Roxann Diez Gross

The coordination of breathing and swallowing in chronic obstructive pulmonary disease.

RATIONALE During deglutition, a strongly preferred exhale-swallow-exhale pattern has been shown in healthy adults. Disruption of this pattern can provoke prandial aspiration. Impaired coordination of breathing and swallowing has been measured in patients with chronic obstructive pulmonary disease (COPD) during the exacerbated state, but no reports describe the coordination of breathing and swallowing in stable patients with COPD during oral intake. OBJECTIVES To test the hypothesis that persons with moderate to severe COPD would show disordered coordination of breathing and swallowing during oral intake when compared with a matched, healthy control group. METHODS This study used a prospective, repeated measures design using 25 subjects with COPD and 25 control subjects. Respiratory inductance plethysmography and nasal thermistry were used simultaneously to track respiratory signals. Submental surface EMG was used to mark the presence of each swallow within the respiratory cycle. Data were recorded while participants randomly and spontaneously swallowed solids and semi-solids. MEASUREMENTS AND MAIN RESULTS Logistic regression showed that participants with COPD swallowed solid food during inhalation more frequently than normal subjects (P = 0.002) and had a significantly higher rate of inhaling after swallowing semi-solid material (P < 0.001). Subjects with COPD also swallowed pudding at low Vt significantly more often than they did the cookie (P = 0.006). Conversely, the control subjects swallowed cookie at low Vt significantly more often than pudding (P = 0.034). Significant differences in deglutitive apnea durations were also found. CONCLUSIONS Patients with COPD exhibit disrupted coordination of the respiratory cycle with deglutition. Disrupted breathing-swallowing coordination could increase the risk of aspiration in patients with advanced COPD and may contribute to exacerbations.

Subglottic Air Pressure: A Key Component of Swallowing Efficiency

The relationship between tracheostomy and swallowing dysfunction has been long recognized. Often this dysfunction is manifested by aspiration, for which a number of etiologic factors may be responsible. Disruption of glottic closure has been previously demonstrated in association with the presence of an indwelling tracheostomy tube. The plugging or removal of the tracheostomy tube, or the use of an expiratory air valve, has been demonstrated to decrease aspiration and improve swallowing function. Measurement of subglottic pressure through an indwelling tracheostomy tube during swallowing demonstrated pressure peaks occurring concomitant with swallowing and laryngeal elevation. This presentation will review the evidence supporting the role of subglottic pressure rise in swallowing efficiency. Current investigational activity will be reviewed, and new areas for study will be suggested.

The Coordination of Breathing and Swallowing in Parkinson’s Disease

Multiple investigations have determined that healthy adults swallow most often during exhalation and that exhalation regularly follows the swallow, even when a swallow occurs during inhalation. We hypothesized that persons with idiopathic Parkinson’s disease would demonstrate impaired breathing and swallowing coordination during spontaneous eating. Twenty-five healthy volunteers and 25 Parkinson’s disease patients spontaneously swallowed calibrated pudding and cookie portions while simultaneous nasal airflow and respiratory inductance plethysmography were used to track spontaneous breathing. Surface EMG was used to record the timing of each swallow within the respiratory cycle. When compared to the healthy control group, those with Parkinson’s disease swallowed significantly more often during inhalation and at low tidal volumes. The Parkinson’s participants also exhibited significantly more postswallow inhalation for both consistencies. Only the healthy subjects exhibited significantly longer deglutitive apnea when swallows that occurred during inhalation were compared with those that occurred during exhalation. The high incidence of oropharyngeal dysphagia and risk of aspiration pneumonia found in Parkinson’s disease patients may be partially attributable to impaired coordination of breathing and swallowing.

Physiologic Effects of Open and Closed Tracheostomy Tubes on the Pharyngeal Swallow

Studies linking aspiration and dysphagia to an open tracheostomy tube exemplify the possibility that the larynx may have an influence on oropharyngeal swallow function. Experiments addressing the effects of tracheostomy tube occlusion during the swallow have looked at the presence and severity of aspiration, but few have included measurements that capture the changes in swallowing physiology. Also, hypotheses for the importance of near-normal subglottic air pressure during the swallow have not been offered to date. As such, the aim of this study was to compare the depth of laryngeal penetration, bolus speed, and duration of pharyngeal muscle contraction during the swallow in individuals with tracheostomy tubes while their tubes were open and closed. The results of this series of experiments indicate that within the same tracheostomized patient, pharyngeal swallowing physiology is measurably different in the absence of subglottic air pressure (open tube) as compared to the closed tube condition.

Direct Measurement of Subglottic Air Pressure While Swallowing

Objective: The subglottic pressure theory for swallowing asserts that laryngeal mechanoreceptors have a role in the regulation of swallowing function. The primary purpose of this study was to determine if subglottic air pressure is generated during swallowing in a healthy, nontracheostomized person.

Subclinical dysphagia in persons with Prader–Willi syndrome

Prader–Willi Syndrome (PWS) is caused by a genetic imprinting abnormality resulting from the lack of expression of the paternal genes at 15q11–q13. Intellectual disability, low muscle tone, and life‐threatening hyperphagia are hallmarks of the phenotype. The need for the Heimlich maneuver, death from choking, and pulmonary infection occur in a disproportionally high number of persons with PWS. The widely held belief is that eating behaviors are responsible for choking and aspiration; yet, no investigation had sought to determine if swallowing impairments were present in persons with PWS. To address this research and clinical gap, simultaneous videofluoroscopy and nasal respiratory signals were used to record swallowing function and breathing/swallowing coordination in 30 participants with PWS. Subjects consumed thin liquid and barium cookies under two randomized conditions as follows: (i) controlled (cues to swallow and standardized bolus sizes); (ii) spontaneous (no cues or bolus size control). Under videofluoroscopy, the cohort showed disordered pharyngeal and esophageal swallowing in both conditions with disturbances in timing, clearance, and coordination of swallowing with the respiratory cycle. No participant showed a sensory response such as attempting to clear residue or coughing; thereby supporting the lack of overt symptoms. We conclude that the high death rate from choking and pulmonary infection in children and adults with PWS may be related, in part, to underlying, asymptomatic dysphagia. The combination of rapid eating and dysphagia would increase the risk of aspiration‐related morbidity and mortality.

R168: Safety of Tracheostomy Speaking Valve Use during Sleep

tongue volume, small PAS diameter at the nasal and mandibular planes, a smaller PAS area, and a long MP-H distance hold relevance in patients with OSA. SIGNIFICANCE: Anatomic parameters can predict airway obstruction in patients with OSA. Outome measures can complement available tomographic MRI and cephalometry in evaluating patients with OSA and possibly guide surgical planning. SUPPORT: None

R060: Breathing-Swallowing Pattern in Tracheostomy vs. Controls

Healthy adults almost exclusively exhibit an exhale-swallow-exhale pattern while eating. Deviation from the normal pattern could place individuals at risk for aspiration. Should inhalation take place after the swallow, aspiration of any residue remaining is more likely to occur. The importance of timing swallows with exhalation is apparent in non-neurologically impaired tracheostomy patients in whom it has been shown that aspiration and dysphagia can occur. We hypothesized that persons with open, indwelling tracheostomy tubes would show a disorganization of the normal coordination of breathing and swallowing while eating. The investigation was a prospective, repeated measures design. Two groups were studied: one with an indwelling tracheostomy tube and a healthy, control group. Respiratory inductance plethysmography and thermistry distinguished exhalation from inhalation. Swallows were detected with submental surface EMG electrodes. Participants sat at a table and ate ten, 5ml, semi-solid boluses (pudding) and nine, 25g cookie portions. Data were analyzed using the test for binomial proportions with alpha set at p less than 0.05. The proportion of swallows that were followed by inhalation was significantly greater in the tracheostomy group (p=0.009). Within the healthy group, the proportion of cookie swallows that occurred during inhalation was significantly smaller than pudding swallows (p=0.0004). The proportion of swallows that occurred during inhalation (cookie vs. pudding) did not differ in the tracheostomy group (p=0.06). Unlike those with an indwelling tracheostomy, healthy persons were less likely to swallow during inhalation if the bolus required mastication. Tracheostomy subjects had a significantly higher proportion of swallows that were followed by inhalation which may place them at increased risk for prandial aspiration. The omission of respiratory information in today’s clinical practice may result in reduced diagnostic accuracy and treatment effectiveness if normal respiratory patterning during deglutition is shown to be critical to safe swallowing. Funded by VA RR&D Merit Review. Work completed at the Pittsburgh VA. Swallows during inhalation Tracheostomy vs. Control p value Pudding 12/99 (12%) 22/230 (10%) 0.6 Cookie 3/76 (4%) 4/214 (2%) 0.1 Total 15/175 (9%) 26/444 (6%) 0.2 Post swallow inhalation Tracheostomy vs. Control p value Pudding 19/99 (19%) 17/230 (7%) *0.001 Cookie 8/76 (11%) 20/214 (9%) 0.6 Total 27/175 (15%) 37/444 (8%) *0.009 Swallows during inhalation p value Trach Pudding 12/99 (12%) vs. Cookie 3/76 (4%) 0.06 Controls Pudding 22/230 (10%) vs. Cookie 4/214 (2%) *0 .0004 Post swallow inhalation Trach Pudding 19/99 (19%) Cookie 8/76 (11%) 0.14 Controls Pudding 17/230 (7%) Cookie 20/214 (9%) 0.4 * significance Results Participants: The reason for the tracheostomy was not restricted, nor was the duration or size of the cuffed tracheostomy tube. •Current diet included purees and soft solids. •Those with COPD, neurologic disease or current use of psychotropic drugs and barbiturates were not included. •Mean age was 58 years for trach group and 64 years for controls. •Methods: •Respiratory inductance plethysmography was used to detect breathing motion of the chest and abdomen. • A Thermistor detected the direction of airflow at the hub of the tracheostomy tube with the cuff inflated. • Swallows were detected with submental surface EMG electrodes and a tag was also placed after the subject confirmed that they had swallowed. •Participants sat at a table and ate ten, 5ml semi-solid boluses (pudding) and nine, 25g cookie portions with the cuff fully inflated. •Data were analyzed using the test for binomial proportions with alpha set at p less than 0.05. Methods and Materials •These pilot data suggest that disordered breathing and swallowing interactions may result when the upper airway and alimentary tracts are functionally separated by an indwelling tracheostomy tube with inflated cuff. •Inhalation after the swallow may increase the risk or frequency of aspiration when prandial residue is present. •Small number of subjects in tracheostomy group may have reduced statistical power. Conclusions and limitations Introduction •A multitude of investigations have determined that humans without neurologic, respiratory or other diseases (i.e. normal subjects) swallow almost exclusively during exhalation. • Persistent coordination of swallowing with the exhalation phase may be a method of assuring the highest degree of positive subglottic air pressure during the swallow. •Exhalation nearly unequivocally follows the swallow, even if a swallow should occur during inhalation. •Exhalatory airflow after the swallow may serve as an airway clearing mechanism if any material entered the airway while swallowing. •Should inhalation take place after the swallow, aspiration of any residue remaining in the upper airway is much more likely to occur. CHART or PICTURE CHART or PICTURE Raw data of a control subject Raw data of a tracheostomy subject

Breathing and Swallowing: The Next Frontier

Abstract The anatomical overlap of the pathways for air passage and nutrition necessitate precise coordination between the two vital functions. Neuroanatomic structures in the brainstem for sucking, breathing, and swallowing are also in close proximity and must swiftly coordinate the processes. In a healthy neonate, the oropharyngeal experience and stimulation of early feeding enables respiratory control during suckling to develop. Despite wide variability among the methods used to investigate breathing and swallowing coordination in infancy, a consistent finding of postswallow exhalation has been reported. Postswallow exhalation is significant because the positive airflow of exhalation is believed to provide airway clearance. Preterm neonates and infants swallow during all phases of the respiratory cycle, but ultimately progress to the most commonly reported pattern, which is inhale‐swallow‐exhale. This pattern is similar to the adult pattern of exhale‐swallow‐exhale. Monitoring respiratory signals during nonnutritive sucking and early feeding may help to identify newborns with increased risk of aspiration and assist with clinical decision making.