Non-pharmacological techniques for the extremes of the cough spectrum

Hypotussic cough in persons with dysphagia: biobehavioral interventions and pathways to clinical implementation

Cough is a powerful, protective expulsive behavior that assists in maintaining respiratory health by clearing foreign material, pathogens, and mucus from the airways. Therefore, cough is critical to survival in both health and disease. Importantly, cough protects the airways and lungs from both antegrade (e.g., food, liquid, saliva) and retrograde (e.g., bile, gastric acid) aspirate contents. Aspiration is often the result of impaired swallowing (dysphagia), which allows oral and/or gastric contents to enter the lung, especially in individuals who also have cough dysfunction (dystussia). Cough hyposensitivity, downregulation, or desensitization- collectively referred to as hypotussia- is common in individuals with dysphagia, and increases the likelihood that aspirated material will reach the lung. The consequence of hypotussia with reduced airway clearance can include respiratory tract infection, chronic inflammation, and long-term damage to the lung parenchyma. Despite the clear implications for health, the problem of managing hypotussia in individuals with dysphagia is frequently overlooked. Here, we provide an overview of the current interventions and treatment approaches for hypotussic cough. We synthesize the available literature to summarize research findings that advance our understanding of these interventions, as well as current gaps in knowledge. Further, we highlight pragmatic resources to increase awareness of hypotussic cough interventions and provide support for the clinical implementation of evidence-based treatments. In culmination, we discuss potential innovations and future directions for hypotussic cough research.

Cough Assessment and Management in Pulmonary Rehabilitation- A Canadian Survey

Pulmonary rehabilitation is a cornerstone intervention for controlling respiratory symptoms in people with chronic respiratory diseases. Chronic cough affects up to 90% of people with chronic respiratory diseases, however, it is currently unknown whether chronic cough is assessed and/or managed in pulmonary rehabilitation. This study aimed to determine if and how chronic cough is assessed and managed in pulmonary rehabilitation. This was a cross-sectional study. Pulmonary rehabilitation programs in Canada were identified via online websites. A representative from each program was invited to complete an online survey including the following topics: program demographics, assessment and management practices, and barriers and facilitators. Of 133 programs contacted, 31 returned a completed survey (23% response rate). Approximately half (52%) of respondents reported enrolling patients with chronic cough. Of those, 45% reported assessing and 62% reported intervening in chronic cough. Inadequate knowledge of assessment and management techniques was commonly identified to be a barrier and increased education was suggested as a possible facilitator. Based on pulmonary rehabilitation programs that responded to our survey, chronic cough is a prevalent symptom; however, it is scarcely assessed and managed. A need for structured education and the use of standardised strategies were reported as facilitators to the assessment and management of chronic cough in pulmonary rehabilitation.

Characterization of Ethyl Butyrate-Induced Cough Before and After Breath Control Techniques in Healthy Adults

PURPOSE

Methods for cough elicitation frequently involve aerosolized tussive agents. Here, we sought to determine whether healthy individuals demonstrate a quantifiable cough response after inhaling a volatile ester and if breath control techniques modify this chemically induced cough response.

METHOD

Sixty adult male and female participants inhaled prepared liquid dilutions of ethyl butyrate dissolved in paraffin oil at 20%, 40%, and 60% v/v concentrations in triplicate, with presentation order randomized. We delivered stimuli through a face mask connected to an olfactometer and respiratory pneumotachograph. Participants rated sensations of their urge to cough and pleasantness of the odor while cough airflow was measured. Following baseline testing, participants were randomized to implement pursed-lip breathing or slow-paced breathing after inhaling ethyl butyrate to determine the effects of breath control on cough measures.

RESULTS

Inhaled ethyl butyrate elicited cough in 70% of participants. Higher concentrations of ethyl butyrate resulted in significantly greater sensation of the urge to cough, F(2, 80) = 10.72, p < .001, and significantly more generated coughs, F(2, 63) = 13.14, p < .001. Compared to baseline, participants rated significantly decreased urge to cough during breath control techniques, F(1, 40) = 11.01, p = .0019. No significant changes were observed in the number of generated coughs between baseline and breath control techniques, F(1, 31) = 7.23, p = .01.

CONCLUSIONS

Airborne ethyl butyrate is a tussigenic agent in humans. Our findings provide opportunities for future research directions in normal and disordered cough responses to volatile compounds.

Effect of Capsaicin Atomization-Induced Cough on Sputum Excretion in Tracheotomized Patients After Hemorrhagic Stroke: A Randomized Controlled Trial

Background Timely and effective removal of respiratory secretions is of great significance for tracheotomized patients. The purpose of this study is to investigate the effectiveness of capsaicin nebulization to stimulate cough to promote early clearance of respiratory secretions in tracheotomized patients after hemorrhagic stroke. Method This study implemented a randomized controlled design. Sixty-three patients who were tracheotomized following a hemorrhagic stroke completed this randomized controlled trial. In the control group, 33 cases were given a routine care after tracheotomy. In the intervention group, 30 cases were given a capsaicin solution nebulization in addition to the routine care. The daily sputum output and the number of sputum suctioning were observed. The differences in sputum viscosity, cough function, and Clinical Pulmonary Infection Score (CPIS) were compared between the two groups before and after the intervention. Vital sign changes during capsaicin nebulization and suctioning were compared between the two groups in a pilot study. Results The daily sputum output of the capsaicin intervention group was significantly higher than that of the control group (p < .05). The number of sputum suctioning of capsaicin group was less than that of the control group after intervention (p < .05). The CPIS score of the capsaicin group was lower than that of the control group (p < .05) after a 1-week intervention. Patients' heart rate, respiratory rate, and oxygen saturation during capsaicin nebulization were not statistically different from those during routine sputum suctioning (p > .05). Conclusions Capsaicin atomization-induced cough can effectively promote sputum excretion of hemorrhagic stroke patients undergoing tracheotomy and has a good safety profile. The Clinical Trial registration number of this study is ChiCTR2000037772 (http://www.chictr.org.cns). Supplemental Material https://doi.org/10.23641/asha.16821352.

A Review on Cough Augmentation Techniques: Assisted Inspiration, Assisted Expiration and Their Combination

Cough is an important mechanism of airway clearance. In patients who present weak and ineffective cough, augmentation techniques aim to assist or simulate the maneuver. These techniques target different phases of the cough cycle, mainly the inspiratory and expiratory phases, through assisted inspiration, assisted expiration and their combination. They include the manual hyperinflation, ventilator hyperinflation, glossopharyngeal breathing, manually assisted cough and mechanical insufflator-exsufflator, each applied individually or in different combinations. The aim of this review is to investigate the effectiveness and safety of cough augmentation techniques. Findings support that all commonly used techniques can theoretically improve airway clearance, as they generate higher cough peak flows compared to unassisted cough. Still, the studies assessing cough augmentation present considerable limitations and the direct comparison of different techniques is challenging. Current evidence indicate that cough peak flow shows higher increase with the combination of assisted inspiration and expiration, and improvement is greater in patients with lower unassisted values. Associated adverse events are infrequent.

Could reflex cough induced through nebulized capsaicin achieve airway clearance in patients with acute retention of lung secretions?

Nasotracheal suctioning (NTS) is a procedure commonly performed by respiratory physiotherapists and nurses to remove excess respiratory secretions from the tracheobronchial tree in a self-ventilating, non-intubated and non-tracheotomized patient. NTS is an important treatment modality for patients with acute secretion retention who are at high risk of progressive respiratory deterioration and arrest. However, NTS is a blind invasive procedure with risk of serious adverse events, and the patient experience of NTS is often extremely negative. Capsaicin, a substance extracted from cayenne pepper, elicits reflex coughs when inhaled. It is hypothesized that capsaicin-induced reflex cough may offer an alternative treatment option to NTS. It is suggested that repeated reflex cough bouts, elicited through inhalation of nebulized capsaicin via a facemask, could achieve clearance of retained secretions from the tracheobronchial tree to the oropharynx, thereby avoiding the need for NTS. This hypothesis is supported by preliminary cough flow data from a stroke trial. Stroke patients underwent assessments of peak cough flow (PCF, a measure of cough effectiveness) of both maximal volitional cough and capsaicin-induced reflex cough. In a sub-group of 20 stroke patients with weak volitional cough (mean PCF 220 L/min, SD 80), PCF of capsaicin-induced reflex cough was on average 184 L/min (SD 130) higher than PCF of subjects' maximal volitional cough effort. Cough flow traces indicate a pattern of cough augmentation during consecutive reflex cough bouts. It is suggested that the hypothesis may best be tested in a pragmatic applied clinical study, i.e. through the application of nebulized capsaicin in relevant clinical situations, as opposed to observational or experimental physiological studies.