Breathing-swallowing discoordination is associated with frequent exacerbations of COPD

Chronic intermittent hypoxia reveals role of the Postinspiratory Complex in the mediation of normal swallow production

Obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder that results in multiple bouts of intermittent hypoxia. OSA has many neurological and systemic comorbidities, including dysphagia, or disordered swallow, and discoordination with breathing. However, the mechanism in which chronic intermittent hypoxia (CIH) causes dysphagia is unknown. Recently, we showed the postinspiratory complex (PiCo) acts as an interface between the swallow pattern generator (SPG) and the inspiratory rhythm generator, the preBötzinger complex, to regulate proper swallow-breathing coordination (Huff et al., 2023). PiCo is characterized by interneurons co-expressing transporters for glutamate (Vglut2) and acetylcholine (ChAT). Here we show that optogenetic stimulation of ChATcre:Ai32, Vglut2cre:Ai32, and ChATcre:Vglut2FlpO:ChR2 mice exposed to CIH does not alter swallow-breathing coordination, but unexpectedly disrupts swallow behavior via triggering variable swallow motor patterns. This suggests that glutamatergic-cholinergic neurons in PiCo are not only critical for the regulation of swallow-breathing coordination, but also play an important role in the modulation of swallow motor patterning. Our study also suggests that swallow disruption, as seen in OSA, involves central nervous mechanisms interfering with swallow motor patterning and laryngeal activation. These findings are crucial for understanding the mechanisms underlying dysphagia, both in OSA and other breathing and neurological disorders.

Chronic Intermittent Hypoxia reveals role of the Postinspiratory Complex in the mediation of normal swallow production

Obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder that results in multiple bouts of intermittent hypoxia. OSA has many neurologic and systemic comorbidities including dysphagia, or disordered swallow, and discoordination with breathing. However, the mechanism in which chronic intermittent hypoxia (CIH) causes dysphagia is unknown. Recently we showed the Postinspiratory complex (PiCo) acts as an interface between the swallow pattern generator (SPG) and the inspiratory rhythm generator, the preBötzinger Complex, to regulate proper swallow-breathing coordination (Huff et al., 2023). PiCo is characterized by interneurons co-expressing transporters for glutamate (Vglut2) and acetylcholine (ChAT). Here we show that optogenetic stimulation of ChATcre:Ai32, Vglut2cre:Ai32, and ChATcre:Vglut2FlpO:ChR2 mice exposed to CIH does not alter swallow-breathing coordination, but unexpectedly disrupts swallow behavior via triggering variable swallow motor patterns. This suggests, glutamatergic-cholinergic neurons in PiCo are not only critical for the regulation of swallow-breathing coordination, but also play an important role in the modulation of swallow motor patterning. Our study also suggests that swallow disruption, as seen in OSA, involves central nervous mechanisms interfering with swallow motor patterning and laryngeal activation. These findings are crucial for understanding the mechanisms underlying dysphagia, both in OSA and other breathing and neurological disorders.

Targeting malnutrition in patients with COPD in the community

The number of individuals living with chronic obstructive pulmonary disease (COPD) is increasing, but nutritional care can be inconsistent, especially in those with stable COPD. Historically, poor appetite and weight loss have been considered the norm during the progression of COPD into the later stage. However, it is imperative that nutritional assessment, support and management is undertaken from diagnosis, because malnutrition can lead to exacerbations of COPD and increased hospitalisation. Poor nutrition in individuals with COPD has been shown to predict an increase in mortality and with the care of patients taking place principally in the community, the nutritional aspects of care should be assessed, monitored and managed, in accordance with the latest guidance. The lack of a nutritional Quality Outcome Framework indicator for COPD can leave nutrition overlooked, but evidence shows that screening, assessment and planning can have an overall positive impact.

Videofluoroscopic measures of swallowing in people with stable COPD compared to healthy aging

PURPOSE

Swallowing impairment is a serious extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD). Previous studies suggest that individuals with stable COPD show atypical values for several videofluoroscopy measures of swallowing, compared to healthy adults under age 60. However, it is unclear to what degree these changes are attributable to healthy aging. In this study, we aimed to clarify how swallowing in people with stable COPD differs from age-matched healthy controls.

METHODS

We performed a retrospective analysis of videofluoroscopy data from two previously-collected datasets: a) a sample of 28 adults with stable COPD (18 male); b) a sample of 76 healthy adults, from which 28 adults were selected, matched for sex and age to participants in the COPD cohort. In both prior studies, participants swallowed 20% w/v liquid barium prepared in different consistencies (thin; mildly, moderately, and extremely thick). Blinded duplicate ratings were performed according to a standard procedure, yielding measures of laryngeal vestibule closure (LVC) integrity and timing, swallow timing, upper esophageal sphincter (UES) opening, pharyngeal constriction and pharyngeal residue. Mann-Whitney U tests and odds ratios were performed to determine significant group differences (p<.05).

RESULTS

Across the consistencies tested, participants with COPD showed significantly shorter durations of LVC, earlier onsets and shorter durations of UES opening, and reduced pharyngeal constriction. No significant differences were seen in other measures.

CONCLUSION

These results point to features of swallowing in people with stable COPD that differ from changes seen with healthy aging, and which represent risks for potential aspiration.

Cross-System Integration of Respiration and Deglutition: Function, Treatment, and Future Directions

Swallowing occurs preferentially in the expiratory phase of the quiet breathing cycle and at mid-to-low tidal volume. This coordinative pattern imparts important biomechanical advantages to swallowing and airway protection and facilitate laryngeal elevation, laryngeal vestibular and vocal fold closure, and cricopharyngeal sphincter opening. This preferred coordinative relationship between breathing and swallowing is impaired in a variety of patient populations, including head and neck cancer survivors with dysphagia. We developed a training protocol to re-establish more optimal phasing of swallowing with breathing in these patients with striking outcomes, including reduced swallowing physiological impairments and improved airway protection. This motivated us to continue to refine and expand this training protocol and develop new assistive technologies for swallowing monitoring outside of the lab. In this review, we highlight the origins of our optimal respiratory-swallowing coordination hypothesis, describe the biomechanical advantages it provides, carefully describe our training protocol and findings, and chart a course for the next phase of this work. Our overall goal is to harness technology combined with carefully constructed learning paradigms to improve the lives of patients with impaired respiratory-swallowing coordination consequent to a variety of pathologies including head and neck cancer and degenerative neurological conditions such as Parkinson's disease.

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 prospective examination of swallow and cough dysfunction after lung transplantation

OBJECTIVES

Swallow and cough dysfunction are possible surgical complications of lung transplantation (LT). We examined voluntary cough strength, sensorimotor reflexive cough integrity, and swallow-related respiratory rate (RR) across swallowing safety and aspiration response groups in recovering LT recipients.

METHODS

Forty-five LT recipients underwent flexible endoscopic evaluation of swallowing indexed by the validated Penetration Aspiration Scale. RR before and after a 3-ounce water drinking task was measured. Voluntary and reflexive cough screening were performed to index motor and sensory outcomes. T-tests, one-way ANOVAs, and chi-square (odds ratios) were used.

RESULTS

60% of patients exhibited laryngeal penetration (n = 27) and 40% demonstrated tracheal aspiration (n = 18); 72% (n = 13) demonstrated silent aspiration. Baseline RR was higher in aspirators versus non-aspirators (26.5 vs. 22.6, p = 0.04) and in silent aspirators compared to non-silent aspirators (27.9 vs. 20.7, p = 0.01). RR change post-swallowing did not differ between aspiration response groups; however, it was significantly higher in aspirators compared to non-aspirators (3 vs. -2, p = 0.02). Compared to non-silent aspirators, silent aspirators demonstrated reduced voluntary cough peak expiratory flow (PEF; 166 vs. 324 L/min, p = 0.01). PEF, motor and urge to cough reflex cough ratings did not differ between aspirators and non-aspirators. Silent aspirators demonstrated a 7.5 times higher odds of failing reflex cough screening compared to non-silent aspirators (p = 0.07).

CONCLUSIONS

During the acute recovery period, all LT participants demonstrated some degree of unsafe swallowing and reduced voluntary cough strength. Silent aspirators exhibited elevated RR, reduced voluntary cough physiologic capacity to defend the airway, and a clinically distinguishable blunted motor response to reflex cough screening.

Screening for oropharyngeal dysphagia in hospitalized COVID-19 patients: a prospective study

PURPOSE

To screen for oropharyngeal dysphagia (OD) in hospitalized COVID-19 patients.

METHODS

A descriptive longitudinal study was conducted on 500 adult patients with confirmed COVID-19 in the age range of 19-65 years who were admitted to the main university isolation hospital (whether admitted in the ward or the intensive care unit). Screening for OD was done using the Arabic version of the Eating Assessment Tool (EAT-10) and the Yale swallow protocol.

RESULTS

45.4% of the admitted and 40.97% of the discharged COVID-19 patients had a positive screen for OD. Several risk factors for OD could be detected. These include older age, longer duration of presenting symptoms of COVID-19, presence of ageusia and anosmia, presence of dysphonia, ICU admission, lower oxygen saturation, higher respiratory rate, presence of OD at admission, longer duration of hospital stay, and use of noninvasive ventilation (NIV) and/or invasive mechanical ventilation (IMV).

CONCLUSIONS

Screening for OD in hospitalized COVID-19 patients is a mandatory procedure, whether for admitted or discharged patients.

Risk Factors for Dysphagia in Patients Hospitalized with COVID-19

Patients hospitalized with COVID-19 may be at risk for dysphagia and vulnerable to associated consequences. We investigated predictors for dysphagia and its severity in a cohort of patients hospitalized with COVID-19 at a single hospital center. A large level I trauma center database was queried for all patients hospitalized with COVID-19. Demographics, medical information associated with COVID-19, specific to dysphagia, and interventions were collected. 947 patients with confirmed COVID-19 met the criteria. 118 (12%) were seen for a swallow evaluation. Individuals referred for evaluation were significantly older, had a lower BMI, more severe COVID-19, and higher rates of intubation, pneumonia, mechanical ventilation, tracheostomy placements, prone positioning, and ARDS. Pneumonia (OR 3.57, p = 0.004), ARDS (OR 3.57, p = 0.029), prone positioning (OR 3.99, p = 0.036), ventilation (OR 4.01, p = 0.006), and intubation (OR 4.75, p = 0.007) were significant risk factors for dysphagia. Older patients were more likely to have more severe dysphagia such that for every 1-year increase in age, the odds of severe dysphagia were 1.04 times greater (OR 1.04, p = 0.028). Patients hospitalized with COVID-19 are at risk for dysphagia. We show predictive variables that should be considered when referring COVID-19 patients for dysphagia services to reduce time to intervention/evaluation.

Antimicrobial therapies for prevention of recurrent acute exacerbations of COPD (AECOPD): beyond the guidelines

Background

Unfortunately, many COPD patients continue to exacerbate despite good adherence to GOLD Class D recommended therapy. Acute exacerbations lead to an increase in symptoms, decline in lung function and increased mortality rate. The purpose of this review is to do a literature search for any prophylactic anti-microbial treatment trials in GOLD class D patients who ‘failed’ recommended therapy and discuss the role of COPD phenotypes, lung and gut microbiota and co-morbidities in developing a tailored approach to anti-microbial therapies for high frequency exacerbators.

Main text

There is a paucity of large, well-conducted studies in the published literature to date. Factors such as single-centre, study design, lack of well-defined controls, insufficient patient numbers enrolled and short follow-up periods were significant limiting factors in numerous studies. One placebo-controlled study involving more than 1000 patients, who had 2 or more moderate exacerbations in the previous year, demonstrated a non-significant reduction in exacerbations of 19% with 5 day course of moxifloxacillin repeated at 8 week intervals. In Pseudomonas aeruginosa (Pa) colonised COPD patients, inhaled antimicrobial therapy using tobramycin, colistin and gentamicin resulted in significant reductions in exacerbation frequency. Viruses were found to frequently cause acute exacerbations in COPD (AECOPD), either as the primary infecting agent or as a co-factor. However, other, than the influenza vaccination, there were no trials of anti-viral therapies that resulted in a positive effect on reducing AECOPD. Identifying clinical phenotypes and co-existing conditions that impact on exacerbation frequency and severity is essential to provide individualised treatment with targeted therapies. The role of the lung and gut microbiome is increasingly recognised and identification of pathogenic bacteria will likely play an important role in personalised antimicrobial therapies.

Conclusion

Antimicrobial therapeutic options in patients who continue to exacerbate despite adherence to guidelines-directed therapy are limited. Phenotyping patients, identification of co-existing conditions and assessment of the microbiome is key to individualising antimicrobial therapy. Given the impact of viruses on AECOPD, anti-viral therapeutic agents and targeted anti-viral vaccinations should be the focus of future research studies.

Singing Experience Influences RSST Scores

It has recently been shown that the aging population is refractory to the maintenance of swallowing function, which can seriously affect quality of life. Singing and vocal training contribute to mastication, swallowing and respiratory function. Previous studies have shown that singers have better vocal cord health. No consensus has been reached as to how vocal training affects swallowing ability. Our study was designed to establish evidence that singers are statistically superior at inducing the swallowing reflex. To test our hypothesis, we undertook a clinical trial on 55 singers and 141 non-singers (mean age: 60.1 ± 11.7 years). This cross-sectional study with propensity score matching resulted in significant differences in a repetitive saliva swallowing test among singers: 7.1 ± 2.4, n = 53 vs. non-singers: 5.9 ± 1.9, n = 53, p < 0.05. We conclude that singing can serve an important role in stabilizing the impact of voluntary swallowing on speech.

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.

Effects of high flow nasal cannula on the coordination between swallowing and breathing in postextubation patients, a randomized crossover study

BACKGROUND

Timing of swallows in relation to respiratory phases is associated with aspiration events. Oxygen therapy possibly affects the timing of swallows, which may alter airway protective mechanisms.

OBJECTIVES

To compare the coordination between swallowing and respiration during water infusion in post-extubation patients using high flow nasal oxygen (HFNO) with the coordination in those using low flow nasal oxygen (LFNO).

METHODS

We conducted a randomized controlled crossover study in post-extubation patients. The patients extubated within 48 h were randomly assigned to two groups, namely, HFNO and LFNO. The eligible patients in each group received either HFNO with fraction of inspired oxygen (FiO₂) 0.35, flow 50 L per minute (LPM), and temperature 34 °C or LFNO 5 LPM for 5 min. The coordination between swallowing and respiration was observed during continuous infusion of 10-ml water one minute three times. Respiratory phases and swallowing were monitored using electrocardiogram (EKG)-derived respiratory signals and submental electromyography (EMG), respectively. The swallowing frequency and timing of swallows in relation to respiratory phases were recorded. The coordination between swallowing and respiration was classified into 4 patterns, namely I, E, I-E, and E-I swallows. (I; inspiration and E; expiration) Subsequently, after a 5-min washout period, the patients were switched to the other type of oxygen therapy using the same procedure. The Wilcoxon Signed-Rank Test was used for statistical analysis.

RESULTS

A total of 22 patients with a mean age of 56 years were enrolled in the study. The major indication for invasive mechanical ventilation was pneumonia with a median duration of endotracheal intubation of 2.5 days. The median total swallowing numbers (three minutes) were 18.5 times in the HFNO period and 21 times in the LFNO period (p = NS). The most common swallowing pattern was E-swallow. The patients using HFNO had higher numbers of E-swallow pattern (74.3% in HFNO vs 67.6% in LFNO; p = 0.048) and lower numbers of I-swallow pattern (14.3% in HFNO vs 23.1% in LFNO; p = 0.044). The numbers of other swallowing patterns were not different between the 2 groups.

CONCLUSIONS

Compared with LFNO, HFNO significantly increased the E-swallow and decreased the I-swallow in post-extubation patients. The findings indicated that HFNO might reduce a risk of aspiration during the post-extubation period. Clinical trial No.: Thai clinical trial TCTR20200206004 Registered February 4, 2020. URL: http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=5740 .

An Exploration of Lung Volume Effects on Swallowing in Chronic Obstructive Pulmonary Disease

Purpose Chronic obstructive pulmonary disease (COPD) limits respiration, which may negatively impact airway safety during swallowing. It is unknown how differences in lung volume in COPD may alter swallowing physiology. This exploratory study aimed to determine how changes in lung volume impact swallow duration and coordination in persons with stable state COPD compared with older healthy volunteers (OHVs). Method Volunteers ≥ 45 years with COPD (VwCOPDs; n = 9) and OHVs (n = 10) were prospectively recruited. Group and within-participant differences were examined when swallowing at different respiratory volumes: resting expiratory level (REL), tidal volume (TV), and total lung capacity (TLC). Participants swallowed self-administered 20-ml water boluses by medicine cup. Noncued (NC) water swallows were followed by randomly ordered block swallowing trials at three lung volumes. Estimated lung volume (ELV) and respiratory-swallow patterning were quantified using spirometry and respiratory inductive plethysmography. Manometry measured pharyngeal swallow duration from onset of base of tongue pressure increase to offset of negative pressure in the pharyngoesophageal segment. Results During NC swallows, the VwCOPDs swallowed at lower lung volumes than OHVs (p = .011) and VwCOPDs tended to inspire after swallows more often than OHVs. Pharyngeal swallow duration did not differ between groups; however, swallow duration significantly decreased as the ELV increased in VwCOPDs (p = .003). During ELV manipulation, the COPD group inspired after swallowing more frequently at REL than at TLC (p = .001) and at TV (p = .002). In conclusion, increasing respiratory lung volume in COPD should improve safety by reducing the frequency of inspiration after a swallow.

Tongue strength and swallowing dynamics in chronic obstructive pulmonary disease

Background

Swallowing disorders occur in COPD, but little is known about tongue strength and mastication. This is the first assessment in COPD of tongue strength and a test of mastication and swallowing solids (TOMASS).

Methods

Anterior tongue strength measures were obtained in 18 people with COPD, aged 73±11 years (mean±sd), and 19 healthy age-matched controls, aged 72±6 years. Swallowing dynamics were assessed using an eating assessment tool (EAT-10), timed water swallow test (TWST), and TOMASS. Swallowing measures were compared to an inhibitory reflex (IR) in the inspiratory muscles to airway occlusion (recorded previously in the same participants).

Results

Tongue strength was similar between COPD and controls (p=0.715). Self-assessed scores of dysphagia EAT-10 were higher (p=0.024) and swallowing times were prolonged for liquids (p=0.022) and solids (p=0.003) in the COPD group. During TWST, ∼30% of COPD group showed clinical signs of airway invasion (cough and wet voice), but none in the control group. For solids, the COPD group had ∼40% greater number of chews (p=0.004), and twofold-higher number of swallows (p=0.0496). Respiratory rate was 50% higher in COPD group than controls (p <0.001). The presence of an IR was not related to better swallowing outcomes, but signs of airway invasion were associated with a delayed IR.

Conclusion

Dysphagia in stable COPD is not due to impaired anterior tongue strength, but rather swallowing–breathing discoordination. To address dysphagia, aspiration and acute exacerbations in COPD, therapeutic targets to improve swallowing dynamics could be investigated further.

In this novel study of swallowing in COPD, there was no difference in tongue strength when compared to healthy controls, and in COPD participants with airway invasion, the inhibitory reflex to airway occlusion in inspiratory muscles was delayedhttps://bit.ly/3h4EeKw

Decreased Tongue Strength is Related to Skeletal Muscle Mass in COPD Patients

Dysphagia is frequently observed in patients with chronic obstructive pulmonary disease (COPD). Decreased tongue strength is one of the causes of dysphagia, and it is often observed in patients with sarcopenia. Sarcopenia is also frequently observed in COPD patients. We hypothesized that tongue strength is lower in COPD patients compared to normal subjects. This was a single-center, observational, cross-sectional study. Maximum tongue pressure (MTP) was measured in 27 patients with COPD and 24 age-matched control subjects. We also evaluated handgrip strength, gait speed, and appendicular skeletal muscle mass to define subjects as having sarcopenia. We used bioelectrical impedance analysis to assess body composition. The eating assessment test-10 was used to diagnose dysphagia. MTP was significantly lower in COPD patients than in control subjects (33.8 ± 8.4 vs 38.0 ± 5.3; p = 0.032). All measures of muscle and fat free body mass, handgrip strength, and gait speed were also significantly lower in COPD patients compared to control subjects (p < 0.01). The prevalence of sarcopenia in COPD patients was higher than that in control subjects (6/27 versus 0/24; p = 0.007), but the prevalence of dysphagia was not different between groups (COPD: 5/27, versus control: 1/24; p = 0.112). MTP was moderately correlated with skeletal muscle mass index (r = 0.56, p = 0.003) and handgrip strength (r = 0.43, p = 0.027) in COPD patients. Tongue strength was lower in COPD patients compared to normal subjects, and decreased tongue strength may be correlated with sarcopenia in COPD patients.

Inspiratory muscle responses to sudden airway occlusion in chronic obstructive pulmonary disease

Brief airway occlusion produces a potent reflex inhibition of inspiratory muscles that is thought to protect against aspiration. Its duration is prolonged in asthma and obstructive sleep apnea. We assessed this inhibitory reflex (IR) in chronic obstructive pulmonary disease (COPD). Reflex responses to brief (250 ms) inspiratory occlusions were measured in 18 participants with moderate to severe COPD (age 73 ± 11 yr) and 17 healthy age-matched controls (age 72 ± 6 yr). We compared the incidence and properties of the IR between groups. Median eupneic preocclusion electromyographic activity was higher in the COPD group than controls (9.4 μV vs. 5.2 μV, P = 0.001). Incidence of the short-latency IR was higher in the COPD group compared with controls (15 participants vs. 7 participants, P = 0.010). IR duration for scalenes was similar for the COPD and control groups [73 ± 37 ms (means ± SD) and 90 ± 50 ms, respectively] as was the magnitude of inhibition. IRs in the diaphragm were not detected in the controls but were present in 9 participants of the COPD group (P = 0.001). The higher incidence of the IR in the COPD group than in the age-matched controls may reflect the increased inspiratory neural drive in the COPD group. This higher drive counteracts changes in chest wall and lung mechanics. However, when present, the reflex was similar in size and duration in the two groups. The relation between the IR in COPD and swallowing function could be assessed.NEW & NOTEWORTHY A potent short-latency reflex inhibition of inspiratory muscles produced by airway occlusion was tested in people with COPD and age-matched controls. The reflex was more prevalent in COPD, presumably due to an increased neural drive to breathe. When present, the reflex was similar in duration in the two groups, longer than historical data for younger control groups. The work reveals novel differences in reflex control of inspiratory muscles due to aging as well as COPD.

Swallowing and Voice Outcomes in Patients Hospitalized With COVID-19: An Observational Cohort Study

Objective

To evaluate the presentations and outcomes of inpatients with coronavirus disease 2019 (COVID-19) presenting with dysphonia and dysphagia to investigate trends and inform potential pathways for ongoing care.

Design

Observational cohort study.

Setting

An inner-city National Health Service Hospital Trust in London, United Kingdom.

Participants

All adult inpatients hospitalized with COVID-19 (N=164) who were referred to Speech and Language Therapy (SLT) for voice and/or swallowing assessment for 2 months starting in April 2020.

Interventions

SLT assessment, advice, and therapy for dysphonia and dysphagia.

Main Outcome Measures

Evidence of delirium, neurologic presentation, intubation, tracheostomy, and proning history were collected, along with type of SLT provided and discharge outcomes. Therapy outcome measures were recorded for swallowing and tracheostomy pre- and post-SLT intervention and Grade Roughness Breathiness Asthenia Strain Scale for voice.

Results

Patients (N=164; 104 men) aged 56.8±16.7 years were included. Half (52.4%) had a tracheostomy, 78.7% had been intubated (mean, 15±6.6d), 13.4% had new neurologic impairment, and 69.5% were delirious. Individualized compensatory strategies were trialed in all and direct exercises with 11%. Baseline assessments showed marked impairments in dysphagia and voice, but there was significant improvement in all during the study (P<.0001). On average, patients started some oral intake 2 days after initial SLT assessment (interquartile range [IQR], 0-8) and were eating and drinking normally on discharge, but 29.3% (n=29) of those with dysphagia and 56.1% (n=37) of those with dysphonia remained impaired at hospital discharge. A total of 70.9% tracheostomized patients were decannulated, and the median time to decannulation was 19 days (IQR, 16-27). Among the 164 patients, 37.3% completed SLT input while inpatients, 23.5% were transferred to another hospital, 17.1% had voice, and 7.8% required community follow-up for dysphagia.

Conclusions

Inpatients with COVID-19 present with significant impairments of voice and swallowing, justifying responsive SLT. Prolonged intubations and tracheostomies were the norm, and a minority had new neurologic presentations. Patients typically improved with assessment that enabled treatment with individualized compensatory strategies. Services preparing for COVID-19 should target resources for tracheostomy weaning and to enable responsive management of dysphagia and dysphonia with robust referral pathways.

Quantitative Videofluoroscopic Analysis of Swallowing Physiology and Function in Individuals With Chronic Obstructive Pulmonary Disease

Purpose Dysphagia is a serious extra pulmonary manifestation of chronic obstructive pulmonary disease (COPD). However, the nature of abnormalities in swallowing physiology in COPD has yet to be clearly established. We explored the frequency of swallowing measures outside the healthy reference range in adults with COPD. Method Participants were 28 adults aged 41-79 years (18 men, 20 women) with stable COPD. Disease severity was classified as GOLD (Global Initiative For Chronic Obstructive Lung Disease) Stages 1 (4%), 2 (25%), 3 (53%), and 4 (18%). Participants underwent a videofluoroscopy and swallowed 20% w/v thin barium in, followed by 20% w/v mildly, moderately, and extremely thick barium prepared with a xanthan gum thickener. Blinded duplicate ratings of swallowing safety, efficiency, kinematics, and timing were performed according to the ASPEKT method (Analysis of Swallowing Physiology: Events, Kinematics and Timing). Comparison data for healthy adults aged < 60 years were extracted from an existing data set. Chi-square and Fisher's exact tests compared the frequencies of measures falling < 1 SD/ > 1 SD from mean reference values (or < the first or > the third quartile for skewed parameters). Results Participants with COPD did not display greater frequencies of penetration-aspiration, but they were significantly more likely (p < .05) to display incomplete laryngeal vestibule closure (LVC), longer time-to-LVC, and shorter LVC duration. They also displayed significantly higher frequencies of short upper esophageal sphincter opening, reduced pharyngeal constriction, and pharyngeal residue. Conclusion This analysis reveals differences in swallowing physiology in patients with stable COPD characterized by impaired safety related to the mechanism, timing, and duration of LVC and by impaired swallowing efficiency with increased pharyngeal residue related to poor pharyngeal constriction.

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

Introduction

Dysphagia is a newly acknowledged multifactorial risk factor for the exacerbation of chronic obstructive pulmonary disease (COPD). Effective screening methods are awaited. We performed a prospective study to evaluate the impact of musculature and breathing-swallowing discoordination on the exacerbation of COPD with a novel swallowing monitor using a piezoelectric sensor.

Patients and Methods

This was the second part of a prospective study of patients with COPD from the Iizuka COPD cohort. Seventy patients with stable COPD underwent dysphagia screening, skeletal muscle mass index (SMI) and tongue pressure measurements, and swallowed 3 mL and 30 mL of water while wearing a swallowing monitor. Patients were followed for one year.

Results

During the follow-up period, 28 patients experienced exacerbations (E group), and 42 had none (non-E group). There was no significant difference in tongue pressure measurements between the two groups. The SMI in the E group was significantly lower than that in the non-E group. Among the swallowing monitor measurements, the 3 mL I-SW% (the percentage of swallows in which inspiration preceded the swallow [out of ten 3 mL swallows]) was significantly lower in the E group than in the non-E group.

Conclusion

Breathing-swallowing coordination is an independent factor related to the exacerbation of COPD. Not only the presence of discoordination but also the inability to produce an airway protection mechanism may contribute to more frequent aspiration and exacerbations.

Shedding Light on Dysphagia Associated With COVID-19: The What and Why

The most common symptom of COVID-19 in critically ill patients is ARDS (acute respiratory distress syndrome), with many patients requiring invasive or noninvasive respiratory support in the intensive care unit. Oropharyngeal dysphagia may be a consequence of the respiratory-swallowing incoordination common in ARDS or may occur following the respiratory support interventions. In this commentary, we highlight the risk and complications of oropharyngeal dysphagia in patients with COVID-19 and urge medical and rehabilitation professionals to consider dysphagia a prognostic complication, provide appropriate referrals, and initiate early interventions as appropriate.

Predictive Roles of the Repetitive Saliva Swallowing Test (RSST) in Aspiration Pneumonia and Other Respiratory Diseases: Does the RSST Have a Predictive Role in Aspiration Pneumonia and Other Respiratory Diseases?

Patients with dysphagia do not always present with subjective symptoms. However, asymptomatic dysphagia can also cause clinical issues, especially in those with respiratory conditions. Therefore, adequate screening is an essential beginning to their care. The repetitive saliva swallowing test (RSST) is one of the safest screening methods for dysphagia; it can be easily performed by nonprofessionals in any setting. There is evidence of its predictive values in aspiration pneumonia, chronic obstructive pulmonary disease (COPD), artificial ventilation, and other conditions. Additionaly, it has recently been found to be a strong predictor of the risk of future COPD exacerbation. The cost-effectiveness, harmlessness, and simplicity make it an optimal screening method for the large population of patients with respiratory conditions, although different cutoff values may be useful in different populations. It also takes into account multiple aspects of the swallowing ability, such as respiration, musculature, cognition, and general well-being.

Repetitive Saliva Swallowing Test Predicts COPD Exacerbation

Introduction

Predicting phenotypes at risk of chronic obstructive pulmonary disease (COPD) exacerbation is extremely important. Dysphagia is becoming recognized as one of these phenotypes. A convenient method of screening for dysphagia and COPD exacerbation risk is desired. The repetitive saliva swallowing test (RSST) is one of the least invasive dysphagia screening methods. We previously reported the possible relation between the RSST result and COPD exacerbation in a retrospective study. Based on this, we performed a prospective study to evaluate the efficacy of RSST as a predictor of COPD exacerbation and to determine its optimal cut-off value for COPD.

Methods

Seventy patients with COPD were recruited. Patients underwent the following dysphagia screening tests: the 10-item Eating Assessment Tool, Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease, RSST, water swallowing test, and simple swallow provocation test. After one year, they were classified into two groups according to the presence of COPD exacerbation during the follow-up period.

Results

Twenty-seven patients had one or more exacerbations in the past year. During the follow-up period, 28 patients had one or more exacerbations (E group), and 42 had none (non-E group). There were no significant differences between the groups except for the presence of past exacerbations and the results of the RSST, when the cut-off value was set at 2, 3, 4, or 5 swallows. The number of swallows in the RSST was significantly lower in the E group than in the Non-E group. A cut-off value of 5 was the most effective. The time to first exacerbation was significantly longer in those with an RSST value of >5. The RSST was more reliable for differentiating the E group and non-E group than the presence of exacerbation in the past year (hazard ratios: 13.78 and 2.70, respectively).

Conclusion

An RSST cut-off value of 5 may be a strong predictor of COPD exacerbation.

Comparison of three frailty models and a sarcopenia model in elderly patients with chronic obstructive pulmonary disease

AIM

Frailty and sarcopenia affect the prognosis and quality of life of patients with chronic obstructive pulmonary disease (COPD). However, it remains uncertain which model is the most suitable for evaluating vulnerability in patients with COPD. We evaluated the validity of three frailty models - the Kihon Checklist (KCL), the Japanese version of the Cardiovascular Health Study and the Study of Osteoporotic Fractures - and one sarcopenia model for older patients with COPD.

METHODS

This cross-sectional study included 201 older (aged ≥65 years) outpatients with COPD. We used three frailty models and one sarcopenia model to identify their correlation with various indices that can evaluate the status of COPD and determine the most ideal model for evaluating vulnerability in patients with COPD.

RESULTS

The highest prevalence of frailty (38%) and lowest prevalence of robustness (26%) were observed using the KCL. Although all models reflected the characteristics of COPD, the KCL yielded the strongest correlations with clinically important physical, psychological and prognostic indices. The KCL yielded statistically significant differences in almost all indices among the three intergroup comparisons (robust, pre-frailty and frailty). The KCL was superior in extracting mood disorders to the other models.

CONCLUSION

Although all investigated models were useful, the KCL was the most suitable for evaluating the frailty status and might enable interventions in patients with COPD. Geriatr Gerontol Int 2019; 19: 896-901.

Effects of noninvasive ventilation on the coordination between breathing and swallowing in patients with chronic obstructive pulmonary disease

Purpose

As shown in our previous study, inspiration after swallowing (SW-I) increases during the bi-level positive airway pressure ventilation (BiPAP) in healthy subjects because swallowing-associated non-inspiratory flow (SNIF) triggers inspiratory support, while SW-I during continuous positive pressure ventilation (CPAP) is rare. In the present study, we evaluated the coordination between breathing and swallowing during spontaneous breathing, BiPAP, and CPAP in patients with chronic obstructive pulmonary disease (COPD).

Patients and methods

This study is a prospective intervention study at the Hoshigaoka Medical Center (November 01, 2015–April 30, 2018). We simultaneously recorded the respiratory flow, laryngeal motion, and swallowing sounds during saliva swallowing in patients with COPD. We estimated the respiratory phase after swallowing, frequency of SNIF, the duration of the respiratory pause during swallowing, and timing of swallowing in the respiratory cycle and compared these parameters among control, CPAP, and BiPAP conditions.

Results

The expiration after swallowing (SW-E) frequency was associated with the occurrence of SNIF (p<0.01), pause duration ≤0.8 s (p<0.01), and timing of swallowing at the intermediate respiratory phase (50–80% of the respiratory cycle from the onset of inspiration) (p<0.01). In particular, the occurrence of SNIF most substantially affected the SW-E frequency. The SW-I frequencies under the control, CPAP, and BiPAP conditions were 35.0%, 3.0%, and 37.7%, respectively. The pause durations were shorter during CPAP and BiPAP than under the control condition (p<0.01). During CPAP, the occurrence rates of SW-E. Residual denotes the percentage difference between observed and expected values (residual =10.8: p<0.01) and SNIF (residual =9.1: p<0.01) were significantly increased, and timing of swallowing shifted toward the intermediate respiratory phase (residual=3.5: p<0.01).

Conclusion

CPAP decreases the SW-I frequency, increases the SNIF occurrence, and normalizes the timing of swallowing, all of which suggest that CPAP alleviates the risk of aspiration in patients with COPD.

Swallow-breathing coordination during incremental ascent to altitude

Swallow and breathing are highly coordinated behaviors reliant on shared anatomical space and neural pathways. Incremental ascent to high altitudes results in hypoxia/hypocapnic conditions altering respiratory drive, however it is not known whether these changes also alter swallow. We examined the effect of incremental ascent (1045 m, 3440 m and 4371 m) on swallow motor pattern and swallow-breathing coordination in seven healthy adults. Submental surface electromyograms (sEMG) and spirometry were used to evaluate swallow triggered by saliva and water infusion. Swallow-breathing phase preference was different between swallows initiated by saliva versus water. With ascent, saliva swallows changed to a dominate pattern of occurrence during the transition from inspiration to expiration. Additionally, water swallows demonstrated a significant decrease in submental sEMG duration and a shift in submental activity to earlier in the apnea period, especially at 4371 m. Our results suggest that there are changes in swallow-breathing coordination and swallow production that likely increase airway protection with incremental ascent to high altitude. The adaptive changes in swallow were likely due to the exposure to hypoxia and hypocapnia, along with airway irritation.

Inappropriate Timing of Swallow in the Respiratory Cycle Causes Breathing-Swallowing Discoordination

Rationale: Swallowing during inspiration and swallowing immediately followed by inspiration increase the chances of aspiration and may cause disease exacerbation. However, the mechanisms by which such breathing–swallowing discoordination occurs are not well-understood.

Objectives: We hypothesized that breathing–swallowing discoordination occurs when the timing of the swallow in the respiratory cycle is inappropriate. To test this hypothesis, we monitored respiration and swallowing activity in healthy subjects and in patients with dysphagia using a non-invasive swallowing monitoring system.

Measurements and Main Results: The parameters measured included the timing of swallow in the respiratory cycle, swallowing latency (interval between the onset of respiratory pause and the onset of swallow), pause duration (duration of respiratory pause for swallowing), and the breathing–swallowing coordination pattern. We classified swallows that closely follow inspiration (I) as I-SW, whereas those that precede I as SW-I pattern. Patients with dysphagia had prolonged swallowing latency and pause duration, and tended to have I-SW or SW-I patterns reflecting breathing–swallows discoordination.

Conclusions: We conclude that swallows at inappropriate timing in the respiratory cycle cause breathing–swallowing discoordination, and the prolongation of swallowing latency leads to delayed timing of the swallow, and results in an increase in the SW-I pattern in patients with dysphagia.