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sTu1997

Proximal Aero-Digestive and Respiratory Interactions in Infants With HypoxicIschemic Encephalopathy (HIE)Ish K. Gulati, Theresa Shubert, Xiaoyu Gao, Sudarshan Jadcherla

BACKGROUND: Management of oral secretions and aerodigestive symptoms is a challengingproblem in infants with HIE. Timeliness and coordination of neuromotor activation inresponse to pharyngeal stimulation are crucial for swallowing and airway protection. Wehave demonstrated that neonates with HIE have altered esophageal body response kineticswhen compared with healthy controls, but mechanisms regarding the pharyngeal phase ofdysphagia remain unclear. AIMS: To test the hypothesis that in infants with HIE, pharyngealprovocation alters swallowing and upper esophageal sphincter (UES) coordination. METH-ODS: Provocative pharyngo-esophageal motility studies were performed using a water per-fused pneumohydraulic micromanometric system with a catheter assembly comprising of apharyngeal infusion port, UES and lower esophageal sphincter sleeves, and channels for thepharynx, esophageal body, and stomach. Control data from 10 orally feeding infants studiedat 39.7 ± 2.8 wks postmenstrual age (PMA) were compared with data from 25 infants withHIE studied at 41.9 ± 2.9 wks PMA. Median APGAR scores for the Control vs. HIE groupsrespectively were 6 vs. 1 at 1 minute (P<0.01), and 8 vs. 3 at 5 minutes (P<0.01). A totalof 240 (69 from controls and 171 from HIE) graded volumetric pharyngeal infusions ofsterile water (0.1ml, 0.3mL, 0.5mL, all in triplicate) were analyzed for pharyngeal, UES,and respiratory interactions. RESULTS: Although the timing and duration of the infusedstimuli were similar in both groups, the responses were distinct (Table 1). The responselatency to the onset of terminal swallow correlated highly with the duration of the respiratorychange to restoration (r=0.93, P<0.05). Relationship between infusion volume and thecontraction magnitude of pharyngo-UES contractile reflex (PUCR) was similar. However,pharyngeal swallow frequency increased with increment of infusion (P<0.01) in controlsonly, but not so in infants with HIE (P=0.6). CONCLUSIONS: Contrasting with controls,infants with Hypoxic Ischemic Encephalopathy exhibit following malfunctions: 1) Dysfunc-tional central swallowing generation, both in terms of frequency and characteristics, contribut-ing to the mechanisms of dysphagia. 2) Heightened UES resting pressures and increasedoccurrence of PUCR in response to the infusion. This increased tonicity and reactivity ofthe UES leads pooling of secretions at the pharyngeal level, as well as delayed esophagealclearance. 3) Significant prolonged disturbances in respiratory rhythm in response to pharyn-geal provocation are suggestive of aerodigestive maladaptation. Finally these findings impli-cate supranuclear or nuclear level lesions in HIE infants, that may modify the functions ofVagal and respiratory neural pathways involved with swallowing, respiration and aerodiges-tive protection. *Supported in part by 2RO1DK 068158 (Jadcherla)Table 1. Effect Of Pharyngeal Provocation On Proximal Aero-Digestive Interaction Kinetics

Data are stated as % or mean ± SEM. PRS- Pharyngeal reflexive swallow, PUCR- pharyngo-UES contractile reflex, #- Number of responses per stimulus

Tu1998

Inter-Swallow Variability Assessed by Means of Automated ImpedanceManometry Is Different in Patients With Oropharyngeal Dysphagia Comparedto Healthy VolunteersClaudia Liesenborghs, Charlotte Scheerens, Margot Selleslagh, Eddy W. Dejaeger, TaherOmari, Jan F. Tack, Nathalie Rommel

Background An important factor in the assessment of oropharyngeal dysphagia (OD) is thechallenge of inter-swallow variability. This concerns the variation between swallows withinone investigation (e.g. the influence of fatigue after multiple swallows) as well as the variationbetween investigations at different moments in time (e.g. fluctuating alertness in dementiapatients). Automated Impedance Manometry (AIM) is an objective, non-radiological tech-nique to assess pharyngeal and upper esophageal sphincter (UES) (dys)function duringdeglutition. In this study we aimed to compare the inter-swallow variability during a singleinvestigation in OD patients versus healthy controls by means of the AIM resulting pressure-flow parameters. Methods We studied 43 patients (21 males, mean 62y, range 16-90y)referred for videomanometric assessment with OD complaints and 12 healthy volunteers (6males, mean 28y, range 22-50y). All subjects underwent impedance manometry assessmentusing a high resolution solid-state catheter with 36 pressure sensors spaced at 1cm and 12or 16 impedance channels spaced at 2cm. Each subject performed 3 or 4 liquid swallowsof 5 or 10ml (bolus volume controlled within subject). Impedance manometry data wereanalyzed using AIM analysis resulting in numerical pressure-flow parameters. Bolus swallowsinterquartile ranges for each parameter were calculated per subject as a measure of individualinter-swallow variability. The interquartile ranges of the patients with OD were evaluatedagainst those of healthy volunteers by comparing median interquartile ranges per groupusing the Mann-Whitney U test (Table 1). Results For 5 out of the 12 swallow parametersassessed, median interquartile ranges significantly differed between patients and healthy

S-894AGA Abstracts

volunteers. Notably, 4/5 of these parameters were pressure-flow metrics combining informa-tion of both impedance and manometry measurements. Two global parameters, indicativeof prediction of aspiration risk (Swallow Risk Index) and post swallow bolus residue (Inte-grated nadir impedance to impedance ratio) respectively, demonstrated greater variation inpatients compared to healthy volunteers. Our data also show that with repeated swallows,pharyngeal and UES compliance is more variable in OD patients compared to controls(Pharyngeal and UES pressure at Nadir Impedance and UES Nadir Pressure). ConclusionIn this study we used pressure-flow analysis to demonstrate that inter-swallow variabilityis larger in oropharyngeal dysphagia patients compared to healthy volunteers. Consequently,deglutition of multiple boluses during a swallow examination is necessary to obtain reliableinformation on swallow function by means of impedance manometry assessment. As thismethodology is non-radiological, repeated measurements can be easily implemented.Table 1. Interquartile ranges calculated for 3 or 4 swallows per subject presented as Medians[Quartile 1 - Quartile 3]. P-values for the Mann-Whitney U Test are listed with significantp-values that survived Bonferroni correction marked with *.

Tu1999

Feasibility Model of Concurrent Pharyngeal Provocation and High ResolutionManometry (HRM) in Human NeonatesPreceousa S. Jensen, Xiaoyu Gao, Sudarshan Jadcherla

BACKGROUND: The pharynx is a site of constant stimulation throughout the suck-swallowprocess necessary for successful oral feeding. With the advent of HRM, multi-dimensionanalysis of basal swallow characteristics has been possible. Although the pharyngo-esophagealadaptive responses to pharyngeal stimulus has been shown by us using conventional waterperfusion manometry in neonates, feasibility and characterization of such responses usingconcurrent pharyngeal provocation with HRM have not been performed in human neonates.AIMS: To determine the feasibility, safety, and characteristics of concurrent pharyngealprovocation induced motility changes with HRM in human neonates METHODS: 10 neuro-logically normal infants (4 males, born at 34.0 (31.3 - 36.3) wks) were evaluated at 44.5(41.5 - 46.8) wks post-menstrual age using HRM, respiratory inductance plethysmographyand nasal airflow thermister to demonstrate a feasibility model of concurrent pharyngealprovocation and HRM. The pharyngeal infusion catheter was juxtaposed with HRM catheter.Pharyngeal and respiratory responses to graded volumes (0.1 mL, 0.3 mL, and 0.5 mL)of pharyngeal infusions are reported. Pharyngeal characteristics analyzed were pharyngealreflexive swallowing (PRS) vs. pharyngo-upper esophageal sphincter contractile reflex (PUCR)and number, duration and frequency of pharyngeal peaks in response to the incrementalvolume provocations. Distal contractile integrity (DCI), distal latency (DL), and contractilefront velocity (CFV) were used to analyze esophageal body propagation. Upper esophagealsphincter (UES) and lower esophageal sphincter (LES) were evaluated using the IntegratedRelaxation Pressure (IRP), in addition to characterization of deglutition apnea and respiratoryrate changes. Statistical analysis was performed using linear mixed models, GEE models andANOVA. Data are presented as median (IQR) or mean ± SE. RESULTS: Overall, there were72 analyzable pharyngeal water infusions. PRS is the most common response (See Table 1).The rate of LES relaxation increases with incremental volume infusions (IRP 1s, 2s, 3s, 4s,5s p<0.05). However, UES relaxation in relation to increasing volumes were similar (IRP0.2s, 0.4s, 0.6s, 0.8s, 1s p-value >0.05). Volume of infusions had no effect on the occurrenceof deglutition apnea or respiratory rate changes (p-value > 0.3) but increased volumeinfusions resulted in increased duration of both deglutition apnea and respiratory rate. Nocardiorespiratory adverse events occurred during the study. CONCLUSIONS: Concurrentpharyngeal provocation and HRM are feasible and safe in human infants. Analyses of UES,esophageal body, and LES characterization can therefore be used to distinguish adaptivepharyngo-esophagea l ref lexes in hea lth and disease. *Supported in part by2RO1DK068158 (Jadcherla)Table 1. Pharyngo-esophageal and Respiratory Responses to Pharyngeal Provocation