other negative health outcomes. However, little evidence exists on how PEFR changes with ageing and how trajectories of change differ among older people. AIMS: To identify trajectories of PEFR in older men and women, and to study characteristics associated with these trajectories. METHODS: Data from the Longitudinal Aging Study Amsterdam were used, an ongoing cohort study in a representative sample of Dutch older men and women. PEFR was assessed using the Mini-Wright peak flow meter across a 13-year follow-up in 991 men and 1107 women. Trajectories were analyzed using Latent Class Growth Analysis. RESULTS: Mean age was 72.5 (SD 8.4) in men and 72.4 (SD 8.4) in women. In men, three declining trajectories were identified, i.e. high, intermediate and low, with prevalences of 30%, 46% and 24%, respectively. In women, two declining trajectories were identified, i.e. high and low, with prevalences of 62 and 38%. All trajectories showed linear decline and differed mostly with regard to their intercept. Significant differences between trajectories with regard to baseline demographic, health and lifestyle characteristics were observed, e.g., men and women in the low PEFR trajectory were older, had more chronic diseases, and were more often smoker. DISCUSSION AND CONCLUSIONS: Trajectories in both men and women differ mainly in baseline level of PEFR and not in rate of decline over time. Therefore, one PEFR measurement might be sufficient to give an indication of the trajectory that an older adult is likely to follow.

The relationship between changes in peak expiratory flow and asthma exacerbations in asthmatic children.

BACKGROUND: Asthma is one of the most common chronic airway diseases in children. Preventing asthma exacerbation is one of the objectives of all asthma action plans. In patients with poor perception, it is difficult to identify acute asthma exacerbations by clinical asthma score, asthma control test or asthma control questionnaire. The aim of this study is to analyze whether children with asthma have changes in peak expiratory flow(PEF)before an acute asthma exacerbation and to evaluate the relationship between PEF and asthma exacerbation. METHODS: Basic information (including sex, age, atopy, etc.) and clinical information of asthmatic children who registered in the Electronic China Children's Asthma Action Plan (e-CCAAP) from 1 September 2017 to 31 August 2021 were collected. Subjects with 14 consecutive days of PEF measurements were eligible. Subjects in this study were divided into an exacerbation group and a control group. We analyzed the relationship between changes in PEF% pred and the presence of asthma symptoms. RESULT: A total of 194 children with asthma who met the inclusion criteria were included, including 144 males (74.2%) and 50 females (25.8%), with a male-to-female ratio of 2.88:1. The mean age of the subjects was 9.51 ± 2.5 years. There were no significant differences in sex, age, allergy history or baseline PEF between the two groups. In children with and without a history of allergy, there was no significant difference between the variation in PEF at 14 days. Patients who only had a reduced in PEF but no symptoms of asthma exacerbation had the greatest reduction in PEF compared to the other groups. The most common cause of acute exacerbations of asthma is upper respiratory tract infection. Among the causes of acute exacerbations of asthma, the variation in PEF caused by air pollution was significantly higher than that of other causes (P < 0.05). In acute exacerbations, the decrease in PEF was significantly greater in the exacerbation group than in the control group. In children with asthma symptoms, there was a decrease in PEF approximately 1.34 days before the onset of symptoms. CONCLUSION: Children with asthma show a decrease in PEF 1.34 days before the onset of asthma symptoms. We recommend that asthmatic children who show a decrease in PEF should step-up asthma therapy. The most common cause of acute exacerbations of asthma was upper respiratory tract infections, and the variation in PEF caused by air pollution was significantly higher than that caused by other factors.

Cough flows as a criterion for decannulation of autonomously breathing patients with tracheostomy tubes.

BACKGROUND: Adequate cough or exsufflation flow can indicate an option for safe tracheostomy decannulation to noninvasive management. Cough peak flow via the upper airways with the tube capped is an outcome predictor for decannulation readiness in patients with neuromuscular impairment. However, this threshold value is typically measured with tracheotomy tube removed, which is not acceptable culturally in China. The aim of this study was to assess the feasibility and safety of using cough flow measured with tracheostomy tube and speaking valve (CFSV) > 100 L/min as a cutoff value for decannulation. STUDY DESIGN: Prospective observational study conducted between January 2019 and September 2022 in a tertiary rehabilitation hospital. METHODS: Patients with prolonged tracheostomy tube placement were referred for screening. Each patient was assessed using a standardized tracheostomy decannulation protocol, in which CFSV greater than 100 L/min indicated that the patients' cough ability was sufficient for decannulation. Patients whose CFSV matched the threshold value and other protocol criteria were decannulated, and the reintubation and mortality rates were followed-up for 6 months. RESULTS: A total of 218 patients were screened and 193 patients were included. A total of 105 patients underwent decannulation, 103 patients were decannulated successfully, and 2 patients decannulated failure, required reinsertion of the tracheostomy tube within 48 h (failure rate 1.9%). Three patients required reinsertion or translaryngeal intubation within 6 months. CONCLUSIONS: CFSV greater than 100 L/min could be a reliable threshold value for successful decannulation in patients with various primary diseases with a tracheostomy tube. TRIAL REGISTRATION: This observational study was not registered online.

The anthropometric determinants of peak expiratory flow rate among children in Dar Es Salaam, Tanzania.

BACKGROUND: Peak expiratory flow rate (PEFR) is an important tool for assessing lung function, which can be affected by environmental and physical factors such as altitude, nutrition, genetics, age, height, and weight. Conducting a study to assess the correlation between peak expiratory flow rate and anthropometric measurements in Tanzanian schoolchildren is crucial to derive a population-specific prediction formula and further simplify respiratory health assessment. METHODS: This cross-sectional study was conducted in a single center private primary and secondary school in Dar es Salaam, Tanzania using data from an asthma screening camp. Variables of interest were height, weight, Body Mass Index (BMI) and PEFR. Independent t-test was performed to identify any differences in mean flow rate values between different ethnicities and genders. Correlation coefficients (r) were used to observe the relationship between PEFR and anthropometric measurements. A prediction equation by gender was generated using linear regression analysis. Statistical significance was set at the 5% level. All statistical data was analyzed using SPSS version 25.0. RESULTS: The study involved 260 participants with a mean age of 9.5 years. Males were 51.2% and 65% of participants were of Asian ethnicity. PEFR was not observed to differ across the different ethnic groups and genders. Height was found to have the strongest correlation coefficient of 0.745, while BMI had the weakest correlation coefficient of 0.366. The strongest correlation was found with height for females (r = 0.787), while the weakest was with body mass index for boys (r = 0.203). The derived prediction equation for males was PEFR = 279.169 (Height of Student in meters) -134.12, while the predictive equation for females was PEFR = 318.32 (Height of Student in meters) -195.69. CONCLUSION: This study found a strong correlation between PEFR and anthropometric characteristics in school children from Dar es Salaam, Tanzania. A prediction equation by gender for PEFR was developed based on anthropometric characteristics. This equation may be applied in population-based studies or situations where peak flow meters are not readily available. Further research is needed to explore how well this prediction formula performs in other Tanzanian settings and to determine other factors that may affect lung function in this population.

Applicable predictive factors extracted from peak flow trajectory for the prediction of asthma exacerbation.

BACKGROUND: Real-time asthma exacerbation prediction and acute asthma attack detection are essential for patients with severe asthma. Peak expiratory flow (PEF) exhibits a potential for use in long-term asthma self-monitoring. However, the method for processing PEF calculations remains to be clarified. OBJECTIVE: To develop clinically applicable novel exacerbation predictors calculated using PEF records. METHODS: Previously proposed exacerbation predictors, including the slope of PEF, percentage predicted PEF, percentage best PEF, the highest PEF over the lowest PEF within specific periods, and PEF coefficient of variation, in addition to a novel indicator delta PEF moving average (ΔMA), defined as the difference between 14-day and 3-day average PEF values, along with moving average (MA) adjusted for PEF reference (%ΔMA), were verified using the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma data of 127 patients with severe asthma from whom 73,503 PEF observations were obtained. Receiver operating characteristic curves for all predictors were drawn, and the corresponding areas under the curve (AUCs) were computed. Regression analysis for MA and percentage MA were conducted. RESULTS: The most outstanding performance was shown by ΔMA and %ΔMA, with AUC values of 0.659 and 0.665 in the univariate model, respectively. When multivariate models were incorporated with random intercepts for individual participants, the AUC for ΔMA and %ΔMA increased to 0.907 and 0.919, respectively. CONCLUSION: The MA and percentage MA are valuable indicators that should be considered when deriving predictors from the PEF trajectory for monitoring exacerbations in patients with severe asthma. TRIAL REGISTRATION: The Hokkaido-based Investigative Cohort Analysis for Refractory Asthma was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN ID: 000003254). https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003917.

Sound-based cough peak flow estimation in patients with neuromuscular disorders.

INTRODUCTION/AIMS: Cough impairment is common in individuals with neuromuscular disorders and is associated with respiratory infections and shorter survival. Cough strength is assessed by measuring cough peak flow (CPF) using a flow meter, but this method requires a complex device setup and trained staff. The aim of the study is to evaluate the reliability of a smartphone app to estimate CPF based on cough sounds in a cohort of individuals with neuromuscular disorders. METHODS: Individuals with neuromuscular disorders underwent CPF measurement with a flow meter and a smartphone app. A CPF <270 L/min was considered abnormal. RESULTS: Of the 50 patients studied, 26 had amyotrophic lateral sclerosis (52%), 15 had hereditary myopathies (30%), and 9 had myasthenia gravis (18%). The intraclass correlation coefficient (ICC) between the CPF measured with a flow meter and CPF estimated with cough sounds was 0.774 (p < .001) even if the patients had orofacial weakness (ICC = 0.806, p < .001). The smartphone app had 94.4% sensitivity and 100% specificity to detect patients with CPF of less than 270 L/min. DISCUSSION: Our findings suggest that sounds measured with a smartphone app provide a reliable estimate of CPF in patients with neuromuscular disorders, even in the presence of with orofacial weakness. This may be a convenient way to monitor respiratory involvement in patients with neuromuscular disorders, but larger studies of more diverse patient cohorts are needed.

Relation of changes in PEF and FEV1 in exercise challenge in children.

Decrease in forced expiratory volume in one second (FEV1 ) of 10% or 15% in exercise challenge test is considered diagnostic for asthma, but a decrease of 15% in peak expiratory flow (PEF) is recommended as an alternative. Our aim was to assess the accuracy of different PEF cut-off points in comparison to FEV1 . We retrospectively studied 326 free running exercise challenge tests with spirometry in children 6-16 years old. FEV1 and PEF were measured before and 2, 5, 10 and 15 min after exercise. Receiver operating characteristics (ROC) analysis, sensitivity, specificity, positive and negative predictive values (PPV and NPV) and Ï°-coefficient were used to analyse how decrease in PEF predicts decrease of 10% or 15% in FEV1 . In the ROC analysis, areas under the curve were 0.851 (p < 0.001) and 0.921 (p < 0.001) for PEF decrease to predict a 10% and 15% decrease in FEV1 , respectively. The agreement between changes in PEF and FEV1 varied from slight to substantial (Ï° values of 0.199-0.680) depending on the cut-points. Lower cut-off for decrease in PEF had higher sensitivity and NPV, while higher cut-off values had better specificity and PPV. Decrease of 20% and 25% in PEF seemed to be the best cut-offs for detecting 10% and 15% decrease in FEV1 , respectively. Still, a fifth of the positive findings based on PEF were false. Change in PEF is not a precise predictor of change in FEV1 in exercise test. The currently recommended cut-point of 15% decrease in PEF seems to be too low and leads to high false positive rate.

Physical activity improves health-related quality of life, 6MWT, and VO2 peak before and during COVID-19 in patients with heart failure: A meta-analysis / La actividad física mejora la calidad de vida relacionada con la salud, el 6MWT y el pico de VO2 antes y durante la COVID-19 en pacientes con insuficiencia cardíaca: un metanálisis

Objective To compare the effects of physical activity on improving health-related quality of life (HRQOL), six minutes walking test (6MWT), and oxygen consumption (VO2) peak before and during Coronavirus disease (COVID-19) in patients with heart failure. Methods Following PRISMA guidelines, we searched for relevant articles from five databases, including Embase, MEDLINE, CINAHL, PEDro, Cochrane, and additional resources. Study quality was assessed using Joanna Briggs Institution (JBI). RevMan 5.3 software was used to perform the meta-analysis. Result Fifteen randomized controlled trial studies met the criteria. Analysis of the subgroup before COVID-19 showed that PA had a significant effect on HRQOL, as measured by MLHFQ (SDM: −0.27, 95% CI: −0.47 to −0.07, n=590), KCCQ (SDM: 2.10, 95% CI: 0.74 to 3.46, n=53), 6MWT (SMD: 1.63, 95% CI: 0.80 to 2.46, n=284), and VO2 peak (SMD: 0.97, 95% CI: 0.00 to 1.93, n=106). Analysis of the subgroup during COVID-19 showed that PA resulted in a significant effect on HRQOL, MLHFQ (SDM: −0.62, 95% CI: −1.32 to 0.09, n=221), KCCQ (SDM: 0.33, 95% CI: 0.15 to 0.50, n=486), 6MWT (SMD: 0.47, 95% CI: 0.22 to 0.73, n=493), and VO2 peak (SMD: 0.35, 95% CI: 0.10 to 0.60, n=325). Conclusion The PA could increase HRQOL, 6MWT, and VO2 peak before and during COVID-19, and therefore should be considered as part of daily activities for patients with HF (AU)

Objetivo Comparar los efectos de la actividad física en la mejora de la calidad de vida relacionada con la salud (CVRS), el 6MWT y el pico de VO2 antes y durante la COVID-19 en pacientes con insuficiencia cardíaca. Métodos Siguiendo las pautas PRISMA, buscamos artículos relevantes en 5 bases de datos, incluidas Embase, MEDLINE, CINAHL, PEDro y Cochrane, así como recursos adicionales. Para evaluar la calidad del estudio se utilizó el Instituto Joanna Briggs, y el software RevMan 5.3 para realizar el metanálisis. Resultado Quince artículos de ensayos controlados aleatorizados cumplieron con los criterios. El análisis del subgrupo antes de la COVID-19 mostró que la actividad física tuvo un efecto significativo en la CVRS, según lo medido por el MLHFQ (DE: −0,27, IC 95%: −0,47 a −0,07, n=590), el KCCQ (DE: 2,10, IC 95%: 0,74 a 3,46, n=53), el 6MWT (DE: 1,63, IC 95%: 0,80 a 2,46, n=284) y el pico de VO2 (DE: 0,97, IC 95%: 0,00 a 1,93, n=106). El análisis del subgrupo durante la COVID-19 mostró que la actividad física tuvo un efecto significativo en la CVRS, el MLHFQ (DE: −0,66, IC 95%: −1,32 a 0,09, n=221), el KCCQ (DE: 0,33, IC 95%: 0,15 a 0,50, n=486), el 6MWT (DE: 0,47, IC 95%: 0,22 a 0,73, n=493) y el pico de VO2 (DE: 0,35, IC 95%: 0,10 a 0,60, n=325). Conclusión La actividad física podría aumentar la CVRS, el 6MWT y el pico de VO2 antes y durante la COVID-19, por lo que debe ser considerada como parte de las actividades diarias de los pacientes con insuficiencia cardíaca (AU)

Comparative Study on Chronic Obstructive Pulmonary Disease Screening Tools in Primary Healthcare Institutions in Beijing, China.

Background: Chronic obstructive pulmonary disease (COPD) has a high incidence rate in China, but the diagnosis rate remains insufficient. This study aimed to explore and compare COPD screening tools for primary healthcare institutions in China. Purpose: Exploring COPD Screening Tools and Their Combined Use for Primary Healthcare Institutions in China. Patients and Methods: From September 2022 to March 2023, a screening for COPD was conducted among residents aged 35 years and above in primary healthcare institutions in Beijing, China. The screening involved the use of the CAPTURE scale, COPD-SQ scale, and peak expiratory flow rate test. Any positive results from these screening tests were followed by further pulmonary function testing to confirm the diagnosis. Sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic (ROC) curves were calculated for each screening tool alone and in combination. Results: A total of 986 individuals completed the screening tests. The positive rates for the CAPTURE scale, COPD-SQ scale, and peak flow meter screening were 41.78%, 29.11%, and 52.03%, respectively. Of the participants, 166 (24.09%) underwent pulmonary function tests, with an average age of 61.69±13.68 years. The peak flow meter screening showed the highest sensitivity (83.78%) when used alone, while the COPD-SQ scale exhibited the best specificity (59.69%), positive predictive value (31.58%), and negative predictive value (58.56%). Significant differences (P<0.05) were observed between any two of the three screening tools. Among the combinations, the peak flow meter screening + COPD-SQ scale showed the highest accuracy, with a Youden index of 0.277 and an AUC of 0.638. Conclusion: There is variation in the accuracy of existing screening tools for COPD when used alone. For primary healthcare institutions, the optimal COPD screening tool is the combination of peak flow meter screening and the COPD-SQ questionnaire. If limited by screening equipment conditions, the COPD-SQ questionnaire can be used alone for screening.

El pico flujo espiratorio y la cuenta máxima son marcadores del compromiso respiratorio en la miastenia gravis / Peak expiratory flow and the single-breath counting test as markers of respiratory function in patients with myasthenia gravis

Introducción: La miastenia gravis (MG) es una enfermedad autoinmune mediada por anticuerpos. El cuadro clínico se caracteriza por debilidad muscular fluctuante y fatigable, con frecuente afectación de músculos fonodeglutorios y respiratorios. Dada la severidad que implica el compromiso respiratorio en la MG, su evaluación rutinaria es esencial.Nuestro objetivo fue identificar un marcador semiológico útil en la pesquisa del compromiso respiratorio en pacientes con MG.Métodos: Se realizó un trabajo observacional en pacientes con diagnóstico de MG. Los pacientes fueron evaluados con test de cuenta máxima, pico flujo espiratorio (PEF), cuestionario de disnea modificado (mMRC) y valoración de fuerza del cuello. Los resultados de estos parámetros fueron correlacionados con la medición de CVF (capacidad vital forzada) y presiones bucales estáticas máximas (PiMáx y PeMáx). Resultados:Cuarenta y cinco pacientes con MG fueron incluidos, dos pacientes tenían MGFA grado I, 35 grado II, siete grado III y uno grado IV al momento de la evaluación. Se halló una correlación positiva entre el test de cuenta máxima y la CVF (r = 0,57, p = 0,000), y entre el PEF y la CVF (r = 0,76, p = 0,000). El grado de disnea, según el mMRC, mostró una correlación negativa con la CVF (r =-0,31 p = 0,03). A su vez, el PEF correlacionó con la PeMáx de forma positiva, estadísticamente significativa (r = 0,51, p = 0,002).Conclusiones: El PEF, el test de cuenta máxima y el mMRC fueron útiles para evaluar la función respiratoria en pacientes con MG.(AU)

Introduction: Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratorymuscles. Considering the severity of respiratory involvement in MG, routine evaluation ofrespiratory function is essential.The aim of this study was to identify a useful clinical marker of respiratory involvement inpatients with MG. Methods: We performed an observational study of patients with MG. All cases were evaluatedwith the single-breath counting test, peak expiratory flow (PEF), a modified Medical ResearchCouncil dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), andmaximal expiratory pressure (MEP). Results: The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified asgrade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were foundbetween single-breath counting test scores and FVC values (r = 0.57, p = .000), and betweenPEF and FVC values (r = 0.76, p = .000). Severity of dyspnoea according to the mMRC scaleshowed a negative correlation with FVC values (r = -0.31, p = .03). PEF also showed a significantcorrelation with MEP (r = 0.51, p = .002). Conclusions: PEF, the single-breath counting test, and the mMRC scale are useful measures forevaluating respiratory function in patients with MG.(AU)

Cough sound-based estimation of vital capacity via cough peak flow using artificial neural network analysis.

This study presents a novel approach for estimating vital capacity using cough sounds and proposes a neural network-based model that utilizes the reference vital capacity computed using the lambda-mu-sigma method, a conventional approach, and the cough peak flow computed based on the cough sound pressure level as inputs. Additionally, a simplified cough sound input model is developed, with the cough sound pressure level used directly as the input instead of the computed cough peak flow. A total of 56 samples of cough sounds and vital capacities were collected from 31 young and 25 elderly participants. Model performance was evaluated using squared errors, and statistical tests including the Friedman and Holm tests were conducted to compare the squared errors of the different models. The proposed model achieved a significantly smaller squared error (0.052 L2, p < 0.001) than the other models. Subsequently, the proposed model and the cough sound-based estimation model were used to detect whether a participant's vital capacity was lower than the typical lower limit. The proposed model demonstrated a significantly higher area under the receiver operating characteristic curve (0.831, p < 0.001) than the other models. These results highlight the effectiveness of the proposed model for screening decreased vital capacity.

Screening for impaired pulmonary function using peak expiratory flow: Performance of different interpretation strategies.

BACKGROUND: Spirometry is the gold standard for diagnosis of impaired pulmonary function, but is often unavailable in resource-constrained settings. Some authors have suggested using peak expiratory flow (PEF) to screen for impaired pulmonary function when spirometry is unavailable, but with no consensus on how to define abnormally low PEF. Strategies have included cutoffs based on absolute value of PEF, PEF in percent predicted, PEF Z-score, PEF × height-2, and gender-specific cutoffs of absolute PEF. The objective of this paper is to determine the PEF interpretation strategy with the highest predictive ability for low pulmonary function, with spirometry as the gold standard. METHODS: We analyzed data on individuals aged 40-79 years in the United States National Health and Nutrition Examination Survey 2007-2012. 6,144 individuals fulfilled inclusion criteria for the main analysis. For each PEF interpretation strategy, we calculated the area under the receiver operating curve (AUC) for the detection of low pulmonary function (defined by FEV1 Z-score < -1.645, < -2, < -2.5 or < -3). RESULTS: The AUC was substantially and statistically significantly higher for PEF in percent predicted and PEF Z-score than for absolute value and PEF × height-2, including after stratification by gender. There was no difference in AUC between PEF in percent predicted and PEF Z-score. CONCLUSION: If using PEF to screen adults aged 40 years or older for impaired pulmonary function defined by low FEV1 Z-score, basing cutoffs on PEF in percent predicted or PEF Z-score may result in improved predictive ability. As percent predicted is a mathematically simpler term than Z-score, it may be preferable to use cutoffs based on PEF in percent predicted.

Comparison of Four Mechanical Insufflation-Exsufflation Devices: Effect of Simulated Airway Collapse on Cough Peak Flow.

BACKGROUND: Mechanical insufflation-exsufflation (MI-E) devices are used to improve airway clearance in individuals with acute respiratory failure. Some MI-E devices measure cough peak flow (CPF) during MI-E to optimize pressure adjustments. The aim was to compare CPF and effective cough volume (ECV: volume expired/coughed > 3 L/s) measurements between 4 MI-E devices under simulated conditions of stable versus collapsed airway. METHODS: Four MI-E devices were tested on the bench. Each device was connected via a standard circuit to a collapsible tube placed in an airtight chamber that was attached to a lung model with adjustable compliance and resistance. Pressure was measured upstream and downstream the collapsing tube; air flow was measured between the chamber and the lung model. Each device was tested in 2 conditions: collapse condition (0 cm H2O) and no-collapse condition (-70 cm H2O). For each condition, 6 combinations of inspiratory/expiratory pressures were applied. CPF was measured at the "mouth level" by the device built-in flow meter and at the "tracheal level" by a dedicated pneumotachograph. Comparisons were performed with non-parametric tests. RESULTS: CPF values measured at the tracheal level and ECV values differed between devices for each inspiratory/expiratory pressure in the collapse and no-collapse conditions (P < .001). CPF values were significantly lower at the tracheal level in the collapse as compared with the no-collapse condition (P < .001 for each device), whereas they were higher at the mouth level (P < .05) for 3 of the 4 devices. CONCLUSIONS: CPF values differed significantly across MI-E devices, highlighting limitation(s) of using only CPF values to determine cough effectiveness. In simulated of airway collapse, CPF increased at the mouth, whereas it decreased at the tracheal level.

Does peak expiratory flow moderate trajectories of cognitive function among individuals with lung diseases? A longitudinal analysis of the National Health and Aging Trends Study.

INTRODUCTION: Impaired cognitive function can co-exist in chronic respiratory diseases. However, it is not clear if peak expiratory flow (PEF) impacts changes in cognitive function. Our objective was to explore whether peak expiratory flow moderates trajectories of memory, visuospatial abilities, and executive function in individuals with chronic respiratory diseases. METHODS: This was an analysis of individuals with lung diseases from the National Health and Aging Trends Study. Multivariable-adjusted generalized linear mixed models were used to estimate trajectories of immediate and delayed recall, and clock drawing over a 10-year follow-up. The interaction between PEF and time were plotted using sex-specific values for peak expiratory flow at 10th, 50th and 90th percentiles. RESULTS: In females, interactions of time-by-PEF were found for both immediate (n = 489, t = 2.73, p<0.01) and delayed recall (n = 489, t = 3.38, p<0.01). Females in the 10th vs. 90th percentile of PEF declined in immediate recall at 0.14 vs. 0.065 words/year, and 0.17 vs. 0.032 words/year for delayed recall. Among males, recall declined linearly over 10 years (immediate recall: n = 296, t = -3.08, p < 0.01; delayed recall: n = 292, t = -2.46, p = 0.02), with no interaction with PEF. There were no time-by-PEF interactions nor declines over time in clock drawing scores in both sexes (females: n = 484, t = 0.25, p = 0.81; males: n = 291, t = -0.61, p = 0.55). CONCLUSION: Females with the lowest PEF values experienced the greatest rates of decline in immediate and delayed recall over 10 years of follow-up, whereas males experienced similar declines in memory outcomes across all levels of PEF. Clock drawing scores remained stable over 10 years in both sexes.

Feasibility and acceptability of home monitoring with portable spirometry in young adults with asthma.

OBJECTIVE: Self-monitoring asthma control is a key component of asthma management. Few studies have reported usability and acceptability of portable spirometry among young adults with asthma. Portable spirometry offers a practical solution to monitoring airway narrowing at home. The purpose of this paper was to determine if self-administered spirometry is feasible and acceptable in young adults with asthma and whether regular monitoring resulted in improved airway function as measured by forced expiratory volume in one second (FEV1). METHODS: Sixty-seven young adults (18-26 years) with self-reported asthma participated in a clinical trial during wildfire season which measured FEV1 as an outcome measure. Data was collected at baseline, week 4, and week 8 using a portable spirometer linked to a smartphone application. A subset of intervention participants completed spirometry twice daily. Acceptability of self-administered spirometry was evaluated after the trial among participants that volunteered to submit a survey and be interviewed. RESULTS: At baseline, all 67 participants (100.0%) completed their scheduled spirometry readings which declined to 94.0% (n = 63) at week 4 and 86.6% (n = 58) at week 8. Daily readings were completed 83.2% of the time in the mornings and 84.3% of the time in the evenings. Mean FEV1 values were lower than predicted values, but above the lower limit of expected. FEV1 remained steady throughout the study period. Over two-thirds of participants used the notes feature in the application and described symptoms, asthma triggers, mitigating actions and test-taking issues. CONCLUSIONS: Young adults in our sample were highly compliant with regular, self-administered spirometry.

[Can cough peak flow be used to assess cough capacity in severe obstructive respiratory diseases?] / ¿Se puede utilizar la determinación del pico flujo de tos para valorar la capacidad tusígena en enfermedades respiratorias obstructivas graves?

INTRODUCTION: Cough capacity is assessed by measuring cough peak flow (CPF). However, this assessment could be altered by obstructive airway diseases. The aim was to assess measurement of cough capacity by CPF in patients with chronic obstructive pulmonary disease (COPD), as well as correlations with pulmonary, respiratory muscle, and oropharyngeal function. METHODS: Patients with COPD, and with neuromuscular disease, were selected as well as healthy subjects who had undergone respiratory muscle strength measurement in a healthcare setting. From this population, respiratory function values and lung and oropharyngeal muscle function were analysed. A subgroup of COPD patients underwent a videofluoroscopic swallow study. RESULTS: Three hundred and seven subjects were included (59.3% COPD, 38.4% neuromuscular diseases, and 2.3% healthy). CPF was found to be statistically significantly decreased in the COPD group compared to both the healthy and neuromuscular disease groups. Of the COPD patients, 70% had a pathological decrease in CPF. There was only a direct correlation between CPF with the degree of bronchial obstruction and expiratory muscle strength. No alteration of inspiratory or oropharyngeal muscle function was found. CONCLUSIONS: The use of CPF in COPD patients does not reflect cough capacity as it is influenced by the degree of bronchial obstruction. Therefore, new diagnostic tests to measure cough capacity should be considered, especially in patients with coexisting neuromuscular diseases and severe bronchial obstructive disease.

Can the Remote Use of a Peak Flow Meter Predict Severity of Subglottic Stenosis and Surgical Timing?

OBJECTIVE: We aimed to assess the relationship between patient-performed and patient-reported peak flow meter (PFM) measurements with pulmonary function testing (PFT) and Dyspnea Index (DI) scores as a tool for monitoring Subglottic stenosis (SGS) disease progression remotely. METHODS: Thirty-five SGS patients were prospectively enrolled. Patients were given PFMs to report serial measurements from home. DI scores and PFT were recorded at serial clinic visits. Data were analyzed to determine the correlation between PFM measurements and PFT data. Pre-operative and post-operative PFM measurements, PFT, and DI scores were analyzed for patients who underwent operative intervention. Receiver operating characteristic (ROC) curves were created for PFM measurements, PFT data, and DI scores to predict the likelihood of surgery. RESULTS: PFM measurements had a "strong" correlation with the peak expiratory flow rate (PEFR), r = 0.78. Means of PEFR, PIFR, EDI, PFM measurements, and DI scores all significantly improved after the operative intervention (p ≤ 0.05). The area under the curve for ROC curves for DI scores, PFM measurements, and EDI were highest in our cohort with values of 0.896, 0.823, and 0.806, respectively. CONCLUSION: In our SGS cohort, PFM measurements correlate strongly with PEFR measurements. PFM measurements can adequately demonstrate disease progression and predict the need for surgery in this patient population. Together, DI scores and PFM measurements may be a useful tool to remotely follow patients with SGS and inform timing of in-person assessments. LEVEL OF EVIDENCE: 2 Laryngoscope, 133:628-633, 2023.

Performance testing for different peak expiratory flow meters.

BACKGROUND: Peak expiratory flow meters (PEFMs) have emerged as primary tools used for diagnosing and monitoring a range of respiratory diseases including asthma and chronic obstructive pulmonary disease, and the performance of these meters will thus impact disease evaluation. OBJECTIVE: The aim of this study was therefore to assess the technical performance of mechanical and electronic PEFMs commonly used in clinical practice. METHODS: The accuracy, repeatability, airflow resistance, frequency response, and linearity of five electronic and seven mechanical PEFMs were measured using a standard flow/volume simulator in accordance with nine A-waveforms and three B-waveforms defined in ISO 23747:2015 issued by the International Standards Organization (ISO). RESULTS: The accuracy, repeatability, linearity, airflow resistance, and frequency response pass rates for these 12 different PEFM brands were 41.67%, 75.00%, 50.00%, 75.00%, and 25.00%, respectively. Just 16.67% (2/12) of the tested PEFMs met all evaluated criteria, whereas the remaining PEFMs partially met these criteria. There were no significant differences between the two tested PEFM types in the low flow rate waveform test (P> 0.05), although there were significant differences in the medium and high flow rate waveform test (P< 0.05). In addition, the overall PEFMs test had poor accuracy and good repeatability, although most of the repeatability errors occurred in the BTPS state. CONCLUSION: PEFMs commonly used in clinical settings exhibit variable technical performance, and relevant departments need to strengthen PEFM quality control and management in China.