Protective role of aerodigestive reflexes against aspiration: study on subjects with impaired and preserved reflexes

Listening for Dysphagia: Voice Quality Sequelae of Material in the Airway

PURPOSE

Postswallow voice abnormality is often assumed to indicate the presence of material in the laryngeal airway (MIA), but prior research has not shown definitive evidence of a causal relationship. This study investigated if endoscopically confirmed MIA (prandial material or secretions) generates specific voice quality attributes that can be perceptually identified by experienced listeners.

METHOD

Forty-four dysphagic adults underwent endoscopic evaluation of swallowing. Time-linked audiovisual recordings of pre- and postswallow phonation were analyzed to determine the presence, amount, and location of prandial material or secretions in the larynx during phonation. Expert listeners completed auditory-perceptual ratings of phonation samples.

RESULTS

Voice quality ratings did not differ significantly when there was MIA during postswallow phonation. However, judgments of voice quality abnormality for MIA samples were elevated when analyses controlled for effects of baseline dysphonia. Listeners were most likely to perceive voice quality abnormality when larger amounts of secretions were present, as compared to prandial material. Interrater reliability was variable and ranged from low to moderate across perceptual parameters.

CONCLUSIONS

MIA during phonation occurred for many participants, but perception of voice quality abnormality was variable when MIA was present. Baseline dysphonia is common among individuals with dysphagia and may limit perception of voice quality abnormalities generated by MIA. Secretions in the laryngeal airway may have a greater impact on voice quality parameters.

Dysphagia management during COVID-19 pandemic: A review of the literature and international guidelines

In this review, we present the safest and most effective diagnosis and treatment approaches to dysphagia during the novel coronavirus-2019 (COVID-19) pandemic in the light of available data, relevant literature, and personal experiences. Evaluations for dysphagia patients should be based on clinical assessment during the COVID-19 pandemic and instrumental assessment should be planned for very few number of patients. The main approach to rehabilitation must depend on compensatory methods, texture-modified foods, and postural strategies. Direct treatment methods should be avoided and home-based exercise programs should be encouraged. It is also obvious that there is a need for the development of new strategies for telemedicine/telerehabilitation practices in the new world order.

Spontaneous Swallowing Frequency, Dysphagia, and Drooling in Children With Cerebral Palsy

OBJECTIVE

To evaluate relationships between spontaneous swallowing frequency, dysphagia, and drooling in children with cerebral palsy. Spontaneous swallowing frequency was predicted to be inversely related to both dysphagia and drooling among children with cerebral palsy. A secondary objective compared patterns among spontaneous swallowing frequency, drooling, and age in healthy children vs children presenting with cerebral palsy.

DESIGN

Cross sectional study.

SETTING

Children with cerebral palsy were tested at a Cerebral Palsy Reference Center in a university hospital. Healthy children were tested in their home setting.

PARTICIPANTS

Twenty children with cerebral palsy were recruited from the local registry for cerebral palsy children and purposive sampling among parents. A group of 30 healthy children was recruited by purposive sampling among family, friends, and the local community. Children below 1 year of age up to 5 years of age were included in the healthy group. This age range was targeted to maximize the potential for drooling in this group.

MAIN OUTCOME MEASURES

Both groups provided data on spontaneous swallowing frequency (swallows per minute, or SPM), dysphagia, and drooling. Motor impairment was documented in the children with cerebral palsy.

RESULTS

SPM was significantly lower in children with cerebral palsy. Among children with cerebral palsy, SPM correlated significantly with dysphagia severity and trended toward a significant correlation with drooling at rest. In this subgroup, SPM was not correlated with age or degree of motor impairment. Dysphagia was significantly correlated with drooling at rest and both dysphagia and drooling at rest were correlated with degree of motor impairment. The 2 groups did not differ in the degree of drooling at rest. Among healthy children, age but not SPM demonstrated a significant inverse correlation with drooling quotient at rest.

CONCLUSIONS

Spontaneous swallowing frequency is related to dysphagia and drooling in children with cerebral palsy. The pattern of relationships among spontaneous swallowing frequency and drooling is different between children with cerebral palsy and younger healthy children.

Assessment of dysarthria and dysphagia in patients with amyotrophic lateral sclerosis: Review of the current evidence

Bulbar dysfunction is a common presentation of amyotrophic lateral sclerosis (ALS) and significantly impacts quality of life of people with ALS (PALS). The current paper reviews measurements of dysarthria and dysphagia specific to ALS to identify efficient and valid assessment measures. Using such assessment measures will lead to improved management of bulbar dysfunction in ALS. Measures reviewed for dysarthria in PALS are organized into three categories: acoustic, kinematic, and strength. A set of criteria are used to evaluate the effectiveness of the measures' identification of speech impairments, measurement of functional verbal communication, and clinical applicability. Assessments reviewed for dysphagia in PALS are organized into six categories: patient reported outcomes, dietary intake, pulmonary function and airway defense capacity, bulbar function, dysphagia/aspiration screens, and instrumental evaluations. Measurements that have good potential for clinical use are highlighted in both topic areas. Additionally, areas of improvement for clinical practice and research are identified and discussed. In general, no single speech measure fulfilled all the criteria, although a few measures were identified as potential diagnostic tools. Similarly, few objective measures that were validated and replicated with large sample sizes were found for diagnosis of dysphagia in PALS. Importantly, clinical applicability was found to be limited; thus, a collaborative team focused on implementation science would be helpful to improve the clinical uptake of assessments. Overall, the review highlights the need for further development of clinically viable and efficient measurements that use a multidisciplinary approach.

Predicting Gag, Discomfort, and Laryngeal Visualization in Patients Undergoing Flexible Laryngoscopy with Stroboscopy

OBJECTIVE

To investigate potential associations between the Predictive Gagging Survey (PGS) with patient experience of gag and discomfort as well as provider perception of patient gag and level of laryngeal visualization during flexible laryngoscopy with stroboscopy (FL-S).

METHODS

A total of 53 adult patients undergoing FL-S were recruited for this prospective non-controlled study. PGS was completed before FL-S. Patients rated perceived level of gag and discomfort on a 10-point severity scale after FL-S. Additionally, providers completed a Gagging Severity Index (GSI) reflecting their impression of patient gag and level of laryngeal visualization following FL-S. Spearman rank correlation coefficients were used to assess associations.

RESULTS

There was a positive association with PGS score and patient perception of gagging (0.34; P = .013) and patient perception of discomfort (0.38; P = .005). No significant association was found between PGS score and provider GSI (-0.12; P = .39) or level of laryngeal visualization (0.15; P = .29). A negative association was found between level of laryngeal visualization and patient perception of gagging (-0.34; P = .012) and discomfort (-0.44; P = .001). No significant differences were found between current and former smokers compared to never smokers for GSI or patient-perceived gag or discomfort.

CONCLUSIONS

While not predictive of GSI or level of laryngeal visualization, the PGS was found to be a useful tool in predicting patient experience of gagging and discomfort during FL-S, further reinforcing the subjective experience of this procedure. Use of the PGS may be helpful in identifying specific candidates who may struggle with subjective discomfort or gagging during FL-S for future studies considering interventions to manage and meaningfully decrease discomfort. Having such an instrument is important given the low number of individuals who struggle with discomfort during the exam.

Questionnaire survey on pharyngolaryngeal sensation evaluation regarding dysphagia in Japan

OBJECTIVE

The objective is to conduct a questionnaire survey regarding pharyngolaryngeal sensation evaluation in dysphagia to understand the current situation in Japan.

METHOD

The questionnaire was sent to the councilor of the Society of Swallowing and Dysphagia of Japan and the Japanese Society of Dysphagia Rehabilitation-Certified Clinician. The prospective questionnaire survey included the questions listed below: Q1: What do you think of the importance of pharyngolaryngeal sensory evaluation? Q2: Select one of the essential swallowing sensations. Q3: Select one of the following regarding the frequency of sensory examination of the larynx. Q4: Select the proportion of cases the sensory test results affect. Q5: As a pharyngolaryngeal sensory evaluation method in swallowing function evaluation, please fill in the table below for the frequency, difficulty, and effectiveness of the following tests, such as gag reflex, touching the larynx by endoscopy, touching the larynx by the probe with endoscopy, cough reflex test, swallowing provocation test.

RESULTS

The essential swallowing sensations of mechanical stimulation, chemical stimulation, thermal stimulation were 84.9%, 5.4%, and 9.7%, respectively. The frequency of touching the larynx by endoscopy in the otolaryngology group and cough reflex test in dentistry was significantly higher than the other groups (p < 0.05). The correlation between the frequency and difficulty or effectiveness of the sensory tests indicated that the frequency and difficulty are significantly correlated between each item.

CONCLUSION

Our results aid in increasing understanding and selection of pharyngolaryngeal sensation evaluation for dysphagia patients.

Inter-rater and test-retest reliability of the "standardized endoscopic swallowing evaluation for tracheostomy decannulation in critically ill neurologic patients"

Background

Removal of a tracheostomy tube in critically ill neurologic patients is a difficult issue, particularly due to the high incidence of oropharyngeal dysphagia. For an objective evaluation of decannulation readiness the "Standardized Endoscopic Swallowing Evaluation for Tracheostomy Decannulation in Critically Ill Neurologic Patients" (SESETD) - a stepwise evaluation of 'secretion management', 'spontaneous swallows' and 'laryngeal sensibility/cough' - has been introduced. With the recent study detailed data on inter-rater and test-retest reliability are presented.

Methods

To obtain inter-rater reliability levels both in a group of raters with at least 5 years of experience ('experts') and in a group of raters with no or only minor experience using the SESETD ('non-experts'), for each single item of the protocol and the sum score α-, respectively κ-levels were determined. The 'experts' assessed the same videos after a four-week interval to determine test-retest reliability. Ten videos from tracheostomized neurological patients completely weaned from mechanical ventilation were assessed independently by six 'experts'. 27 'non-experts' applied the SESETD on 5 videos from the same patient population after introduction to the protocol in a one-hour workshop.

Results

For the items 'secretion management' and 'spontaneous swallows' α-levels were identified at > 0.800 both in the group of 'experts' and 'non-experts'. With regard to the item 'laryngeal sensibility/cough' in both groups, the α-level was ≥0.667. With κ-levels of 1.0 for 'secretion management', 0.93 for 'spontaneous swallows' and 0.76 for 'laryngeal sensibility/cough' test-retest reliability showed at least substantial agreement for each item. Intraclass correlation coefficient for the sum score was excellent in both groups (α ≥ 0.90).

Conclusions

The SESETD demonstrates good to excellent agreement for each single item included as well as the sum score in experienced and unexperienced raters supporting its usefulness for implementation in daily clinical routine and as an outcome measure for clinical trials.

Fiberoptic Endoscopic Evaluation of Swallowing in Infants and Children: Protocol, Safety, and Clinical Efficacy: 25 Years of Experience

BACKGROUND

The application of fiberoptic endoscopic evaluation of swallowing (FEES) in the pediatric dysphagia protocol requires specialized knowledge of pediatric conditions that result in dysphagia, recognition of normal and abnormal laryngopharyngeal anatomy and function across ages, and the ability to identify maturational changes in anatomy and function of the aerodigestive tract that pertain to airway protection and swallowing function.

METHODS

Over the past 25 years, we have performed over 7,000 collaborative Otolaryngology and Speech-Language Pathology FEES examinations in patients ranging from 2 days of age to young adults. During this time period, we have monitored the safety of the procedure, explored the feasibility and utility of FEES across conditions, compared and contrasted FEES to the videofluoroscopic evaluation of swallowing (VFSS), and developed specific pediatric FEES protocols with operational definitions for identification and interpretation of swallowing parameters.

RESULTS

FEES has proved to be a safe procedure in patients across ages. There have been no significant adverse events. FEES is comparable to the VFSS in the assessment of events before and after the swallow. It provides unique information regarding laryngopharyngeal anatomy and function, airway protection integrity, sensory threshold, and secretion management ability, as well as pharyngeal swallowing dynamics and the efficacy of compensatory swallowing strategies.

CONCLUSIONS

There are specific indications and contraindications for pediatric FEES, and unique components that characterize the pediatric FEES protocols across ages and conditions. FEES procedures performed jointly by an Otolaryngologist and Speech-Language pathologist offer a team approach to interpretation and management recommendations.

Effects of Smoking Exposure in Infants on Gastroesophageal Reflux as a Function of the Sleep-Wakefulness State

OBJECTIVE

To determine whether perinatal smoking exposure is associated with gastroesophageal reflux (GER)-related changes in sleep-wakefulness states in neonates.

STUDY DESIGN

Thirty-one neonates, referred for the investigation of suspected GER, were recruited and underwent multichannel impedance-pH monitoring and synchronized 8- to 12-hour polysomnography. The infants' exposure to tobacco smoke was estimated by means of a urine cotinine assay. The total number, frequency (h^-1), and mean duration (minutes) of GER-pH (reflux events detected by the pH electrode only) and GER-imp (reflux events with bolus movement detected by impedance) events were determined. Intergroup differences (smoking-exposed group vs nonexposed group) were probed with nonparametric, unpaired Mann-Whitney U tests. A χ² test was used to assess a possible intergroup difference in bolus retrograde migration during GER-imp events.

RESULTS

According to the urine cotinine assay, 21 of the 31 neonates had been exposed to cigarette smoke during the perinatal period. The number (and frequency) of GER-imp was significantly greater (P = .016) in the exposed group (29 [0-90]) than in the nonexposed group (12 [2-35]). Migration of the esophageal bolus from the distal segment to the most proximal segment was significantly more frequent (P = .016) in the exposed group (83% of GER) than in the nonexposed group (41%). The GER pattern associated with smoking exposure was particularly obvious during Rapid eye movement sleep.

CONCLUSIONS

The more frequent occurrence and greater proximal migration of GER-imp in the smoking-exposed group (especially during rapid eye movement sleep) may have clinical relevance. Smoking exposure is a preventable risk factor for limiting the occurrence of GER in neonates.

Gastroesophageal Reflux Disease Might Induce Certain-Supposedly Adaptive-Changes in the Esophagus: A Hypothesis

BACKGROUND

The increasing prevalence of GERD has become a major concern due to its major health and economic impacts. Beyond the typical unpleasant symptoms, reflux can also be the source of severe, potentially life-threatening complications, such as aspiration.

AIM

Our aim was to support our hypothesis that the human body may in some cases develop various protective mechanisms to prevent these conditions.

METHODS

Based on our experiences and review of the literature, we investigated the potential adaptive nature of seven reflux complications (hypertensive lower esophageal sphincter, achalasia, hypertensive upper esophageal sphincter, Zenker's diverticulum, Schatzki's ring, esophageal web, and Barrett's esophagus).

RESULTS

Patients with progressive GERD may develop diverse structural and functional esophageal changes that narrow the lumen of the esophagus and therefore reduce the risk of regurgitation and protect the upper aerodigestive tract from aspiration. The functional changes (hypertensive lower esophageal sphincter, achalasia, hypertensive upper esophageal sphincter) seem to be adaptive reactions aimed at easing the unpleasant symptoms and reducing acid regurgitation. The structural changes (Schatzki's ring, esophageal web) result in very similar outcomes, but we consider these are rather secondary consequences and not real adaptive mechanisms. Barrett's esophagus is a special form of adaptive protection. In these cases, patients report significant relief of their previous heartburn as Barrett's esophagus develops because of the replacement of the normal squamous epithelium of the esophagus by acid-resistant metaplastic epithelium.

CONCLUSION

We believe that GERD may induce different self-protective reactions in the esophagus that result in reduced acid regurgitation or decreased reflux symptoms.

Defining pharyngeal contractile integral during high-resolution manometry in neonates: a neuromotor marker of pharyngeal vigor

BACKGROUND

Pharyngeal contractility is critical for safe bolus propulsion. Pharyngeal contractile vigor can be measured by Pharyngeal Contractile Integral (PhCI): product of mean pharyngeal contractile amplitude, length, and duration. We characterized PhCI in neonates and examined the hypothesis that PhCI differs with mode of stimulation.

METHODS

Nineteen neonates born at 38.6 (34-41) weeks gestation were evaluated at 42.9 (40.4-44.0) weeks postmenstrual age using high-resolution manometry (HRM). PhCI was calculated using: (a) Conventional and (b) Automated Swallow Detection algorithm (ASDA) methods. Contractility metrics of all pharyngeal regions were examined using mixed statistical models during spontaneous and adaptive state (pharyngeal and oral stimulus) swallowing.

RESULTS

PhCI of oral stimuli swallows were distinct from pharyngeal stimuli and spontaneous swallows (P < 0.05). Correlation between conventional and ASDA methods was high (P < 0.001). PhCI increased with swallows for pharyngeal stimulation (P < 0.05) but remained stable for swallows with oral stimulation. PhCI differed between proximal and distal pharynx (P < 0.001).

CONCLUSIONS

PhCI is a novel reliable metric capable of distinguishing (1) proximal and distal pharyngeal activity, (2) effects of oral and pharyngeal stimulation, and (3) effects of prolonged stimulation. Changes in pharyngeal contractility with maturation, disease, and therapies can be examined with PhCI.

Aspiration Pneumonia and Related Syndromes

Aspiration is a syndrome with variable respiratory manifestations that span acute, life-threatening illnesses, such as acute respiratory distress syndrome, to chronic, sometimes insidious, respiratory disorders such as aspiration bronchiolitis. Diagnostic testing is limited by the insensitivity of histologic testing, and although gastric biomarkers for aspiration are increasingly available, none have been clinically validated. The leading mechanism for microaspiration is thought to be gastroesophageal reflux disease, largely driven by the increased prevalence of gastroesophageal reflux across a variety of respiratory disorders, including chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis, and chronic cough. Failure of therapies targeting gastric acidity in clinical trials, in addition to increasing concerns about both the overuse of and adverse events associated with proton pump inhibitors, raise questions about the precise mechanism and causal link between gastroesophageal reflux and respiratory disease. Our review summarizes key aspiration syndromes with a focus on reflux-mediated aspiration and highlights the need for additional mechanistic studies to find more effective therapies for aspiration syndromes.

Achalasia following reflux disease: coincidence, consequence, or accommodation? An experience-based literature review

Achalasia is a motility disorder of the esophagus characterized by the defective peristaltic activity of the esophageal body and impaired relaxation of the lower esophageal sphincter due to the degeneration of the inhibitory neurons in the myenteric plexus of the esophageal wall. The histopathological and pathophysiological changes in achalasia have been well described. However, the exact etiological factors leading to the disease still remain unclear. Currently, achalasia is believed to be a multifactorial disease, involving both extrinsic and intrinsic factors. Based on our experience and the review of literature, we believe that gastroesophageal reflux disease (GERD) might be one of the triggering factors leading to the development of achalasia. However, it is also stated that the two diseases can simultaneously appear independently from each other. Considering the large number and routine treatment of patients with GERD and achalasia, the rare combination of the two may even remain unnoticed; thus, the analysis of larger patient groups with this entity is not feasible. In this context, we report four cases where long-standing reflux symptoms preceded the development of achalasia. A literature review of the available data is also given. We hypothesize that achalasia following the chronic acid exposure of the esophagus is not accidental but either a consequence of a chronic inflammation or a protective reaction of the organism in order to prevent aspiration and lessen reflux-related symptoms. This hypothesis awaits further clinical confirmation.

Upper esophageal sphincter augmentation reduces pharyngeal reflux in nasogastric tube-fed patients

OBJECTIVES/HYPOTHESIS

Aspiration of gastric refluxate is one of the most commonly observed complications among long-term nasogastric tube (NGT) fed patients. The upper esophageal sphincter (UES) pressure barrier is the main defense mechanism against pharyngeal reflux of gastric contents. Our objective was to investigate the efficacy and safety of the UES assist device (UES-AD) in preventing gastric reflux through the UES in long-term NGT-fed patients.

STUDY DESIGN

Self-Controlled Case series.

METHODS

We studied 10 patients (mean age = 90.6 ± 3.4 years, four females) with dysphagia caused by stroke or dementia who were fed for 0.5 to 5 years (median = 3 years) by NGT. External pressures of 20 to 30 mm Hg were applied by using a handmade UES-AD, which was started 2 hours after the beginning of NGT infusion and was alternated between periods of 2 hours on and 2 hours off, for a total of 12 hours. Placement of the impedance sensors within the UES was guided by high-resolution manometry. Trans-UES and intraesophageal reflux events were recorded by using 24-hour combined pH-impedance measurements.

RESULTS

No aspiration pneumonia events were noted in the period 1 month before or during the study in any of the cohort. Baseline UES pressure averaged 17.5 ± 9.4 mm Hg and was increased to 38.9 ± 11.9mm Hg after application of the UES-AD. Overall frequency of trans-UES reflux decreased significantly with the UES-AD compared to without (0.8 ± 0.9 vs. 3.3 ± 2.8, P < .05 for the 12-hour study period). There was no effect of the UES-AD on esophageal reflux events (7.4 ± 4.4 vs. 6.4 ± 3.0, P > .05).

CONCLUSIONS

UES-AD significantly decreases the number of trans-UES reflux events and can potentially reduce the aspiration risk associated with NGT feeding.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1310-1315, 2018.

Maturation Modulates Pharyngeal-Stimulus Provoked Pharyngeal and Respiratory Rhythms in Human Infants

Pharyngeal-provocation induced aerodigestive symptoms in infants remain an enigma. Sources of pharyngeal provocation can be anterograde as with feeding, and retrograde as in gastroesophageal reflux. We determined maturational and dose-response effects of targeted pharyngeal-stimulus on frequency, stability, and magnitude of pharyngeal and respiratory waveforms during multiple pharyngeal swallowing responses in preterm-born infants when they were of full-term postmenstrual age (PMA). Eighteen infants (11 male) were studied longitudinally at 39.8 ± 4.8 weeks PMA (time-1) and 44.1 ± 5.8 weeks PMA (time-2). Infants underwent concurrent pharyngo-esophageal manometry, respiratory inductance plethysmography, and nasal airflow thermistor methods to test sensory-motor interactions between the pharynx, esophagus, and airway. Linear mixed models were used and data presented as mean ± SEM or %. Overall, responses to 250 stimuli were analyzed. Of the multiple pharyngeal swallowing responses (n = 160), with maturation (a) deglutition apnea duration decreases (p < 0.01), (b) number of pharyngeal waveform peaks and duration decreases for initial responses (p < 0.01), and subsequent responses have lesser variation and greater stability (p < 0.01). With increment in stimulus volumes we noted (a) increased prevalence (%) of pharyngeal responses (p < 0.05), (b) increased number of pharyngeal peaks (p < 0.05), yet pharyngeal frequency (Hz), variability, and stability remain unaffected (p > 0.05), and (c) respiratory changes were unaffected (p > 0.05). Initial and subsequent pharyngeal responses and respiratory rhythm interactions become more distinct with maturation. Interval oromotor experiences and volume-dependent increase in adaptive responses may be contributory. These mechanisms may be important in modulating and restoring respiratory rhythm normalcy.

Spontaneous swallow frequency compared with clinical screening in the identification of dysphagia in acute stroke

BACKGROUND

The aim of this study was to compare spontaneous swallow frequency analysis (SFA) with clinical screening protocols for identification of dysphagia in acute stroke.

METHODS

In all, 62 patients with acute stroke were evaluated for spontaneous swallow frequency rates using a validated acoustic analysis technique. Independent of SFA, these same patients received a routine nurse-administered clinical dysphagia screening as part of standard stroke care. Both screening tools were compared against a validated clinical assessment of dysphagia for acute stroke. In addition, psychometric properties of SFA were compared against published, validated clinical screening protocols.

RESULTS

Spontaneous SFA differentiates patients with versus without dysphagia after acute stroke. Using a previously identified cut point based on swallows per minute, spontaneous SFA demonstrated superior ability to identify dysphagia cases compared with a nurse-administered clinical screening tool. In addition, spontaneous SFA demonstrated equal or superior psychometric properties to 4 validated, published clinical dysphagia screening tools.

CONCLUSIONS

Spontaneous SFA has high potential to identify dysphagia in acute stroke with psychometric properties equal or superior to clinical screening protocols.

Aspiration Induced by Remifentanil

Background:

Remifentanil is widely used for monitored anesthesia care in spontaneously breathing patients. However, the authors’ previous studies have shown that remifentanil induces subjective swallowing difficulties, which may increase the risk of aspiration.

Methods:

Twenty-five healthy volunteers participated in a double-blind, randomized, crossover trial at the University Hospital in Örebro, Örebro, Sweden. The volunteers were studied on two different occasions during which they received either remifentanil with an effect-site target concentration of 3 ng/ml or saline over 1 h. A radionuclide tracer was infused simultaneously into the nasopharynx at a rate of 0.1 ml/min. Aspiration was determined by lung scans, and subjective swallowing difficulties and grip strength were evaluated. The primary outcome was the difference in occurrence of aspiration between remifentanil and placebo treatments. The secondary outcomes were differences in swallowing difficulty and grip strength and the association between aspiration and swallowing difficulty.

Results:

During remifentanil and placebo infusion, 48 and 12% of the volunteers aspirated, respectively, difference: 36% (95% CI, 10 to 62%). A similar significant difference was found for swallowing difficulties but not for the association between aspiration and swallowing. No difference was found in grip strength between the two treatments.

Conclusions:

Remifentanil infusion at concentrations used in monitored anesthesia care increases the incidence of aspiration. However, the subjective swallowing difficulty induced by remifentanil is not indicative of the aspiration risk.

Effect of aging on hypopharyngeal safe volume and the aerodigestive reflexes protecting the airways

OBJECTIVES/HYPOTHESIS

Studies on young volunteers have shown that aerodigestive reflexes are triggered before the maximum volume of fluid that can safely collect in the hypopharynx before spilling into the larynx is exceeded (hypopharyngeal safe volume [HPSV]). The objective of this study was to determine the influence of aging on HPSV and pharyngo-glottal closure reflex (PGCR), pharyngo-UES contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS).

STUDY DESIGN

Comparison between two groups of different age ranges.

METHODS

Ten young (25 ± 3 standard deviation [SD] years) and 10 elderly (77 ± 3 SD years) subjects were studied. PGCR, PUCR, and RPS were elicited by perfusing water into the pharynx rapidly and slowly. HPSV was determined by abolishing RPS with pharyngeal anesthesia.

RESULTS

Frequency-elicitation of PGCR and PUCR were significantly lower in the elderly compared to the young during slow water perfusion (47% vs. 97% and 40% vs. 90%, respectively, P < .001). RPS was absent in five of the 30 (17%) slow injections in the elderly group. In these elderly subjects, HPSV was exceeded and laryngeal penetration of the water was seen. The threshold volume to elicit PGCR, PUCR, and RPS was significantly lower than the HPSV during rapid injections. Except for RPS, these volumes were also significantly lower than HPSV during slow injections.

CONCLUSIONS

PGCR, PUCR, and RPS reflexes are triggered at a threshold volume significantly lower than the HPSV in both young and elderly subjects. Lower frequency-elicitation of PGCR, PUCR, and RPS in the elderly can predispose them to the risks of aspiration.

Spontaneous swallowing frequency has potential to identify dysphagia in acute stroke

BACKGROUND AND PURPOSE

Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke.

METHODS

In a cohort of 63 acute stroke cases, swallow frequency rates (swallows per minute [SPM]) were compared with stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with versus without clinically significant dysphagia. Receiver operating characteristic curve analysis was used to identify the optimal threshold in SPM, which was compared with a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was used to identify the minimally adequate time period to complete spontaneous swallow frequency analysis.

RESULTS

SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. Receiver operating characteristic curve analysis yielded a threshold of SPM≤0.40 that identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5- to 10-minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke.

CONCLUSIONS

Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel.

Effects of postnatal environmental tobacco smoke on non-nutritive swallowing-breathing coordination in newborn lambs

While prenatal environmental tobacco smoke (ETS) exposure is a well-known risk factor for sudden infant death syndrome, the effect of postnatal ETS exposure is less clear. The objective of this study was to investigate the effect of postnatal ETS exposure on non-nutritive swallowing (NNS) and NNS-breathing coordination, which are crucial to prevent aspiration related-cardiorespiratory events. Eighteen newborn lambs (6 per group) were randomly exposed to either 10 cigarettes/day, 20 cigarettes/day or room air for 15 days. Lambs were instrumented for recording states of alertness, swallowing, electrocardiogram and breathing; recordings were performed in non-sedated lambs at the end of ETS exposure. Urinary cotinine/creatinine ratio confirmed relevant real-life exposure. Postnatal ETS exposure had no effect on NNS frequency but tended to decrease inspiratory NNS (p=0.07) during quiet sleep. No effect on respiratory or heart rate (p>0.6), apnea index (p=0.2) or sleep states (p=0.3) was observed. In conclusion, postnatal ETS exposure in lambs had only mild effects on NNS-breathing coordination.

Validation and demonstration of an isolated acoustic recording technique to estimate spontaneous swallow frequency

Spontaneous swallowing is considered a reflexive, pharyngeal clearance mechanism. Reductions in spontaneous swallow frequency may be a sensitive index for dysphagia and related morbidities. This study evaluated an acoustic recording technique as a measure to estimate spontaneous swallow frequency. Initially, a multichannel physiologic (surface electromyography, swallow apnea, cervical auscultation) recording technique was validated and subsequently compared to an isolated acoustic (microphone) recording technique on a sample of younger (25 ± 2.8 years) and older (68 ± 5.3 years) healthy adult participants. Sensitivity (94 %), specificity (99 %), and classification accuracy (98 %) were high for swallow identification from the multichannel physiologic recording technique. Interjudge reliability was high (k = 0.94, 95 % CI = 0.92-0.96). No significant differences in spontaneous swallow frequency were observed between the multichannel physiologic recordings and the acoustic recordings (0.85 vs. 0.81 swallows per minute). Furthermore, these two techniques were highly correlated (r = 0.95). Interjudge reliability for swallow identification via acoustic recordings was high (k = 0.96, 95 % CI = 0.94-0.99). Preliminary evaluation of the temporal stability of spontaneous swallow frequency measured from acoustic recordings indicated that time samples as short as 5 min produce viable results. Age differences were identified in spontaneous swallow frequency rates, with older participants swallowing less frequently than younger participants (0.47 vs. 1.02 swallows per minute). Collectively, these results indicate that an isolated acoustic recording technique is a valid approach to estimate spontaneous swallow frequency.

Pharyngeal dysphagia in inflammatory muscle diseases resulting from impaired suprahyoid musculature

Dysphagia has previously been reported in the inflammatory myopathies (IMs): inclusion body myositis (IBM), dermatomyositis (DM), and polymyositis (PM). Patients report coughing, choking, and bolus sticking in the pharynx. Myotomy has been the treatment of choice, with variable success reported. We sought to determine underlying causes of dysphagia in IM patients using instrumental evaluation. Eighteen subjects participated in the study: four with DM, six with PM, and eight with IBM. They underwent simultaneous videofluoroscopy and manometry, yielding 214 swallows for analysis regarding function of the upper esophageal sphincter (UES), swallow initiation, hyolaryngeal excursion, and pharyngeal residue. Penetration and aspiration were also recorded. UES failed to relax in two participants. High incidence of pharyngeal dysphagia was noted; 72% of participants demonstrated abnormalities, including delayed swallow initiation (24%), decreased hyolaryngeal excursion (22%), pyriform residue (17%), and penetration (22%). Dysphagia in IM patients appears to be more due to impaired muscle contraction and reduced hyolaryngeal excursion than the often held belief of failed UES relaxation. The distinction between mechanisms causing patients' dysphagia should be examined, particularly if CP myotomy is being considered as it may be contraindicated for patients with normal UES relaxation. More studies investigating IM patients pre- and post-myotomy are needed.