Effect of chronic and acute cigarette smoking on the pharyngoglottal closure reflex

Swallowing dysfunction between the community-living older adults with and without comorbid conditions using Patient-Reported Outcome Measures (PROM)

OBJECTIVE

The present study aimed to investigate older adults' perspective on their swallowing physiology using a PROM tool. The study further explored the swallowing issues among older adults with and without comorbid conditions.

METHOD

One hundred twenty-two (122) participants participated in the e-survey. A questionnaire was developed to assess the swallowing deficits among older adults, and Eating Assessment Tool-10 (EAT-10) was administered to assess the PROM.

RESULTS

The results revealed that 40% of older adults with comorbid conditions had EAT-10 scores greater than 3, suggesting swallowing deficits. A significant difference was observed between the two groups with respect to swallowing deficits, as reported on EAT-10.

CONCLUSION

Based on the results, it can be delineated that swallowing deficits emerge with aging. More of older adults with comorbid conditions reported swallowing deficits in comparison to those without comorbid conditions. Hence, their nutritional and health status gets compromised, leading to poor quality of life.

Prevalence, Incidence, and Predictors of Self-reported Swallowing Difficulties in Community-Dwelling Adults: A Population-Based Study from the Canadian Longitudinal Study on Aging (CLSA)

There is a paucity of evidence from population-based studies identifying prevalence and incidence of dysphagia, as well as health and sociodemographic risk factors that may contribute to its development. As such, the current study aimed to determine prevalence, incidence, and associated predictors of dysphagia in adults. The Canadian Longitudinal Study on Aging is a nationally representative population study that follows 51,338 Canadians over 45 years of age. Biological, medical, psychological, social, lifestyle and economic data are collected. A secondary analysis of the data was conducted to determine prevalence, incidence, and the predictors of self-reported swallowing difficulty in adults between 45 and 85 years of age. Rates of swallowing difficulty by demographic risk factor, as well as lifestyle and health factors were analyzed using descriptive statistics. Associations between lifestyle and health variables with dysphagia were tested using Chi-square tests or t tests, as appropriate. Logistic regression was used to determine the predictors of self-reported swallowing difficulties. Overall prevalence of self-reported swallowing difficulties in adults over the age of 45 was 10.6% and increased to 13.7% after 3 years. Significant differences (p < 0.001) in self-reported swallowing difficulty at baseline were apparent across smoking status, requiring help to prepare meals, life satisfaction, social participation, all disease categories except dementia, number of medications, cognition, oral health status, and frailty. Incidence of dysphagia was 8.6%. Regression analyses suggested the following independent predictors of reports of swallowing difficulty: older age; non-white ethnicity; female sex; poor oral health; malnutrition; and frailty. These predictors should be carefully considered to ensure we are screening at-risk populations. Social determinants of health, such as ethnicity, must also be considered to ensure equitable care across the population.

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.

Risk factors for aspiration pneumonia in patients with dysphagia undergoing videofluoroscopic swallowing studies: A retrospective cohort study

Prediction of aspiration pneumonia development in at-risk patients is vital for implementation of appropriate interventions to reduce morbidity and mortality. Unfortunately, studies utilizing a comprehensive approach to risk assessment are still lacking. The objective of this study was to analyze the clinical features and videofluoroscopic swallowing study (VFSS) findings that predict aspiration pneumonia in patients with suspected dysphagia.Medical records of 916 patients who underwent VFSS between September 2014 and June 2018 were retrospectively analyzed. Patients were divided into either a pneumonia group or a non-pneumonia group based on diagnosis of aspiration pneumonia. Clinical information and VFSS findings were evaluated.One hundred seven patients (11.7%) were classified as having pneumonia. Multivariate analysis indicated that aspiration during the 2- cubic centimeter thick-liquid trial of VFSS (odds ratio [OR] = 3.23, 95% confidence interval [CI]: 1.93-5.41), smoking history (OR = 2.63, 95% CI: 1.53-4.53), underweight status (OR = 2.27, 95% CI: 1.31-3.94), abnormal pharyngeal delay time (OR = 1.60, 95% CI: 1.01-2.53), and a Penetration-Aspiration Scale level of 8 (OR = 3.73, 95% CI: 2.11-6.59) were significantly associated with aspiration pneumonia development. Integrated together, these factors were used to develop a predictive model for development of aspiration pneumonia (DAP), with a sensitivity of 82%, specificity of 56%, and an area under the receiver operating characteristic curve of 0.73.The best predictors for DAP included videofluoroscopic findings of aspiration during a 2-cubic centimeter thick-liquid trial, prolonged pharyngeal delay time, a Penetration-Aspiration Scale level of 8, history of smoking, and underweight status. These 5 proposed determinants and the associated DAP score are relatively simple to assess and may constitute a clinical screening tool that can readily identify and improve the management of patients at risk for aspiration pneumonia.

Using Wearable and Non-Invasive Sensors to Measure Swallowing Function: Detection, Verification, and Clinical Application

BACKGROUND

A widely used method for assessing swallowing dysfunction is the videofluoroscopic swallow study (VFSS) examination. However, this method has a risk of radiation exposure. Therefore, using wearable, non-invasive and radiation-free sensors to assess swallowing function has become a research trend. This study addresses the use of a surface electromyography sensor, a nasal airflow sensor, and a force sensing resistor sensor to monitor the coordination of respiration and larynx movement which are considered the major indicators of the swallowing function. The demand for an autodetection program that identifies the swallowing patterns from multiple sensors is raised. The main goal of this study is to show that the sensor-based measurement using the proposed detection program is able to detect early-stage swallowing disorders, which specifically, are useful for the assessment of the coordination between swallowing and respiration.

METHODS

Three sensors were used to collect the signals from submental muscle, nasal cavity, and thyroid cartilage, respectively, during swallowing. An analytic swallowing model was proposed based on these sensors. A set of temporal parameters related to the swallowing events in this model were defined and measured by an autodetection algorithm. The verification of this algorithm was accomplished by comparing the results from the sensors with the results from the VFSS. A clinical application of the long-term smoking effect on the swallowing function was detected by the proposed sensors and the program.

RESULTS

The verification results showed that the swallowing patterns obtained from the sensors strongly correlated with the laryngeal movement monitored from the VFSS. The temporal parameters measured from these two methods had insignificant delays which were all smaller than 0.03 s. In the smoking effect application, this study showed that the differences between the swallowing function of smoking and nonsmoking participants, as well as their disorders, is revealed by the sensor-based method without the VFSS examination.

CONCLUSIONS

This study showed that the sensor-based non-invasive measurement with the proposed detection algorithm is a viable method for temporal parameter measurement of the swallowing function.

Otorhinolaryngological symptoms among smokeless tobacco (Maras powder) users

OBJECTIVE:

This study aims to investigate the relationship between smokeless tobacco (maras powder) consumption and otorhinolaryngological symptoms.

METHODS:

This descriptive study was carried out on 599 participants. The participants were divided into two groups. Of these, 299 (49.9%) patients aged over 18 years were the first group; they used smokeless tobacco for at least 5 years. The remaining patients comprised the second group, which included 300 (50.1%) healthy volunteers who did not use tobacco or its products and demonstrated some similarities with the first group. For the purpose of data collection, a questionnaire consisting of 45 questions was administered to the participants.

RESULTS:

Cough, sputum, shortness of breath, dysphagia, snoring, and apnea-hypopnea were found to be significantly increased in smokeless tobacco users. The highest odds ratio (OR) found was for sputum at 2.615. Similarly, other oral cavity symptoms such as mouth tickling, dryness of throat, mouth sores, halitosis, taste disorders, and toothache were found to be significantly increased in smokeless tobacco users. It is noteworthy that halitosis was 9.4 times more prevalent among smokeless tobacco users than in the non-tobacco users. Sinonasal symptoms such as sneezing, headache, facial fullness, and anorexia were found to be significantly increased in smokeless tobacco users. However, there were no differences between the groups in terms of ear symptoms.

CONCLUSION:

This study demonstrated that the negative effects of smokeless tobacco consumption were particularly higher in the oral cavity, which in turn gave rise to a number of serious upper respiratory tract complaints.

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.

Analysis of cigarette smoking mechanism by real time video-endoscopic documentation

OBJECTIVE

To view, document and analyze the smoking mechanism as seen via video-endoscopic examination during the action of cigarette smoking.

STUDY DESIGN

Observational study.

METHODS

Twenty-two healthy smoking volunteers were examined with a trans-nasal video-laryngoscope while breathing, sniffing and cigarette smoking. Smoking a whole cigarette was recorded in each participant. The different stages of smoking were defined and their duration was measured. The glottic opening angle was calculated during breathing, sniffing and smoking.

RESULTS

A smoking cycle with four distinct stages was recognized. The stages included an oral smoke accumulation, pharyngo-laryngeal jet inhalation, infralaryngeal spread, and finally humidified exhalation stage. The stages' mean duration was 1.93(±1.21), 0.39(±0.31), 2.00(±1.12) and 4.5(±2.70) seconds, respectively. The glottic opening angle during smoke inhalation was wider in 16% (p = 0.02) compared to normal inhalation during breathing. The glottic opening during smoke exhalation was comparable to what was observed during normal exhalation. The reduction in the glottic opening was more significant during the action of smoking compared with normal breathing (p = 0.042).

CONCLUSIONS

Smoking follows a consistent sequence of events, defined by specific anatomic configuration and relatively persistent duration. The fast turbulent flow of the smoke over the narrow glottic aperture and at the areas of bifurcation at the trachea and bronchi may have a role in the high relative risk for carcinoma in these areas.

Association between Chronic Laryngitis and Particulate Matter Based on the Korea National Health and Nutrition Examination Survey 2008-2012

Background

Chronic laryngitis (CL) has been described as chronic inflammation of the larynx. CL have various causes such as long-term smoking, acid reflux, voice overuse, bronchitis, allergies, pneumonia, excessive exposure to toxic chemicals and complications from the flu or a chronic cold. However, the prevalence of CL and role of air pollution in the etiology is uncertain.

Objective

The aim of this study was to investigate the relationship between CL and particulate matter with aerodynamic diameter less than 10 μm (PM₁₀) in South Korea using data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2008–2012.

Methods

KNHANES is a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 21,116). A field survey team that included an otolaryngologist moved with a mobile examination unit and performed interviews and physical examinations. The mean annual concentrations of ambient PM10, SO2, O3, NO2, and CO levels in Korea were determined from monitoring station data. Multiple logistic regression was used to examine the relationship of air pollution to CL.

Results

Among the population ≥ 19 years of age, the weighted prevalence of CL was 3.37 ± 0.30% (95% confidence interval, 2.79–3.95%). CL was more prevalent in men, current smokers, and those with lower household income and prevalence increased with age. A significant decrease over time was observed in the prevalence of CL (P for trend = 0.0049) and the annual average concentrations of PM₁₀ (P for trend < 0.0001) from 2008 to 2012. In a multivariate model, the factors associated with CL included PM₁₀ (odds ratio [OR], 1.378, p = 0.0457), age (OR, 1.020, p<0.0001), sex (OR, 0.734, p = 0.0179), and smoking status (OR, 1.438, p = 0.0054).

Conclusion

Elevated PM10 exposures could be associated with increased risk of CL in South Koreans. Further epidemiological and experimental studies are necessary to clarify the impact of chronic PM₁₀ exposure on CL.

Gastroesophageal reflux symptoms in Turkish people: a positive correlation with abdominal obesity in women

OBJECTIVE:

Metabolic syndrome (MetS) is increasing around the world due to abdominal obesity with altered eating habits and decreased physical activity. The aim of this study was to determine the risk factors for gastroesophagial reflux disease (GERD) symptoms and the prevalence of GERD in patients with MetS.

METHODS:

Five hundred patients (MetS, n=300 and the control group, n=200) were enrolled in the study. A detailed questionnaire reflux symptoms and behavioral habits was performed.

RESULTS:

Sixty percent of the subjects were with MetS. GERD rate was significantly higher in the group with MetS compared to subjects without MetS (50.7% vs 26%). Women were more likely to have GERD in both groups (62.6% of women and 28.6% of men ın the MetS group while corresponding rates were 37% vs 16.7% in the control group). Waist circumferences were found to be higher in female MetS patients with GERD.

CONCLUSION:

GERD is present approximately in every one of the two patients with MetS. Every patient who has MetS should be evaluated in terms of GERD symptoms.

Association between Obesity and Chronic Laryngitis in Women--Data from the Korea National Health and Nutrition Examination Survey

BACKGROUND

This study aimed to investigate the relationship between obesity and chronic laryngitis in South Korea using data from the Korea National Health and Nutrition Examination Surveys (KNHANES) collected during 2008-2010.

METHODS

KNHANES was a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 13,819). Obesity status was measured by using BMI and waist circumference.

RESULTS

Among the population over 19 years of age, the prevalence of chronic laryngitis was 4.0 ± 0.4%. Chronic laryngitis was significantly associated with age, BMI, waist circumference, fat proportion, both systolic and diastolic blood pressure, fasting blood sugar, triglycerides, and high-density lipoprotein cholesterol in women. Old age and current smoking were significantly associated with chronic laryngitis in men. Obese women were at a higher risk for chronic laryngitis than women without obesity (odds ratio (OR) 2.022, 95% confidence interval (95% CI) 1.412-2.895) after further adjustment for confounders. Women with abdominal obesity were also at higher risk for chronic laryngitis (OR 1.475, 95% CI 1.024-2.126).

CONCLUSION

Obese women in Korea have an elevated risk for developing chronic laryngitis. Further epidemiological and experimental studies are necessary to clarify the impact of obesity on this condition.

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.

Characterization of the upper esophageal sphincter response during cough

BACKGROUND

Vagal reflex initiated by esophageal stimulation and microaspiration can cause chronic cough in patients with gastroesophageal reflux disease (GERD). By raising intraabdominal pressure,cough can, in turn, predispose to GERD. The role of the upper esophageal sphincter (UES)in preventing esophagopharyngeal reflux during coughing is not well known. The aim of this study was to evaluate the UES response during coughing.

METHODS

We studied 20 healthy young (10 women; age, 27 ± 5 years) and 15 healthy elderly(nine women; age, 73 ± 4 years) subjects. Hard and soft cough-induced pressure changes in the UES, distal esophagus, lower esophageal sphincter, and stomach were determined simultaneously using high-resolution manometry and concurrent acoustic cough recordings.

RESULTS

Resting UES pressure was significantly higher in the young compared with the elderly subjects (42 ± 14 mm Hg vs 24 ± 9 mm Hg; P < .001). Cough induced a UES contractile response in all subjects. Despite lower UES resting pressures in the elderly subjects, the maximum UES pressure during cough was similar between the young and the elderly subjects (hard cough, 230 ± 107 mm Hg vs 278 ± 125 mm Hg, respectively; soft cough, 156 ± 85 mm Hg vs 164 ± 119 mm Hg, respectively; P not significant for both). The UES pressure increase over baseline during cough was significantly higher than that in the esophagus, lower esophageal sphincter, and stomach for both groups ( P < .001).

CONCLUSIONS

Cough induces a rise in UES pressure, and this response is preserved in elderly people. A cough-induced rise in UES pressure is significantly higher than that in the esophagus and stomach,thereby providing a barrier against retrograde entry of gastric contents into the pharynx.

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.

Is aspiration during swallowing more common in Canadian children with indigenous heritage?

While many factors that contribute to the occurrence of lower respiratory tract infections (LRTI) in Canadian indigenous children have been described, the role of aspiration during swallowing has not been explored in these children. Because of an increase in referrals of indigenous children from our catchment area (Manitoba, North Western Ontario, and Nunavut) for assessment of aspiration during swallowing, we retrospectively reviewed the clinical records of 325 consecutive children undergoing videofluoroscopic swallowing studies (VFSS) to evaluate which factors, including indigenous heritage and LRTI, were associated with aspiration during swallowing. Our sample had an overrepresentation of indigenous children (35% compared to 23% in the catchment area). These children were more likely to aspirate during swallowing (P = 0.001) and to have experienced an LRTI prior to the VFSS (P = 0.000). When separating the children who aspirated into two groups based on indigenous heritage, the indigenous children were more likely to have had an LRTI (P = 0.028) than the other children in the sample. With logistic regression analysis, significant correlations between indigenous heritage, LRTI (P = 0.000), and aspiration (P = 0.009) were found. When aspiration during swallowing was the factor of interest, it correlated with both LRTI (P = 0.001) and the presence of congested upper airway noises after eating (P = 0.000). These upper airway noises were strongly associated with aspiration in indigenous children (P = 0.004). While prospective data are required to determine if the correlations seen in this retrospective review will remain robust, indigenous children were more likely to aspirate during swallowing and have LRTI in this sample. Whether aspiration during swallowing is related to environmental, ethnic, or biological factors in indigenous children remains to be determined, but the association between aspiration and congested upper airway noises after eating may assist in the early diagnosis of aspiration during swallowing, and thereby enable timely intervention to decrease aspiration risk in children already at risk of repeated LRTI due to a number of other confounding factors.

Pharyngeal airway protective reflexes are triggered before the maximum volume of fluid that the hypopharynx can safely hold is exceeded

Aerodigestive reflexes triggered by pharyngeal stimulation can protect the airways by clearing fluid from the pharynx. The objective of this study was to determine the relationship between the maximum capacity of fluid that can safely dwell in the hypopharynx [hypopharyngeal safe volume (HPSV)] before spilling into the larynx and the threshold volumes required to trigger pharyngoglottal closure reflex (PGCR), pharyngo-upper esophageal sphincter contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS). Twenty-five healthy volunteers (mean age 24 yr, 8 males) were studied in the semi-inclined supine position. PGCR, PUCR, and RPS were elicited using techniques of concurrent upper esophageal sphincter manometry and pharyngo-laryngoscopy. The hypopharynx was then anesthetized to abolish RPS. HPSV was determined by infusing water in the pharynx, and perfusion was stopped when the infusate reached the superior margin of the interarytenoid fold. The threshold volumes for triggering PGCR, PUCR, and RPS by slow and rapid injections before pharyngeal anesthesia were 0.18 ± 0.02 and 0.09 ± 0.02 ml; 0.20 ± 0.020 and 0.13 ± 0.04 ml; and 0.61 ± 0.04 and 0.4 ± 0.06 ml, respectively. All of the above volumes were significantly smaller than the HPSV (0.70 ± 0.06 ml, P < 0.01) except for the threshold volume to elicit RPS during slow perfusion, which was not significantly different (P = 0.23). We conclude that pharyngeal aerodigestive reflexes are triggered by both slow and rapid pharyngeal perfusion of water at significantly smaller volumes than the maximum capacity of the hypopharynx to safely hold contents without spilling into the airway. These reflexes thereby aid in prevention of aspiration.

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

BACKGROUND & AIMS

Direct evidence to support the airway protective function of aerodigestive reflexes triggered by pharyngeal stimulation was previously demonstrated by abolishing these reflexes by topical pharyngeal anesthesia in normal subjects. Studies have also shown that these reflexes deteriorate in cigarette smokers. Aim of this study was to determine the influence of defective pharyngeal aerodigestive reflexes on airway protection in cigarette smokers.

METHODS

Pharyngoglottal Closure reflex; PGCR, Pharyngo-UES Contractile reflex; PUCR, and Reflexive Pharyngeal Swallow; RPS were studied in 15 healthy non-smokers (24.2±3.3 SD y, 7 males) and 15 healthy chronic smokers (27.3±8.1, 7 males). To elicit these reflexes and to evaluate aspiration, colored water was perfused into the hypopharynx at the rate of 1 mL/min. Maximum volume of water that can safely dwell in the hypopharynx before spilling into the larynx (Hypopharyngeal Safe Volume; HPSV) and the threshold volume to elicit PGCR, PUCR, and RPS were determined in smokers and results compared with non-smokers.

RESULTS

At baseline, RPS was elicited in all non-smokers (100%) and in only 3 of 15 smokers (20%; P<.001). None of the non-smokers showed evidence of laryngeal spillage of water, whereas 12 of 15 smokers with absent RPS had laryngeal spillage. Pharyngeal anesthesia abolished RPS reflex in all non-smokers resulting in laryngeal spillage. The HPSV was 0.61±0.06 mL and 0.76±0.06 mL in non-smokers and smokers respectively (P=.1).

CONCLUSIONS

Deteriorated reflexive pharyngeal swallow in chronic cigarette smokers predispose them to risks of aspiration and similarly, abolishing this reflex in non-smokers also results in laryngeal spillage. These observations directly demonstrate the airway protective function of RPS.

Physiology and pathophysiology of glottic reflexes and pulmonary aspiration: from neonates to adults

Pulmonary aspiration is the consequence of abnormal entry of fluid, particulate material, or endogenous secretions into the airway. The two main types of aspiration scenarios include anterograde aspiration, which occurs during swallowing, and retrograde aspiration, which can occur during gastroesophageal reflux (GER) events. The important structures that protect against aspiration include the aerodigestive apparatus: pharynx, upper esophageal sphincter, esophageal body, glottis and vocal cords, and airway. In this article we review the neuroanatomy, physiology, and pathophysiology pertinent to glottic reflexes and airway aspiration across the age spectrum from neonates to adults. We also discuss recent advances in our understanding of glottal reflexes and the relationship of these reflexes to developmental anatomy and physiology, the pathophysiology of aspiration, and aerodigestive interactions.

Effects of postnatal smoke exposure on laryngeal chemoreflexes in newborn lambs

Laryngeal chemoreflexes (LCR), which are elicited by the contact of liquids such as gastric refluxate with laryngeal mucosa, may trigger some cases of sudden infant death syndrome. Indeed, while LCR in mature mammals consist of protective responses, previous animal data have shown that LCR in immature newborns can include laryngospasm, apnea, bradycardia, and desaturation. The present study was aimed at testing the hypothesis that postnatal exposure to cigarette smoke is responsible for enhancing cardiorespiratory inhibition observed with LCR. Eight lambs were exposed to cigarette smoke (20 cigarettes/day) over 16 days and compared with seven control lambs. Urinary cotinine/creatinine ratio was measured at a level relevant to previously published levels in infants. On days 15 and 16, 0.5 ml of HCl (pH 2), milk, distilled water, or saline was injected onto the larynx via a chronic supraglottal catheter during sleep. Results showed that exposure to cigarette smoke enhanced respiratory inhibition (P < 0.05) and tended to enhance cardiac inhibition and decrease swallowing and arousal during LCR (P < 0.1). Overall, these results were observed independently of the state of alertness and the experimental solution tested. In conclusion, 16-day postnatal exposure to cigarette smoke increases cardiorespiratory inhibition and decreases protective mechanisms during LCR in nonsedated full-term lambs.

Sensory input pathways and mechanisms in swallowing: a review

Over the past 20 years, research on the physiology of swallowing has confirmed that the oropharyngeal swallowing process can be modulated, both volitionally and in response to different sensory stimuli. In this review we identify what is known regarding the sensory pathways and mechanisms that are now thought to influence swallowing motor control and evoke its response. By synthesizing the current state of research evidence and knowledge, we identify continuing gaps in our knowledge of these mechanisms and pose questions for future research.

Effect of systemic alcohol and nicotine on airway protective reflexes

OBJECTIVES

Injection of water into the pharynx induces contraction of the upper esophageal sphincter (UES), triggers the pharyngo-UES contractile reflex (PUCR), and at a higher volume, triggers an irrepressible swallow, the reflexive pharyngeal swallow (RPS). These aerodigestive reflexes have been proposed to reduce the risks of aspiration. Alcohol ingestion can predispose to aspiration and previous studies have shown that cigarette smoking can adversely affect these reflexes. It is not known whether this is a local effect of smoking on the pharynx or a systemic effect of nicotine. The aim of this study was to elucidate the effect of systemic alcohol and nicotine on PUCR and RPS.

METHODS

Ten healthy non-smoking subjects (8 men, 2 women; mean age: 32+/-3 s.d. years) and 10 healthy chronic smokers (7 men, 3 women; 34+/-8 years) with no history of alcohol abuse were studied. Using previously described techniques, the above reflexes were elicited by rapid and slow water injections into the pharynx, before and after an intravenous injection of 5% alcohol (breath alcohol level of 0.1%), before and after smoking, and before and after a nicotine patch was applied. Blood nicotine levels were measured.

RESULTS

During rapid and slow water injections, alcohol significantly increased the threshold volume (ml) to trigger PUCR and RPS (rapid: PUCR: baseline 0.2+/-0.05, alcohol 0.4+/-0.09; P=0.022; RPS: baseline 0.5+/-0.17, alcohol 0.8+/-0.19; P=0.01, slow: PUCR: baseline 0.2+/-0.03, alcohol 0.4+/-0.08; P=0.012; RPS: baseline 3.0+/-0.3, alcohol 4.6+/-0.5; P=0.028). During rapid water injections, acute smoking increased the threshold volume to trigger PUCR and RPS (PUCR: baseline 0.4+/-0.06, smoking 0.67+/-0.09; P=0.03; RPS: baseline 0.7+/-0.03, smoking 1.1+/-0.1; P=0.001). No similar increases were noted after a nicotine patch was applied.

CONCLUSIONS

Acute systemic alcohol exposure inhibits the elicitation PUCR and RPS. Unlike cigarette smoking, systemic nicotine does not alter the elicitation of these reflexes.

Definition and implications of novel pharyngo-glottal reflex in human infants using concurrent manometry ultrasonography

OBJECTIVES

Glottal relationships during swallowing dominate the etiology of dysphagia. We investigated the pharyngo-glottal relationships during basal and adaptive swallowing.

METHODS

Temporal changes in glottal closure kinetics (frequency, response latency, and duration) with spontaneous and adaptive pharyngeal swallows were defined in 12 infants using concurrent pharyngoesophageal manometry and ultrasonography of the glottis.

RESULTS

Frequency, response latency, and duration of glottal closure with spontaneous swallows (n=53) were 100%, 0.27+/-0.1 s, and 1+/-0.22 s, respectively. The glottis adducted earlier (P<0.0001 vs. upper esophageal sphincter relaxation) within the same respiratory phase as swallow (P=0.03). With pharyngeal provocations (n=41), glottal adduction (pharyngo-glottal closure reflex (PGCR)) was noted first and then again with pharyngeal reflexive swallow (PRS). The frequency, response latency, and duration of glottal closure with PGCR were 100%, 0.56+/-0.13 s, and 0.52+/-0.1 s, respectively. Response latency to PRS was 3.24+/-0.33 s; the glottis adducted 97% within 0.36+/-0.08 s in the same respiratory phase (P=0.03), and remained adducted for 3.08+/-0.71 s. Glottal adduction was the quickest with spontaneous swallow (P=0.04 vs. PGCR), and the duration was the longest during PRS (P<0.005 vs. PGCR or spontaneous swallow).

CONCLUSIONS

Glottal adduction during basal or adaptive swallowing reflexes occurs in either respiratory phase, thus ensuring airway protection against pre-deglutitive or deglutitive aspiration. The independent existence and magnitude (duration of adduction) of PGCR suggests a hypervigilant state of the glottis in preventing aspiration during swallowing or during high gastroesophageal reflux events. Investigation of pharyngeal-glottal relationships with the use of noninvasive methods may be more acceptable across the age spectrum.

Manometric evidence for a phonation-induced UES contractile reflex

The mechanism against entry of gastric content into the pharynx during high-intensity vocalization such as seen among professional singers is not known. We hypothesized that phonation-induced upper esophageal sphincter (UES) contraction enhances the pressure barrier against entry of gastroesophageal contents into pharynx. To determine and compare the effect of phonation on luminal pressures of the esophagus and its sphincters, we studied 17 healthy volunteers (7 male, 10 female) by concurrent high-resolution manometry and voice analysis. We tested high- and low-pitch vowel sounds. Findings were verified in six subjects by UES manometry using a water-perfused sleeve device. Eight of the volunteers (2 male, 6 female) had concurrent video fluoroscopy with high-resolution manometry and voice recording. Fluoroscopic images were analyzed for laryngeal movement. To define the sex-based effect, subgroup analysis was performed. All tested phonation frequencies and intensities induced a significant increase in UES pressure (UESP) compared with prephonation pressure. The magnitude of the UESP increase was significantly higher than that of the distal esophagus, the lower esophageal sphincter (LES), and the stomach. Concurrent videofluoroscopy did not show posterior laryngeal movement during phonation, eliminating a purely mechanical cause for phonation-induced UESP increase. Subgroup analysis demonstrated phonation-induced UESP increases in males that were significantly greater than those of females. Phonation induces a significant increase in UESP, suggesting the existence of a phonation-induced UES contractile reflex. UESP increase due to this reflex is significantly higher than that of the distal esophagus, LES, and stomach. The phonation-induced UESP increase is influenced by sex.

Pharyngeal swallowing: defining pharyngeal and upper esophageal sphincter relationships in human neonates

OBJECTIVE

To test the hypothesis that the sensorimotor characteristics of the reflexes evoked on stimulation with air and water infusions differ by studying the effect of pharyngeal stimulation on pharyngeal-upper esophageal sphincter (UES) interactions in healthy neonates.

STUDY DESIGN

Pharyngo-UES-esophageal manometry was recorded in 10 neonates at 39 +/- 4 weeks postmenstrual age. Pharyngeal infusions (n = 155) of air (0.1 to 2.0 mL) and sterile water (0.1 to 0.5 mL) were given. Two types of reflexes were recognized: pharyngeal reflexive swallowing (PRS) and pharyngo-UES-contractile reflex (PUCR). Frequency occurrence, distribution of reflexes, threshold volume, response time, and stimulus-response relationship were evaluated.

RESULTS

The reflex response rates were 30% for air and 76% for water (P < .001). PRS was more frequent than PUCR with air and water (P < .05), even though the stimulation thresholds and response latencies were similar. Graded volumes of water but not air resulted in an increased frequency of PRS (P < .01).

CONCLUSIONS

PRS is more frequent than PUCR, and the 2 reflexes have distinctive characteristics in air and water stimuli. Both PRS and PUCR have implications for the evaluation of swallowing in infants.

Safety and feasibility of evaluating airway-protective reflexes during sleep: new technique and preliminary results

BACKGROUND

The airway is vulnerable to aspiration during sleep. The integrity of aerodigestive-protective reflexes during sleep has not been studied previously because of a lack of adequate techniques.

OBJECTIVE

To determine the safety and the feasibility of a new technique to elicit pharyngoglottal closure reflex (PGCR), pharyngo-upper-esophageal sphincter (UES) pressure contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS) during sleep.

SETTING

Outpatient sleep laboratory.

DESIGN AND INTERVENTION

PGCR, PUCR, and RPS were elicited in 3 subjects by injecting colored water into the pharynx through a specially designed UES manometry catheter to which a thin videoendoscope was taped. This assembly was passed transnasally and positioned to obtain UES-pressure recordings and adequate endoscopic glottic views. Sleep was monitored by polysomnography, and all modalities were synchronized by using a timer. Subjects were evaluated while awake and during stage I sleep.

RESULTS

All subjects were monitored for 3 hours of natural sleep, during which several periods of stage I sleep were observed. While awake, PGCR, PUCR, and RPS were elicited in all subjects. During sleep, PGCR was present in all, PUCR in 2, and RPS in 2 (1 after arousal) subjects. Threshold volumes for reflex elicitation were not significantly different between the awake state and stage I sleep. None of the subjects exhibited laryngeal penetration or aspiration.

LIMITATIONS

Small numbers of subjects were studied only in stage I sleep.

CONCLUSIONS

When using the above technique, it is safe and feasible to study aerodigestive reflexes during sleep. Preliminary data suggest that PGCR, PUCR, and RPS can be elicited during sleep.

Risk factors for sporadic community-acquired Legionnaires' disease. A 3-year national case–control study

OBJECTIVE

Risk factors for sporadic community-acquired Legionnaires' disease (LD) have been studied in the past, well before the widespread introduction of the urinary antigen test. Our objective was to evaluate the impact of the concomitant decrease in underdiagnosis on established and unknown risk factors for LD.

STUDY DESIGN

Prospective case-control study.

METHODS

From 1 July 1998 to 30 June 2001, 228 LD cases and 293 controls were included for a national case-control study. Patients were included upon notification provided that they fulfilled international criteria for confirmed LD.

RESULTS

A history of diabetes mellitus, current tobacco smoking, travelling abroad, spending one or more nights away from home not leaving the country and being a driver by profession were independent risk factors. LD patients who had travelled abroad during their incubation period differed from LD patients who had not. They appeared healthier than non- or domestic travellers with respect to a history of coronary disease, pulmonary disease, current use of corticosteroids or immunosuppressives and any medication. Also the environmental risk factors differed significantly for the two groups.

CONCLUSIONS

The finding of two distinct populations of LD patients calls for a differentiated preventive strategy.

Etiologic clues from the similarity of histology-specific trends in esophageal and lung cancers

OBJECTIVE

We tested whether descriptive evidence exists for differing roles of specific tobacco constituents on different histologic subtypes of esophageal cancer. Esophageal adenocarcinoma incidence rates are increasing while squamous cell esophageal cancer rates are declining in Westernized countries as are the histology-specific lung counterparts. Squamous cell lung cancers, while caused by smoking, are believed to be caused by different constituents of tobacco smoke than lung adenocarcinomas. Smoking is also a risk factor for esophageal cancers.

METHODS

We compared patterns of incidence of squamous cell cancers of the lung with those of squamous cell esophageal cancers, and incidence trends in lung adenocarcinomas with those of esophageal adenocarcinomas during the time period from 1976 to 2000 using data from the population-based Los Angeles Cancer Surveillance Program.

RESULTS

Rates of squamous cell esophageal cancer declined in a similar fashion to those of squamous cell lung cancer, while esophageal adenocarcinoma incidence increased at a rate similar to that of lung adenocarcinoma, in both men and women, and blacks and whites. Histology-specific socio-economic gradients in lung and esophageal cancers were also strikingly similar. Increases in esophageal adenocarcinoma were confined to the lower third of the esophagus.

CONCLUSIONS

While increases in obesity over time might explain these trends, they are also consistent with a specific effect of some constituent of tobacco smoke working through reflux disease to cause esophageal adenocarcinoma.

Meta-analysis of upper probe measurements in normal subjects and patients with laryngopharyngeal reflux

We report a meta-analysis of a series of studies in which 24-hour ambulatory pH monitoring was performed in 1) normal subjects, 2) the normal control subjects in studies of laryngopharyngeal reflux (LPR), and 3) the patients with LPR in these controlled studies. The statistical analysis utilized the fixed-effects model by Mantel-Haenszel and the random-effects mixed model. There were 16 studies from the past 12 years that fulfilled the inclusion criteria. They involved 793 subjects (264 normal and 529 with LPR). The numbers of positive pharyngeal reflux events for normal subjects and for patients with LPR differed with a p value of <.0001. There was also a significant difference in the mean percentage of acid exposure times between normal subjects and patients with LPR (p = .003). We conclude that the upper probe gives accurate and consistent information in normal subjects and patients with LPR. The numbers of reflux events and acid exposure times are most important in distinguishing normal subjects from patients with LPR. The technology and methodology of probe testing is quite reliable and is consistent on a worldwide basis.