Breathing-Swallowing Discoordination and Inefficiency of an Airway Protective Mechanism Puts Patients at Risk of COPD Exacerbation

Swallowing disorder - a possible therapeutic target for preventing COPD exacerbations

Dysphagia is a common comorbidity of chronic obstructive pulmonary disease (COPD). In this review article, we show that swallowing disorder can be detected at its early stage as a manifestation of breathing-swallowing discoordination. Furthermore, we provide evidence that low-pressure continuous airway pressure (CPAP) and transcutaneous electrical sensory stimulation using interferential current (IFC-TESS) counteract swallowing disorders and may reduce exacerbations in patients with COPD. Our first prospective study showed that inspiration immediately before or after swallowing is associated with COPD exacerbation. However, the inspiration before swallowing (I-SW) pattern could be interpreted as an airway-protecting behavior. Indeed, the second prospective study showed that the I-SW pattern is more frequently observed in patients who did not experience exacerbations. As potential therapeutic candidates, CPAP normalizes the timing of swallowing, and IFC-TESS applied to the neck acutely facilitates swallowing and chronically improves nutrition and airway protection. Further studies are necessary to elucidate whether such interventions reduce exacerbations in patients with COPD.

A Paradigm Shift in the Diagnosis of Aspiration Pneumonia in Older Adults

In older adults, community-acquired pneumonia (CAP) is often aspiration-related. However, as aspiration pneumonia (AP) lacks clear diagnostic criteria, the reported prevalence and clinical management vary greatly. We investigated what clinical factors appeared to influence the diagnosis of AP and non-AP in a clinical setting and reconsidered a more clinically relevant approach. Medical records of patients aged ≥75 years admitted with CAP were reviewed retrospectively. A total of 803 patients (134 APs and 669 non-APs) were included. The AP group had significantly higher rates of frailty, had higher SARC-F scores, resided in institutions, had neurologic conditions, previous pneumonia diagnoses, known dysphagia, and were more likely to present with vomiting or coughing on food. Nil by mouth orders, speech therapist referrals, and broad-spectrum antibiotics were significantly more common, while computed tomography scans and blood cultures were rarely performed; alternative diagnoses, such as cancer and pulmonary embolism, were detected significantly less. AP is diagnosed more commonly in frail patients, while aspiration is the underlying aetiology in most types of pneumonia. A presumptive diagnosis of AP may deny patients necessary investigation and management. We suggest a paradigm shift in the way we approach older patients with CAP; rather than trying to differentiate AP and non-AP, it would be more clinically relevant to recognise all pneumonia as just pneumonia, and assess their swallowing functions, causative organisms, and investigate alternative diagnoses or underlying causes of dysphagia. This will enable appropriate clinical management.

The prevalence of oropharyngeal dysphagia in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Oropharyngeal dysphagia (OD) in chronic obstructive pulmonary disease (COPD) patients seriously influence the long-term prognosis of COPD patients. The aim of this study was to assess the prevalence and risk factors of OD in patients with COPD through a systematic review and meta-analysis of observational studies.

METHODS

We identified all observational studies on the prevalence of OD in COPD patients by searching PubMed, Embase, the Cochrane Library, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), China National Knowledge Infrastructure (CNKI), the China Biomedical Literature Service System (CBM), the Wanfang Database, and the WeiPu (VIP) databases from database establishment to 1 December 2020.

RESULTS

    Results of the meta-analysis showed that the prevalence of OD in COPD patients was 32.7% (95%CI=30.1, 35.4, I2=91.5%). Dyspnea, gastroesophageal reflux disease(GERD), xerostomia, sputum bacteria, poor physical capacity, poor quality of life, and high CRP level are the risk factors for OD in COPD patients.

CONCLUSION

: The prevalence of OD in COPD patients is high. There were some differences in OD among COPD patients with different sex, ages, continents, evaluation methods, patient source and COPD exacerbation.

Effect of tongue strength on clinical outcomes of patients: A systematic review

OBJECTIVES

Whether decreased tongue strength is associated with poor clinical outcomes is unclear. This systematic review investigated the effect of decreased tongue strength on the clinical outcomes of adults requiring medical treatment.

DESIGN

Systematic review.

SETTING AND PARTICIPANTS

Systematic reviews, randomized control trials, intervention studies, and longitudinal observational studies involving patients with decreased tongue strength requiring medical treatment were included.

METHODS

Articles published between January 2000 and June 2021 were retrieved from MEDLINE, CINAHL, Ichushi-web (in Japanese), Web of Science, ClinicalTrials.gov, UMIN, the Cochrane Library, and Cochrane Central Register of Controlled Trials. Risk of bias was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies. The study protocol was pre-registered in XXX.

RESULTS

After screening 3040 articles and excluding duplicates, 74 articles were retrieved; after full-text evaluation of the 74 articles, seven articles (with 787 patients) were found to meet the inclusion criteria. The cut-off values for determining decreased tongue strength ranged from 13.8 to 21.6 kPa. Patients with decreased tongue strength had poorer recovery of their swallowing function, higher incidence of pneumonia, and poorer life expectancy than those with high tongue strength. However, tongue strength in older patients with decreased tongue strength increased when they performed physical exercise interventions and followed strict nutritional management plans.

CONCLUSIONS

Decreased tongue strength was related to poor clinical outcomes in in- and outpatients. Oral frailty in older patients should be given increased attention in hospitals, and further research is needed to improve the clinical outcomes for older people with reduced tongue strength.

Swallowing Dynamics and Breathing-Swallowing Coordination Are Altered in Patients with Mild Cognitive Impairment

INTRODUCTION

Postinspiratory activity, which is essential for laryngeal closure during swallowing to prevent aspiration of food into the airways, is reduced in a mouse model of tauopathy. Therefore, we hypothesized that patients at the stage of mild cognitive impairment (MCI) exhibit alterations in swallowing dynamics and coordination between swallowing and breathing.

METHODS

We examined breathing-swallowing coordination in patients with MCI. Patients who scored ≥24 on the Mini-Mental State Examination and <26 on the Japanese version of the Montreal Cognitive Assessment were recruited at Sumoto Itsuki Hospital. Parameters associated with breathing-swallowing coordination were assessed using a combination of two sensors: a respiratory flow sensor and a piezoelectric sensor attached to the skin surface of the anterior neck.

RESULTS

Nineteen patients met the criteria for MCI; 16 of these patients (79.5 ± 9.1 years old) scored <3 on the 10-item Eating Assessment Tool and were enrolled in the study. Their data were compared with those of an age-matched elderly cohort (79.9 ± 2.9 years old). The frequencies of swallowing during inspiration and swallowing immediately followed by inspiration in patients with MCI were 6.9% and 9.6%, respectively; these frequencies were not significantly different from those of the age-matched elderly cohort. However, the timing of swallowing in the respiratory cycle was significantly delayed in the MCI patients, and both time from the onset to the peak of laryngeal elevation and the duration between the onset of rapid laryngeal elevation and the time when the larynx returned to the resting position were significantly lengthened in this group.

CONCLUSION

At the stage of MCI, breathing-swallowing coordination has already started to decline.

Interferential Current Stimulation for Swallowing Disorders in Chronic Obstructive Pulmonary Disease: A Preliminary Study

Objectives:

Swallowing function is affected in patients with chronic obstructive pulmonary disease (COPD), putting them at risk of exacerbation of COPD. We previously reported the effectiveness of the repetitive saliva swallowing test (RSST) in screening for patients at risk of COPD exacerbation. However, evidence on how to improve swallowing function in this population is extremely limited. Interferential current transcutaneous electrical sensory stimulation (IFC-TESS) stimulates the larynx and pharynx, thereby improving their sensory function. IFC-TESS is an emerging tool to enhance airway protection and increase swallowing frequency; however, its safety and efficacy in patients with COPD is unknown. Therefore, we performed a preliminary prospective study focusing on stable COPD patients.

Methods:

Patients with stable COPD who were hospitalized for yearly evaluation were recruited. Patients were included if their RSST was 5 or less. Nurses carried out IFC-TESS twice daily for 10 days. Swallow screening results were compared before and after the 10-day intervention.

Results:

Ten patients were included in the study. The IFC-TESS intervention was performed safely. Patients and nurses reported no discomfort or concerns regarding the intervention. The EAT-10 and RSST scores improved significantly after the intervention, and tongue pressure also tended to improve.

Conclusions:

IFC-TESS may be a promising intervention to improve swallowing in patients with COPD who are easily fatigued and struggle to perform swallowing exercises.

Dysphagia in non-intubated patients affected by COVID-19 infection

Purpose

Patients affected by COVID-19 are assumed to be at high risk of developing swallowing disorders. However, to our best knowledge, data on the characteristics and incidence of dysphagia associated with COVID-19 are lacking, especially in non-intubated patients. Therefore, we investigated the onset of swallowing disorders in patients with laboratory-confirmed COVID-19 infection who have not been treated with invasive ventilation, in order to evaluate how the virus affected swallowing function regardless of orotracheal intubation.

Methods

We evaluated 41 patients admitted to the COVID department of our Hospital when they had already passed the acute phase of the disease and were therefore asymptomatic but still positive for SARS-CoV-2 RNA by RT-PCR. We examined patients’ clinical history and performed the Volume-Viscosity Swallow Test (VVST). Each patient also answered the Swallowing Disturbance Questionnaire (SDQ). After 6 months, we performed a follow-up in patients with swallowing disorders.

Results

Eight of 41 patients (20%) presented with dysphagia symptoms during hospitalization and 2 of them (25%) still presented a SDQ high score and swallowing disorders with liquid consistency after 6 months.

Conclusion

Non-intubated patients can experience various grades of swallowing impairment that probably directly related to pulmonary respiratory function alterations and viral direct neuronal lesive activity. Although these symptoms show natural tendency to spontaneous resolution, their impact on a general physical impaired situation should not be underestimated, since it can adversely affect patients’ recovery from COVID-19 worsening health outcomes.