The physiology of cough

An Accelerometer-Based Wearable Patch for Robust Respiratory Rate and Wheeze Detection Using Deep Learning

Wheezing is a critical indicator of various respiratory conditions, including asthma and chronic obstructive pulmonary disease (COPD). Current diagnosis relies on subjective lung auscultation by physicians. Enabling this capability via a low-profile, objective wearable device for remote patient monitoring (RPM) could offer pre-emptive, accurate respiratory data to patients. With this goal as our aim, we used a low-profile accelerometer-based wearable system that utilizes deep learning to objectively detect wheezing along with respiration rate using a single sensor. The miniature patch consists of a sensitive wideband MEMS accelerometer and low-noise CMOS interface electronics on a small board, which was then placed on nine conventional lung auscultation sites on the patient's chest walls to capture the pulmonary-induced vibrations (PIVs). A deep learning model was developed and compared with a deterministic time-frequency method to objectively detect wheezing in the PIV signals using data captured from 52 diverse patients with respiratory diseases. The wearable accelerometer patch, paired with the deep learning model, demonstrated high fidelity in capturing and detecting respiratory wheezes and patterns across diverse and pertinent settings. It achieved accuracy, sensitivity, and specificity of 95%, 96%, and 93%, respectively, with an AUC of 0.99 on the test set-outperforming the deterministic time-frequency approach. Furthermore, the accelerometer patch outperforms the digital stethoscopes in sound analysis while offering immunity to ambient sounds, which not only enhances data quality and performance for computational wheeze detection by a significant margin but also provides a robust sensor solution that can quantify respiration patterns simultaneously.

Limitations of the Cough Sound-Based COVID-19 Diagnosis Artificial Intelligence Model and its Future Direction: Longitudinal Observation Study

BACKGROUND

The outbreak of SARS-CoV-2 in 2019 has necessitated the rapid and accurate detection of COVID-19 to manage patients effectively and implement public health measures. Artificial intelligence (AI) models analyzing cough sounds have emerged as promising tools for large-scale screening and early identification of potential cases.

OBJECTIVE

This study aimed to investigate the efficacy of using cough sounds as a diagnostic tool for COVID-19, considering the unique acoustic features that differentiate positive and negative cases. We investigated whether an AI model trained on cough sound recordings from specific periods, especially the early stages of the COVID-19 pandemic, were applicable to the ongoing situation with persistent variants.

METHODS

We used cough sound recordings from 3 data sets (Cambridge, Coswara, and Virufy) representing different stages of the pandemic and variants. Our AI model was trained using the Cambridge data set with subsequent evaluation against all data sets. The performance was analyzed based on the area under the receiver operating curve (AUC) across different data measurement periods and COVID-19 variants.

RESULTS

The AI model demonstrated a high AUC when tested with the Cambridge data set, indicative of its initial effectiveness. However, the performance varied significantly with other data sets, particularly in detecting later variants such as Delta and Omicron, with a marked decline in AUC observed for the latter. These results highlight the challenges in maintaining the efficacy of AI models against the backdrop of an evolving virus.

CONCLUSIONS

While AI models analyzing cough sounds offer a promising noninvasive and rapid screening method for COVID-19, their effectiveness is challenged by the emergence of new virus variants. Ongoing research and adaptations in AI methodologies are crucial to address these limitations. The adaptability of AI models to evolve with the virus underscores their potential as a foundational technology for not only the current pandemic but also future outbreaks, contributing to a more agile and resilient global health infrastructure.

TBscreen: A passive cough classifier for tuberculosis screening with a controlled dataset

Recent respiratory disease screening studies suggest promising performance of cough classifiers, but potential biases in model training and dataset quality preclude robust conclusions. To examine tuberculosis (TB) cough diagnostic features, we enrolled subjects with pulmonary TB (N = 149) and controls with other respiratory illnesses (N = 46) in Nairobi. We collected a dataset with 33,000 passive coughs and 1600 forced coughs in a controlled setting with similar demographics. We trained a ResNet18-based cough classifier using images of passive cough scalogram as input and obtained a fivefold cross-validation sensitivity of 0.70 (±0.11 SD). The smartphone-based model had better performance in subjects with higher bacterial load {receiver operating characteristic-area under the curve (ROC-AUC): 0.87 [95% confidence interval (CI): 0.87 to 0.88], P < 0.001} or lung cavities [ROC-AUC: 0.89 (95% CI: 0.88 to 0.89), P < 0.001]. Overall, our data suggest that passive cough features distinguish TB from non-TB subjects and are associated with bacterial burden and disease severity.

Factors related to pre-operative cough strength in cardiac surgical patients: a cross-sectional study

BACKGROUND

Pulmonary complications often arise from ineffective coughing, yet limited research exists on the determinants of cough strength in patients undergoing cardiac surgery.

OBJECTIVES

The aim is to explore preoperative cough strength in patients scheduled for cardiac surgery and identify factors associated with diminished cough strength.

METHODS

A cross-sectional study was conducted on 330 adult patients admitted for cardiac surgery at a tertiary Grade A hospital in Jiangsu Province, China between August 2022 and February 2023. Cough strength was assessed using cough peak flow, with values below 270 L/min classified as reduced cough strength. The study adhered to the STROBE guidelines.

RESULTS

The study comprised 228 males (69.1 %) and 102 females (30.9 %), aged 23 to 81 years. Types of cardiac surgery included coronary artery bypass surgery, heart valvuloplasty, or heart valve replacement among others. The mean preoperative cough peak flow was 250.38 ± 119.71 L/min, with 60.3 % of patients exhibiting reduced cough strength. A multiple linear regression analysis identified gender, age, exercise regimen, pulmonary arterial hypertension, left ventricular ejection fraction, inspiratory capacity, and proficiency in coughing techniques as primary factors affecting cough strength.

CONCLUSIONS

Our findings indicate an association between diminished cough strength and factors such as female gender, advanced age, absence of systematic exercise, presence of pulmonary arterial hypertension, lower left ventricular ejection fraction, reduced inspiratory capacity, and inadequate mastery of coughing techniques. Healthcare staff should prioritize regular assessment of cough strength and manage the pertinent factors to enhance preoperative coughing ability.

A semi-supervised algorithm for improving the consistency of crowdsourced datasets: The COVID-19 case study on respiratory disorder classification

BACKGROUND AND OBJECTIVE

Cough audio signal classification is a potentially useful tool in screening for respiratory disorders, such as COVID-19. Since it is dangerous to collect data from patients with contagious diseases, many research teams have turned to crowdsourcing to quickly gather cough sound data. The COUGHVID dataset enlisted expert physicians to annotate and diagnose the underlying diseases present in a limited number of recordings. However, this approach suffers from potential cough mislabeling, as well as disagreement between experts.

METHODS

In this work, we use a semi-supervised learning (SSL) approach - based on audio signal processing tools and interpretable machine learning models - to improve the labeling consistency of the COUGHVID dataset for 1) COVID-19 versus healthy cough sound classification 2) distinguishing wet from dry coughs, and 3) assessing cough severity. First, we leverage SSL expert knowledge aggregation techniques to overcome the labeling inconsistencies and label sparsity in the dataset. Next, our SSL approach is used to identify a subsample of re-labeled COUGHVID audio samples that can be used to train or augment future cough classifiers.

RESULTS

The consistency of the re-labeled COVID-19 and healthy data is demonstrated in that it exhibits a high degree of inter-class feature separability: 3x higher than that of the user-labeled data. Similarly, the SSL method increases this separability by 11.3x for cough type and 5.1x for severity classifications. Furthermore, the spectral differences in the user-labeled audio segments are amplified in the re-labeled data, resulting in significantly different power spectral densities between healthy and COVID-19 coughs in the 1-1.5 kHz range (p=1.2×10-64), which demonstrates both the increased consistency of the new dataset and its explainability from an acoustic perspective. Finally, we demonstrate how the re-labeled dataset can be used to train a COVID-19 classifier, achieving an AUC of 0.797.

CONCLUSIONS

We propose a SSL expert knowledge aggregation technique for the field of cough sound classification for the first time, and demonstrate how it can be used to combine the medical knowledge of multiple experts in an explainable fashion, thus providing abundant, consistent data for cough classification tasks.

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

The role of lung volume recruitment therapy in neuromuscular disease: a narrative review

Respiratory muscle weakness results in substantial discomfort, disability, and ultimately death in many neuromuscular diseases. Respiratory system impairment manifests as shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing, and chronic ventilatory failure. Ventilatory support (i.e., non-invasive ventilation) is an established and key treatment for the latter. As survival outcomes improve for people living with many neuromuscular diseases, there is a shift towards more proactive and preventative chronic disease multidisciplinary care models that aim to manage symptoms, improve morbidity, and reduce mortality. Clinical care guidelines typically recommend therapies to improve cough effectiveness and mobilise mucus, with the aim of averting acute respiratory compromise or respiratory tract infections. Moreover, preventing recurrent infective episodes may prevent secondary parenchymal pathology and further lung function decline. Regular use of techniques that augment lung volume has similarly been recommended (volume recruitment). It has been speculated that enhancing lung inflation in people with respiratory muscle weakness when well may improve respiratory system "flexibility", mitigate restrictive chest wall disease, and slow lung volume decline. Unfortunately, clinical care guidelines are based largely on clinical rationale and consensus opinion rather than level A evidence. This narrative review outlines the physiological changes that occur in people with neuromuscular disease and how these changes impact on breathing, cough, and respiratory tract infections. The biological rationale for lung volume recruitment is provided, and the clinical trials that examine the immediate, short-term, and longer-term outcomes of lung volume recruitment in paediatric and adult neuromuscular diseases are presented and the results synthesised.

Detecting Childhood Pneumonia Using Handcrafted and Deep Learning Cough Sound Features and Multilayer Perceptron. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38083528 DOI: 10.1109/embc40787.2023.10340477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Pneumonia is one of the leading causes of morbidity and mortality in children. This is especially true in resource poor regions lacking diagnostic facilities, bringing about the need for rapid diagnostic tests for pneumonia. Cough is a common symptom of acute respiratory diseases, including pneumonia, and the sound of cough can be indicative of the pathological variations caused by respiratory infections. As such, in this paper we study objective cough sound evaluation for differentiating between pneumonia and other acute respiratory diseases. We use a dataset of 491 cough sounds from 173 children diagnosed either as having pneumonia or other acute respiratory diseases. We extract features which describe the temporal, spectral, and cepstral characteristics of the cough sound. These features are combined with feature embeddings from a pretrained deep learning network and used to train a multilayer perceptron for classification. The proposed method achieves a sensitivity and specificity of 84% and 73% respectively in differentiating between pneumonia and other acute respiratory diseases using cough sounds alone.

Smart Devices Are Poised to Revolutionize the Usefulness of Respiratory Sounds

The association between breathing sounds and respiratory health or disease has been exceptionally useful in the practice of medicine since the advent of the stethoscope. Remote patient monitoring technology and artificial intelligence offer the potential to develop practical means of assessing respiratory function or dysfunction through continuous assessment of breathing sounds when patients are at home, at work, or even asleep. Automated reports such as cough counts or the percentage of the breathing cycles containing wheezes can be delivered to a practitioner via secure electronic means or returned to the clinical office at the first opportunity. This has not previously been possible. The four respiratory sounds that most lend themselves to this technology are wheezes, to detect breakthrough asthma at night and even occupational asthma when a patient is at work; snoring as an indicator of OSA or adequacy of CPAP settings; cough in which long-term recording can objectively assess treatment adequacy; and crackles, which, although subtle and often overlooked, can contain important clinical information when appearing in a home recording. In recent years, a flurry of publications in the engineering literature described construction, usage, and testing outcomes of such devices. Little of this has appeared in the medical literature. The potential value of this technology for pulmonary medicine is compelling. We expect that these tiny, smart devices soon will allow us to address clinical questions that occur away from the clinic.

Primary site of constriction during the compression phase of cough in healthy young adults

Glottal closure has been considered as the primary constriction point during the compression phase (CP); however, vocal fold adduction alone cannot resist the high pressures, providing motivation to explore other mechanisms contributing to that resistance. The goal of this study was to identify site(s) and degree of constriction during the CP of cough of varying types in healthy young adults. Twenty-five healthy young participants participated in this study. The experimental protocol was comprised of: 1) baseline pulmonary function measures; 2) cough practice to establish weak, moderate and strong coughs; 3) voluntary and reflex cough assessments with fluoroscopy and airflow measures. We used a repeated measures ANOVA to identify whether there are differences in constriction ratio between cough types. There was a significant difference in constriction of varying cough types. Degree of constriction in all cough strengths showed that the glottis was the most constricted area, followed by the laryngeal vestibule, nasopharynx, hypopharynx, oropharynx, and cervical trachea, in order, but stronger cough resulted in more constriction in all areas compared to weaker cough. Degree of constriction in reflex cough showed a similar pattern though there was greater constriction in the oropharynx than the hypopharynx. Airflow measures in voluntary cough were consistent with previous findings. Differences in upper airway constriction during the compression phase of cough may be attributed to differences in motor control between reflex and voluntary cough, and the increased constriction seen during strong cough may reflect increased muscle recruitment during that task. In the future, we can use this knowledge to develop novel methods for cough rehabilitation.

Infectious and Inflammatory Pathways to Cough

Coughing is a dynamic physiological process resulting from input of vagal sensory neurons innervating the airways and perceived airway irritation. Although cough serves to protect and clear the airways, it can also be exploited by respiratory pathogens to facilitate disease transmission. Microbial components or infection-induced inflammatory mediators can directly interact with sensory nerve receptors to induce a cough response. Analysis of cough-generated aerosols and transmission studies have further demonstrated how infectious disease is spread through coughing. This review summarizes the neurophysiology of cough, cough induction by respiratory pathogens and inflammation, and cough-mediated disease transmission.

Clinical utility of preoperative pulmonary function testing in pediatrics

Perioperative respiratory adverse events pose a significant risk in pediatric anesthesia, and identifying these risks is vital. Traditionally, this is assessed using history and examination. However, the perioperative risk is multifactorial, and children with complex medical backgrounds such as chronic lung disease or obesity may benefit from additional objective preoperative pulmonary function tests. This article summarizes the utility of available pulmonary function assessment tools as preoperative tests in improving post-anesthetic outcomes. Currently, there is no evidence to support or discourage any pulmonary function assessment as a routine preoperative test for children undergoing anesthesia. In addition, there is uncertainty about which patients with the known or suspected respiratory disease require preoperative pulmonary function tests, what time period prior to surgery these are required, and whether spirometry or more sophisticated tests are indicated. Therefore, the need for any test should be based on information obtained from the history and examination, the child's age, and the complexity of the surgery.

Coronavirus disease 2019 (Covid-19) outcomes in patients with sarcopenia: A Meta-analysis and Meta-Regression

Background

Sarcopenia has been associated with patients' poor quality of life, disability, and hospitalization. As of today, evidence that highlights the association between sarcopenia and Covid-19 outcomes remains unclear. This study sought to analyze whether patients with sarcopenia are at higher risk for developing poor Covid-19 outcomes.

Methods

Using specific keywords, we comprehensively go through the potential articles on medRxiv, Europe PMC, and PubMed sources until July 31st, 2021. All published studies on sarcopenia and coronavirus disease 2019 were collected. We were using Review Manager 5.4 and Comprehensive Meta-Analysis 3 software to conduct statistical analysis.

Results

There were 9 studies with 492,245 Covid-19 patients included in the analysis. Evaluation of the data gathered yielded an association between sarcopenia and increased severity of Covid-19 (OR 1.99; 95%CI: 1.37–2.90, p = 0.0003, I² = 79%, random-effect modelling); and mortality from Covid-19 (OR 1.96; 95%CI: 1.11–3.46, p = 0.020, I² = 49%, random-effect modelling). The increased risk of developing severe Covid-19 in a sarcopenic patient is also further influenced by cancer.

Conclusions

This study proposes that patients with sarcopenia are at risk of developing poor Covid-19 outcomes. Patients with sarcopenia need special attention and should be prioritized to receive the SARS-CoV-2 vaccine.

Registration details

PROSPERO (CRD42021270725).

An Assistive Coughing Device for Post-Laryngectomy Patients

People who have undergone total laryngectomy typically have difficulties speaking and coughing. Coughing, the protective reflex action where air is rapidly expelled from the lungs to clear the airway, is crucial in everyday life. Insufficiency in coughing can lead to serious chest infections. In this research we present a bionic assistive coughing device (RoboCough) to improve coughing efficacy among laryngectomy patients by increasing pressure and flow rate. RoboCough was designed to mimic the function of the glottis and trachea in the upper respiratory system. Experimental results show a significant increase (t(64) = 4.9, p < 0.0001) in peak cough flow rate and peak cough pressure (t(64) = 12.6, p < 0.0001) among 33 control participants using RoboCough. A pilot study with a smaller cohort of laryngectomy patients shows improvement in peak cough pressure (p = 0.0159) using RoboCough. Preliminary results also show that post-laryngectomy coughs achieved similar peak cough flow (Z = -0.9933, p = 0.32) to the control group’s natural cough. Coughing capabilities could be improved through using RoboCough. Applications of RoboCough include simulation of vocal folds and respiratory conditions, rehabilitation of ineffective coughs from laryngeal and respiratory diseases and as a test-bed for the development of medical devices for respiratory support.

The COUGHVID crowdsourcing dataset, a corpus for the study of large-scale cough analysis algorithms

Cough audio signal classification has been successfully used to diagnose a variety of respiratory conditions, and there has been significant interest in leveraging Machine Learning (ML) to provide widespread COVID-19 screening. The COUGHVID dataset provides over 25,000 crowdsourced cough recordings representing a wide range of participant ages, genders, geographic locations, and COVID-19 statuses. First, we contribute our open-sourced cough detection algorithm to the research community to assist in data robustness assessment. Second, four experienced physicians labeled more than 2,800 recordings to diagnose medical abnormalities present in the coughs, thereby contributing one of the largest expert-labeled cough datasets in existence that can be used for a plethora of cough audio classification tasks. Finally, we ensured that coughs labeled as symptomatic and COVID-19 originate from countries with high infection rates. As a result, the COUGHVID dataset contributes a wealth of cough recordings for training ML models to address the world's most urgent health crises.

Airway Clearance in Tracheomalacia

Airway clearance is an essential part of airway maintenance to ensure the airway lumen is protected against particulate and infectious insults. The mechanisms involved in airway clearance include intrinsic structural and cellular components that can be impaired or inhibited through developmental defects and surgical interventions. Tracheomalacia is a developmental defect of the airway that can contribute to the mechanical failure to clear the airway. This chapter will review the mechanisms of airway clearance and the processes that can impair this vital process.

Functional Respiratory Disorders in Children

Functional respiratory disorders (FRDs) are those characterized by respiratory symptoms without anatomic or organic etiology. Clinicians caring for children encounter these disorders and should be familiar with diagnosis and treatment. FRDs encompass the habit cough syndrome and its variants, vocal cord dysfunction, hyperventilation disorders, functional dyspnea, and sighing syndrome. Failure to identify these disorders results in unnecessary testing and medication. This article reviews the clinical presentation, manifestation, and treatment of respiratory FRDs in children. How health care providers can successfully identify and treat these reversible conditions in the clinical setting is discussed.

Single and sequential voluntary cough in children with chronic spinal cord injury

We investigated the impact of spinal cord injury (SCI) on cough capacity in 10 children (Mean ± SD, age 8 ± 4 years) and compared it to 15 typically developing children (age 8 ± 3 years). Participants underwent spirometry, single and sequential cough assessment with surface-electromyography from respiratory muscles. Inspiratory phase duration, inspiratory phase peak flow, inspiratory phase rise time, compression phase duration, expiratory phase rise time, expiratory phase peak airflow (EPPF) and cough volume acceleration (CVA) parameters of single and sequential cough were measured. Root mean square (RMS) values of right pectoralis-major, intercostal, rectus-abdominus (RA), and oblique (OB) muscles were calculated and mean of three trials were compared. The significance criterion was set at P < 0.05. The SCI group produced significantly lower lung volumes, EPPF, CVA, and RMS values of RA and OB during expiratory phases of single and sequential coughs. The decrease in activation in expiratory muscles in the SCI group accounts for the impaired expiratory flow and may contribute to risk of respiratory complications.

Comparison of physical properties of voluntary coughing, huffing and swallowing in healthy subjects

Coughing, huffing and swallowing protect the airway from aspiration. This study was conducted to compare the physical properties of voluntary coughing, huffing and swallowing in healthy subjects. Ten healthy men were asked to huff, cough and swallow repeatedly. Electromyograms (EMGs) were recorded from the left side of the external oblique (EO), sternocleidomastoid, suprahyoid (SH) and thyrohyoid muscles. Airflow was recorded using a face mask with two-way non-rebreathing valves. The expiratory velocity of huffing and coughing and the SH EMG of all actions presented high intraclass correlation coefficients (> 0.8). The inspiratory and expiratory velocities did not differ significantly between coughing and huffing. The expiratory acceleration of coughing was significantly higher than that of huffing, whereas the expiratory volume of coughing was significantly smaller than that of huffing. The EO EMG of coughing and huffing were significantly larger than that of swallowing. The EO EMG activity during the expiratory phase was significantly higher than that of the other phases of both coughing and huffing. The SH EMG of coughing and huffing were significantly smaller than that of swallowing. Correlation analysis revealed that the expiratory velocity of coughing was strongly positively correlated with that of huffing. The expiratory volume of huffing was significantly positively correlated with hand grip strength. These results suggest that EO and SH muscle activities during huffing or coughing differ those during swallowing, and huffing and coughing may work similarly in expiratory function.

Post-inhalation cough with therapeutic aerosols: Formulation considerations

This review provides an assessment of post-inhalation cough with therapeutic aerosols. Factors that increase cough may be mitigated through design of the drug, formulation, and device. The incidence of cough is typically less than 5% for drugs with a nominal dose less than 1 mg, including asthma and COPD therapeutics. Cough increases markedly as the dose approaches 100 mg. This is due to changes in the composition of epithelial lining fluid (e.g., increases in osmolality, proton concentration). Whether an individual exhibits cough depends on their degree of sensitization to mechanical and chemical stimuli. Hypersensitivity is increased when the drug, formulation or disease result in increases in lung inflammation. Cough related to changes in epithelial lining fluid composition can be limited by using insoluble neutral forms of drugs and excipients.

The prognostic value of spirometric tests in Amyotrophic Lateral Sclerosis patients

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) patients tend to develop progressive respiratory muscle weakness, leading to ventilatory failure and ineffective cough, principal causes of morbidity and mortality. Since patients are usually unaware of these symptoms, these are generally not noticed until the advanced stages and are associated with poor prognosis. The monitoring of respiratory function on a regular basis is therefore of great importance. Despite the availability of several pulmonary function tests, none of them was found to be the best indicator of the disease progression throughout the course of this condition. The main aim of our work was to evaluate the prognostic value of these respiratory measures evaluated in a brief period of observation and their correlation with motor functional impairments in an ALS cohort.

PATIENTS AND METHODS

Patients with ALS who had respiratory assessments performed and functional motor scales administered at baseline and six months later were included. All patients were assessed with forced vital capacity, both in seated and supine position (FVC; sFVC), peak expiratory flow (PEF), peak expiratory cough flow (PCEF), the revised ALS functional rating scale (ALSFRS-R), at baseline and after six months, and their disease progression rate (ΔFS) was obtained.

RESULTS

We included 73 patients with probable or definite ALS according to El-Escorial revised Criteria. At baseline, PCEF and PEF significantly correlated with ALSFRS-R total, bulbar and spinal subscores and ΔFS, while FVC% significantly correlated with ΔFS. After 6 months all the respiratory parameters significantly correlated with ALSFRS-R and all its subscores. Longitudinally, FVC%, sFVC% and PCEF significantly correlated with ΔFS and some of ALSFRS-R subscores. As concerns the survival analysis, monthly declines of FVC% and sFVC%, significantly correlated with the survival. The worse prognosis in terms of survival was finally found in those whose FVC% and sFVC% dropped below their respective cut-offs.

CONCLUSION

Throughout the course of ALS disease, the monitoring of several respiratory markers, namely FVC, sFVC, PEF and PCEF, plays a critical role in predicting the prognosis of these subjects, both in terms of survival and functional ability. The implementation of monthly cut-offs in the evaluation of FVC and sFVC may allow a faster recognition of those patients with worse prognosis and therefore an optimized tailored clinical care, as well as a better stratification in clinical trials.

Singing as an adjunct therapy for children and adults with cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetically inherited, life-threatening condition that affects major organs. The management of cystic fibrosis involves a multi-faceted daily treatment regimen that includes airway clearance techniques, pancreatic enzymes and other medications. Previous studies have found that compliance with this intensive treatment is poor, especially among adolescents. Because of both the nature and consequences of the illness and the relentless demands of the treatment, many individuals with cystic fibrosis have a poor quality of life. Anecdotal reports suggest that singing may provide both appropriate exercise for the whole respiratory system and a means of emotional expression which may enhance quality of life. This is an update of a previously published review.

OBJECTIVES

To evaluate the effects of singing as an adjunct therapy to standard treatment on the quality of life, morbidity, respiratory muscle strength and pulmonary function of children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Group's Cystic Fibrosis Trials Register and the Cochrane Central Register of Controlled Trials. Date of latest search: 07 January 2019.We also searched major allied complementary data bases, and clinical trial registers. Additionally, we handsearched relevant conference proceedings and journals. Date of latest search: 28 March 2019.

SELECTION CRITERIA

Randomised controlled trials in which singing (as an adjunct intervention) is compared with either a control intervention (for example, playing computer games or doing craft activities) or no singing in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Only one eligible trial was available for analysis.

MAIN RESULTS

Since only one small study (n = 40) was included, no meta-analysis could be performed. The included randomised controlled study was of parallel design and undertaken at two paediatric hospitals in Australia. The study evaluated the effects of a singing program on the quality of life and respiratory muscle strength of hospitalised children with cystic fibrosis (mean age 11.6 years, 35% male). While the singing group received eight individual singing sessions, the control group participated in preferred recreational activities, such as playing computer games or watching movies. This study was limited by a small sample size (51 participants) and a high drop-out rate (21%). There were no differences between the groups at either post-intervention or follow-up; although by the end of treatment there were some improvements in some of the domains of the quality of life questionnaire Cystic Fibrosis Questionnaire-Revised (e.g. emotional, social and vitality domains) for both singing and control groups. For the respiratory muscle strength indices, maximal expiratory pressure at follow-up (six to eight weeks post-intervention) was higher in the singing group, mean difference 25.80 (95% confidence interval 5.94 to 45.66). There was no difference between groups for any of the other respiratory function parameters (maximal inspiratory pressure, spirometry) at either post-intervention or follow-up. No adverse effects were observed in the singing group; adverse events for the control group were not reported in the paper.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the effects of singing on quality of life or on the respiratory parameters in people with cystic fibrosis. However, there is growing interest in non-medical treatments for cystic fibrosis and researchers may wish to investigate the impact of this inexpensive therapy on respiratory function and psychosocial well-being further in the future.

Mucus Hydration in Subjects with Stable Chronic Bronchitis: A Comparison of Spontaneous and Induced Sputum

Mucus hydration is important in mucus clearance and lung health. This study sought to test the relative utility of spontaneous sputum (SS) versus the reasonably noninvasive induced sputum (IS) samples for measurement of mucus hydration. SS and IS samples were collected over a 2-day study interval. Sputum was induced with escalating inhaled nebulized 3-5% hypertonic saline. Viscous portions of the samples ("plugs") were utilized for percent solids and total mucin analyses. Cytokines, nucleotides/nucleosides and cell differentials were measured in plugs diluted into 0.1% Sputolysin. Overall, 61.5% of chronic bronchitis (CB) subjects produced a SS sample and 95.2% an IS sample. Total expectorate sample weights were less for the SS (0.94 ± 0.98 g) than the IS (2.67 ± 2.33 g) samples. Percent solids for the SS samples (3.56% ± 1.95; n = 162) were significantly greater than the IS samples (3.08% ± 1.81; n = 121), p = 0.133. Total mucin concentrations also exhibited a dilution of the IS samples: SS = 4.15 ± 3.23 mg/ml (n = 62) versus IS= 3.34 ± 2.55 mg/ml (n = 71) (p = 0.371). Total mucins (combined SS and IS) but not percent solids, were inversely associated with FEV₁ percent predicted (p = 0.052) and FEV₁,/FVC % (p = 0.035). There were no significant differences between sample types in cytokine or differential cell counts. The probability of sample collections was less for SS than IS samples. Measurements of hydration revealed modest dilution of the IS samples compared to SS. Thus for measurements of mucus hydration, both SS and IS samples appear to be largely interchangeable.

Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats

Translational correlates to pain with activities after deep tissue injury have been rarely studied. We hypothesized that deep tissue incision causes greater activation of nociception-transmitting neurons evoked by muscle contraction. In vivo neuronal activity was recorded in 203 dorsal horn neurons (DHNs) from 97 rats after sham, skin-only, or skin + deep muscle incision. We evaluated DHN responses to static, isometric muscle contractions induced by direct electrical stimulation of the muscle. The effect of pancuronium on DHN response to contractions was also examined. Approximately 50% of DHNs with receptive fields in the hindpaw were excited during muscle contraction. One-second .5- and 1.0-g muscle contractions produced greater DHN activity after skin + deep muscle incision (median [interquartile range], 32 [5-39] impulses, P = .021; and 36 [26-46] impulses, P = .006, respectively) than after sham (6 [0-21] and 15 [8-32] impulses, respectively). Neuromuscular blockade with pancuronium inhibited the muscle contractions and DHN activation during electrical stimulation, demonstrating contraction-induced activation. The greater response of spinal DHNs to static muscle contraction after skin + deep muscle incision may model and inform mechanisms of dynamic pain after surgery. PERSPECTIVE: Completion of various activities is an important milestone for recovery and hospital discharge after surgery. Skin + deep muscle incision caused greater activation of nociception-transmitting DHNs evoked by muscle contraction compared with skin-only incision. This result suggests an important contribution of deep muscle injury to activity-evoked hyperalgesia after surgery.

Predicting spirometry readings using cough sound features and regression

OBJECTIVE

Spirometry is a commonly used method of measuring lung function. It is useful in the definitive diagnosis of diseases such as asthma and chronic obstructive pulmonary disease (COPD). However, spirometry requires cooperative patients, experienced staff, and repeated testing to ensure the consistency of measurements. There is discomfort associated with spirometry and some patients are not able to complete the test. In this paper, we investigate the possibility of using cough sound analysis for the prediction of spirometry measurements.

APPROACH

Our approach is based on the premise that the mechanism of cough generation and the forced expiratory maneuver of spirometry share sufficient similarities enabling this prediction. Using an iPhone, we collected mostly voluntary cough sounds from 322 adults presenting to a respiratory function laboratory for pulmonary function testing. Subjects had the following diagnoses: obstructive, restrictive, or mixed pattern diseases, or were found to have no lung disease along with normal spirometry. The cough sounds were automatically segmented using the algorithm described in Sharan et al (2018 IEEE Trans. Biomed. Eng.). We then represented cough sounds with various cough sound descriptors and built linear and nonlinear regression models connecting them to spirometry parameters. Augmentation of cough features with subject demographic data is also experimented with. The dataset was divided into 272 training subjects and 50 test subjects for experimentation.

MAIN RESULTS

The performance of the auto-segmentation algorithm was evaluated on 49 randomly selected subjects from the overall dataset with a sensitivity and PPV of 84.95% and 98.51%, respectively. Our regression models achieved a root mean square error (and correlation coefficient) for standard spirometry parameters FEV1, FVC, and FEV1/FVC of 0.593L (0.810), 0.725L (0.749), and 0.164 (0.547), respectively, on the test dataset. In addition, we could achieve sensitivity, specificity, and accuracy of 70% or higher by applying the GOLD standard for COPD diagnosis on the estimated spirometry test results.

SIGNIFICANCE

The experimental results show high positive correlation in predicting FEV1 and FVC and moderate positive correlation in predicting FEV1/FVC. The results show possibility of predicting spirometry results using cough sound analysis.

Viscoelastic properties of Pseudomonas aeruginosa variant biofilms

Pseudomonas aeruginosa evolves during chronic pulmonary infections of cystic fibrosis (CF) patients, forming pathoadapted variants that are persistent. Mucoid and rugose small-colony variants (RSCVs) are typically isolated from sputum of CF patients. These variants overproduce exopolysaccharides in the biofilm extracellular polymeric substance (EPS). Currently, changes to the biophysical properties of RSCV and mucoid biofilms due to variations in EPS are not well understood. This knowledge may reveal how lung infections resist host clearance mechanisms. Here, we used mechanical indentation and shear rheometry to analyse the viscoelasticity of RSCV and mucoid colony-biofilms compared to their isogenic parent at 2-, 4-, and 6-d. While the viscoelasticity of parental colony-biofilms underwent fluctuating temporal changes, in contrast, RSCV and mucoid colony-biofilms showed a gradual progression to more elastic-solid behaviour. Theoretical indices of mucociliary and cough clearance predict that mature 6-d parental and RSCV biofilms may show reduced cough clearance from the lung, while early mucoid biofilms may show reduced clearance by both mechanisms. We propose that viscoelasticity be considered a virulence property of biofilms.

Evaluation of cough peak expiratory flow as a predictor of successful mechanical ventilation discontinuation: a narrative review of the literature

A crucial step in the transition from mechanical ventilation to extubation is the successful performance of a spontaneous breathing trial (SBT). The American College of Chest Physicians (ACCP) Guidelines recommend removal of the endotracheal tube upon successful completion of a SBT. However, this does not guarantee successful extubation as there remains a risk of re-intubation. Guidelines have outlined ventilator liberation protocols, selected use of non-invasive ventilation on extubation, early mobilization, and dynamic ventilator metrics to prevent and better predict extubation failure. However, a significant percentage of patients still fail mechanical ventilation discontinuation. A common reason for re-intubation is having a weak cough strength, which reflects the inability to protect the airway.

Evaluation of cough strength via objective measures using peak expiratory flow rate is a non-invasive and easily reproducible assessment which can predict extubation failure. We conducted a narrative review of the literature regarding use of cough strength as a predictive index for extubation failure risk. Results of our review show that cough strength, quantified objectively with a cough peak expiratory flow measurement (CPEF), is strongly associated with extubation success. Furthermore, various cutoff thresholds have been identified and can provide reasonable diagnostic accuracy and predictive power for extubation failure.

These results demonstrate that measurement of the CPEF can be a useful tool to predict extubation failure in patients on MV who have passed a SBT. In addition, the data suggest that this diagnostic modality may reduce ICU length of stay, ICU expenditures, and morbidity and mortality.

The Effectiveness of Singing or Playing a Wind Instrument in Improving Respiratory Function in Patients with Long-Term Neurological Conditions: A Systematic Review

BACKGROUND

Many long-term neurological conditions adversely affect respiratory function. Singing and playing wind instruments are relatively inexpensive interventions with potential for improving respiratory function; however, synthesis of current evidence is needed to inform research and clinical use of music in respiratory care.

OBJECTIVE

To critically appraise, analyze, and synthesize published evidence on the effectiveness of singing or playing a wind instrument to improve respiratory function in people with long-term neurological conditions.

DESIGN

Systematic review of published randomized controlled trials and observational studies examining singing or playing wind instruments to improve respiratory function in individuals with long-term neurological conditions.

METHODS

Articles meeting specified inclusion criteria were identified through a search of the Medline, Embase, PsycINFO, Cochrane Library, CINAHL, Web of Science, CAIRSS for Music, WHO International Clinical Trials Registry Platform Search Portal, and AMED databases as early as 1806 through March 2015. Information on study design, clinical populations, interventions, and outcome measures was extracted and summarized using an electronic standardized coding form. Methodological quality was assessed and summarized across studies descriptively.

RESULTS

From screening 584 references, 68 full texts were reviewed and five studies included. These concerned 109 participants. The studies were deemed of low quality, due to evidence of bias, in part due to intervention complexity. No adverse effects were reported. Overall, there was a trend toward improved respiratory function, but only one study on Parkinson's disease had significant between-group differences.

CONCLUSIONS

The positive trend in respiratory function in people with long-term neurological conditions following singing or wind instrument therapy is of interest, and warrants further investigation.

Clinical management of chronic obstructive pulmonary disease patients with muscle dysfunction

Muscle dysfunction is frequently observed in chronic obstructive pulmonary disease (COPD) patients, contributing to their exercise limitation and a worsening prognosis. The main factor leading to limb muscle dysfunction is deconditioning, whereas respiratory muscle dysfunction is mostly the result of pulmonary hyperinflation. However, both limb and respiratory muscles are also influenced by other negative factors, including smoking, systemic inflammation, nutritional abnormalities, exacerbations and some drugs. Limb muscle weakness is generally diagnosed through voluntary isometric maneuvers such as handgrip or quadriceps muscle contraction (dynamometry); while respiratory muscle loss of strength is usually recognized through a decrease in maximal static pressures measured at the mouth. Both types of measurements have validated reference values. Respiratory muscle strength can also be evaluated determining esophageal, gastric and transdiaphragmatic maximal pressures although there is a lack of widely accepted reference equations. Non-volitional maneuvers, obtained through electrical or magnetic stimulation, can be employed in patients unable to cooperate. Muscle endurance can also be assessed, generally using repeated submaximal maneuvers until exhaustion, but no validated reference values are available yet. The treatment of muscle dysfunction is multidimensional and includes improvement in lifestyle habits (smoking abstinence, healthy diet and a good level of physical activity, preferably outside), nutritional measures (diet supplements and occasionally, anabolic drugs), and different modalities of general and muscle training.

Singing as an adjunct therapy for children and adults with cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetically inherited, life-threatening condition that affects major organs. The management of cystic fibrosis involves a multi-faceted daily treatment regimen that includes airway clearance techniques, pancreatic enzymes and other medications. Previous studies have found that compliance with this intensive treatment is poor, especially among adolescents. Because of both the nature and consequences of the illness and the relentless demands of the treatment, many individuals with cystic fibrosis have a poor quality of life. Anecdotal reports suggest that singing may provide both appropriate exercise for the whole respiratory system and a means of emotional expression which may enhance quality of life. This is an update of a previously published review.

OBJECTIVES

To evaluate the effects of singing as an adjunct therapy to standard treatment on the quality of life, morbidity, respiratory muscle strength and pulmonary function of children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Group's Cystic Fibrosis Trials Register and the Cochrane Central Register of Controlled Trials. Date of latest search: 18 February 2016.We also searched major allied complementary data bases, and clinical trial registers. Additionally, we handsearched relevant conference proceedings and journals. Date of latest search: 18 February 2016.

SELECTION CRITERIA

Randomised controlled trials in which singing (as an adjunct intervention) is compared with either a control intervention (for example, playing computer games or doing craft activities) or no singing in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Only one eligible trial was available for analysis.

MAIN RESULTS

Since only one small study (n = 40) was included, no meta-analysis could be performed. The included randomised controlled study was of parallel design and undertaken at two paediatric hospitals in Australia. The study evaluated the effects of a singing program on the quality of life and respiratory muscle strength of hospitalised children with cystic fibrosis (mean age 11.6 years, 35% male). While the singing group received eight individual singing sessions, the control group participated in preferred recreational activities, such as playing computer games or watching movies. This study was limited by a small sample size (51 participants) and a high drop-out rate (21%). There were no significant differences between the groups at either post-intervention or follow up; although by the end of treatment there were some within-group statistically significant increases for both singing and control groups in some of the domains of the quality of life questionnaire Cystic Fibrosis Questionnaire-Revised (e.g. emotional, social and vitality domains). For the respiratory muscle strength indices, maximal expiratory pressure at follow up (six to eight weeks post-intervention) was higher in the singing group, mean difference 25.80 (95% confidence interval 5.94 to 45.66). There was no significant difference between groups for any of the other respiratory function parameters (maximal inspiratory pressure, spirometry) at either post-intervention or follow up.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the effects of singing on quality of life or on the respiratory parameters in people with cystic fibrosis. However, there is growing interest in non-medical treatments for cystic fibrosis and researchers may wish to investigate the impact of this inexpensive therapy on respiratory function and psychosocial well-being further in the future.

Cystic Fibrosis and Other Respiratory Diseases of Impaired Mucus Clearance

Exposed to a diverse array of potentially noxious agents, the respiratory tract is protected by a highly developed innate defense system. Physiologically regulated epithelial ion and water transport coordinated with mucin secretion, beating cilia, and cough results in continuous flow of fluid and mucus over airway surfaces toward the larynx. This cleansing action is the initial and perhaps most quantitatively important innate defense mechanism. Repeated lung infections and eventual respiratory insufficiency characteristic of human cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) illustrate the consequences of impaired mucus clearance. Altered mucus clearance likely contributes to the initiation, progression, and chronicity of other airway diseases characterized by inflammation and mucous secretory cell hyper/metaplasia that afflict millions worldwide, including chronic obstructive pulmonary disease (COPD). This review concisely discusses the pathophysiology of human diseases characterized by genetic defects that impair mucus clearance. It then explores animal models in which components of the mucus clearance system have been disrupted. These models firmly establish the importance of mucus clearance for respiratory health, and will help elucidate disease mechanisms and therapeutic strategies in CF, PCD and COPD.

Muscle dysfunction in chronic obstructive pulmonary disease: update on causes and biological findings

Respiratory and/or limb muscle dysfunction, which are frequently observed in chronic obstructive pulmonary disease (COPD) patients, contribute to their disease prognosis irrespective of the lung function. Muscle dysfunction is caused by the interaction of local and systemic factors. The key deleterious etiologic factors are pulmonary hyperinflation for the respiratory muscles and deconditioning secondary to reduced physical activity for limb muscles. Nonetheless, cigarette smoke, systemic inflammation, nutritional abnormalities, exercise, exacerbations, anabolic insufficiency, drugs and comorbidities also seem to play a relevant role. All these factors modify the phenotype of the muscles, through the induction of several biological phenomena in patients with COPD. While respiratory muscles improve their aerobic phenotype (percentage of oxidative fibers, capillarization, mitochondrial density, enzyme activity in the aerobic pathways, etc.), limb muscles exhibit the opposite phenotype. In addition, both muscle groups show oxidative stress, signs of damage and epigenetic changes. However, fiber atrophy, increased number of inflammatory cells, altered regenerative capacity; signs of apoptosis and autophagy, and an imbalance between protein synthesis and breakdown are rather characteristic features of the limb muscles, mostly in patients with reduced body weight. Despite that significant progress has been achieved in the last decades, full elucidation of the specific roles of the target biological mechanisms involved in COPD muscle dysfunction is still required. Such an achievement will be crucial to adequately tackle with this relevant clinical problem of COPD patients in the near-future.

A Retrospective Examination of Prandial Aspiration in Preterm Infants

Purpose

We conducted this retrospective study to identify potential signs of aspiration in preterm infants based on crib-side nursing documentation.

Study Design and Methods

A total of 2,590 bottle-feedings were examined for signs of distress across 41 preterm infants who were referred for a swallowing evaluation. All infants underwent either a videofluoroscopic swallow study (VSS) or upper gastrointestinal study (GIS). Physiologic and behavioral warning signs were coded across feedings 10 days prior to the imaging study. Presence or absence of documented aspiration during VSS/GIS was coded for each infant.

Results

Distress signs were documented in seven percent of oral feeding attempts. Aspiration was more common when the crib-side nurse documented coughing (LR+, 8.77; 95% CI, .99–77.09), compromised oxygen saturation levels (LR+, 2.15; CI, .86–5.47), and tachypnea (LR+, 2.15; CI, .28–3.01) during bottle-feeding.

Clinical Implications

Evidence-based distress signs that signal increased suspicion for prandial aspiration will facilitate correct clinical judgments at crib-side. Early identification and prevention of prandial aspiration improves health outcomes for preterm infants.

Clinical practice guidelines: Approach to cough in children: The official statement endorsed by the Saudi Pediatric Pulmonology Association (SPPA)

Cough is the most common presenting symptom in primary care settings. Cough can impact a child's activity level and ability to sleep, play or attend school and is often a source of parental anxiety. Cough in children differs from that in adults in terms of presentation, etiology and management. The majority of cough attacks in children are related to previous upper respiratory tract infections and have a self-limited nature. Cough management strategies should focus on characterizing the cough by means of clinical assessment to identify and address its underlying etiology accurately. Clinical algorithms based on acute/chronic presentation and specific/non-specific causes of cough have been developed to provide guidance for clinical practice. The application of children-specific guidelines for the management of cough can lead to earlier cough resolution and improved parental quality of life. This paper presents the clinical statement of the Saudi Pediatric Pulmonology Association (SPPA) in relation to the management of cough in children.

Singing as an adjunct therapy for children and adults with cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetically inherited, life-threatening condition that affects major organs. The management of cystic fibrosis involves a multi-faceted daily treatment regimen that includes airway clearance techniques, pancreatic enzymes and other medications. Previous studies have found that compliance with this intensive treatment is poor, especially among adolescents. Because of both the nature and consequences of the illness and the relentless demands of the treatment, many individuals with cystic fibrosis have a poor quality of life. Anecdotal reports suggest that singing may provide both appropriate exercise for the whole respiratory system and a means of emotional expression which may enhance quality of life.

OBJECTIVES

To evaluate the effects of singing as an adjunct therapy to standard treatment on the quality of life, morbidity, respiratory muscle strength and pulmonary function of children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Group's Cystic Fibrosis Trials Register and the Cochrane Central Register of Controlled Trials. Date of latest search: 31 March 2014.We also searched major allied complementary data bases, and clinical trial registers. Additionally, we handsearched relevant conference proceedings and journals. Date of latest search: 24 May 2012.

SELECTION CRITERIA

Randomised controlled trials in which singing (as an adjunct intervention) is compared with either a control intervention (for example, playing computer games or doing craft activities) or no singing in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Only one eligible trial was available for analysis.

MAIN RESULTS

Since only one small study was included, no meta-analysis could be performed. The included study was a parallel, randomised controlled trial undertaken at two paediatric hospitals in Australia. The study evaluated the effects of a singing program on the quality of life and respiratory muscle strength of hospitalised children with cystic fibrosis (mean age 11.6 years, 35% male). While the singing group received eight individual singing sessions, the control group participated in preferred recreational activities, such as playing computer games or watching movies. This study was limited by a small sample size (51 participants) and a high drop-out rate (21%). There were no significant differences between the groups at either post-intervention or follow up; although by the end of treatment there were some within-group statistically significant increases for both singing and control groups in some of the domains of the quality of life questionnaire Cystic Fibrosis Questionnaire-Revised (e.g. emotional, social and vitality domains). For the respiratory muscle strength indices, maximal expiratory pressure at follow up (six to eight weeks post-intervention) was higher in the singing group, mean difference 25.80 (95% confidence interval 5.94 to 45.66). There was no significant difference between groups for any of the other respiratory function parameters (maximal inspiratory pressure, spirometry) at either post-intervention or follow up.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the effects of singing on quality of life or on the respiratory parameters in people with cystic fibrosis. However, there is growing interest in non-medical treatments for cystic fibrosis and researchers may wish to investigate the impact of this inexpensive therapy on respiratory function and psychosocial well-being further in the future.

Oropharyngeal aspiration and silent aspiration in children

BACKGROUND

Limited information exists about the nature of and factors associated with oropharyngeal aspiration (OPA) and silent aspiration (SA) in children. A prospective study was undertaken to determine the factors associated with fluoroscopically identified OPA and SA.

METHODS

Three hundred children presenting with feeding difficulties underwent a videofluoroscopic swallow study (VFSS) for evaluation of swallowing. Swallowing performance on each food and fluid consistency was rated using the penetration-aspiration scale, and children were classified into the following groups: OPA, SA, overt aspiration (OA), and no aspiration (NA).

RESULTS

OPA occurred in 34% of children; of these, 81% had SA. SA was significantly associated with neurologic impairment (OR, 4.65; 95% CI, 2.26-9.54), developmental delay (OR, 4.62; 95% CI, 2.28-9.35), aspiration lung disease (OR, 3.22; 95% CI, 1.29-8.05), and enteral feeding (OR, 2.03; 95% CI, 1.04-3.62). Similar results were found for OPA. Children with SA were more likely to have neurologic disease (OR, 4.1; 95% CI, 1.1-15.8) than those with OA. Age or gender differences, gastroesophageal reflux disease, recurrent respiratory tract infections, and asthma were no more likely to occur in children with OPA, SA, or OA.

CONCLUSIONS

SA is very common in children with feeding difficulties and is most likely to occur in children with a neurologic problem. Limited medical diagnoses distinguished between aspirators (OPA, SA) and those with NA. VFSS should be performed in children with feeding difficulties and diagnoses of neurologic impairment, cerebral palsy, aspiration lung disease, and/or enteral feeding because of the increased likelihood of SA.

[Incidence of cough after desflurane and sevoflurane administration through a laryngeal mask: a controlled clinical trial]

OBJECTIVE

To determine the incidence of cough with the administration of desflurane and sevoflurane through a laryngeal mask.

METHODS

A double-blind controlled clinical trial in 90 patients who received general anesthesia for ear, nose and throat surgery outpatient. The experimental group (n = 45) inhaled desflurane and the control group (n = 45) inhaled sevoflurane. Rugloop simulation software was used to assure that each patient was under the effect of the induction agent (propofol). The Gasman program was used to ascertain that a minimum alveolar concentration of 1 had been achieved before the hypnotic effect of propofol was lost. Cough was evaluated on the Shahbaz scale during the 10 minutes following induction and at the end of the procedure.

RESULTS

Cough in the first 10 minutes was recorded in 53.6% of patients in the desflurane group and in 2.4% in the sevoflurane group (P < .05). Between-group differences were also evident at the end of surgery (desflurane group, 24%; sevoflurane group, 9.7%; P< .05).

CONCLUSION

The patients who inhaled desflurane through a laryngeal mask had a higher incidence of cough than those who inhaled sevoflurane. The mechanism by which cough is being triggered by desflurane should be studied to determine whether the effect is chemical or mechanical and whether it is acting in the larynx or in the distal portion of the lung.

Food for Thought on Pediatric Feeding and Swallowing

“Food for Thought” provides an opportunity for review of pertinent topics to add to updates in areas of concern for professionals involved with feeding and swallowing issues in infants and children. Given the frequency with which speech-language pathologists (SLPs) make decisions to alter feedings when young infants demonstrate silent aspiration on videofluoroscopic swallow studies (VFSS), the need for increased understanding about cough and its development/maturation is a high priority. In addition, understanding of the role(s) of laryngeal chemoreflexes (LCRs), relationships (or lack of relationships) between cough and esophagitis, gastroesophageal reflux (GER), and chronic salivary aspiration is critical. Decision making regarding management must take into account multiple systems and their interactions in order to provide safe feeding for all children to meet nutrition and hydration needs without being at risk for pulmonary problems. The responsibility is huge and should encourage all to search the literature so that clinical practice is as evidence-based as possible; this often requires adequate understanding of developmentally appropriate neurophysiology and function.