Single Swallows Research Articles

Mechanisms of gastroesophageal reflux in healthy premature infants.

The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of healthy preterm infants. Esophageal motility was recorded for 2 to 3 hours after a feeding in 24 preterm infants, 31 to 38 weeks' postmenstrual age, by using a sleeveside hole micromanometric assembly incorporating a pH probe. Sixty acid GER episodes were recorded by pH probe, and 133 non-acid GER episodes were recorded manometrically by the presence of esophageal common cavities. Of the 193 GER episodes, 159 (82%) were associated with transient lower esophageal sphincter relaxation (TLESR). TLESRs were significantly longer in duration than single swallows (15.1 seconds vs 5.6 seconds, P < .001) and had lower nadir pressures (0.8 mm Hg vs 2.3 mm Hg, P < .001). A total of 3216 esophageal body pressure waves were analyzed; 70% of swallow-induced pressure waves were peristaltic in sequence compared with 5% of swallow-unrelated pressure waves. During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure wave sequences. In healthy preterm infants, TLESRs are the predominant mechanism underlying GER, and esophageal clearance mechanisms are well developed by at least 31 weeks' postmenstrual age.

Intersubject and interswallow variability in topography of esophageal motility.

Topographic plots linking averaged manometric data in time and space suggest that sequential contraction segments form esophageal peristalsis. A system capable of plotting individual swallows was developed to verify this observation and to determine intersubject and interswallow variability in their topographic appearance. Fourteen volunteers were studied with a novel computerized assimilation method capable of generating topographic contour plots as well as conventional wave forms for analysis. Contraction segments in the proximal body and lower sphincter were identified in all subjects as being separate from the remainder of the esophagus with little interswallow variation. The appearance of peristalsis through the distal body was more variable because of its intermittent separation into two dominant contraction segments (59.8% of swallows) that had poorly correlated contraction strength (median r = 0.15). Intersubject variability exceeded interswallow variability in topographic landmarks, resulting in distinctive topographic "fingerprints" of peristalsis for each subject. We conclude that topographic plotting of single swallows is feasible and confirms the presence of sequential contraction segments in the esophagus. Interswallow variability helps demonstrate two segments within the smooth-muscle body, an anatomical region of seeming homogeneity, that have sufficient contraction independence to indicate separate neuromuscular units responding to different contractile influences.

Effects of systemic hyperoxia on eustachian tube ventilatory function.

Middle ear negative pressure and effusions, decreased middle ear compliance, and abnormal tympanometry results have been described after diving on oxygen. Middle ear gas hyperoxia has been shown to down-regulate the eustachian tube ventilatory function (ETVF). The purpose of the present study was to investigate to what extent systemic hyperoxia in the face of air-equivalent middle ear gas composition might interfere with the ETVF. ETVF was investigated in four young adult female cynomolgus monkeys by the forced-response and inflation-deflation tests using air while the animals breathed either room air or 100% normobaric oxygen. Higher opening, closing, and steady-state pressures were observed under systemic hyperoxia. The percentage of the applied pressure equalized, and the maximal pressure change on a single swallow in the deflation test were both lower under hyperoxic conditions. The results show that systemic hyperoxia might impair ETVF. This observation adds to our understanding of the pathophysiology of middle ear dysfunction observed after diving on oxygen.

Characterisation of relaxation of the lower oesophageal sphincter in healthy premature infants.

Gastro-oesophageal reflux disease causes significant morbidity in premature infants, but the role of dysfunction of the lower oesophageal sphincter (LOS) in this condition is unclear. Oesophageal manometry was performed after gavage feeding in 13 healthy preterm neonates (postmenstrual age > or = 33 weeks) with a perfused sleeve with side hole assembly. Swallow related (both single and multiple) and transient LOS relaxations (TLOSRs) were identified and the characteristics of these events defined. Reflux was identified with manometric criteria (common cavity episodes). Five hundred and eleven relaxation of the LOS were observed, 55% related to single swallows, 23% related to multiple swallows, and 22% TLOSRs. The time to maximal LOS relaxation was longer for TLOSRs than for single or multiple swallows (mean (SEM) 5.0 (0.3) s v 3.0 (0.1) s and 3.3 (0.1) s, p < 0.0001 and p < 0.005). The durations of multiple swallows and TLOSRs were longer than single swallows (12.2 (0.5) s and 11.2 (0.4) s v 5.3 (0.2) s, p < 0.0001). Most of the oesophageal body common cavity episodes (94%) occurred during TLOSRs. In healthy preterm infants (postmenstrual age > or = 33 weeks) the motor events associated with LOS relaxation were similar to those seen in healthy adults. TLOSRs may be an important mechanism of reflux in premature infants.

Quantitative assessment of swallowing in healthy adults

Swallowing has hitherto been evaluated during physical examination, radiologic barium studies, manometry, and cervical auscultation. Radiography principally demonstrates qualitative aspects of oral and pharyngeal function, whereas quantitative aspects have primarily been documented by manometry. To evaluate swallowing quantitatively, without using invasive methods or radiation, we have applied a combined test of water drinking, i.e., the Repetitive Oral Suction Swallow test (ROSS). The test provides reliable measurements of suction pressure, bolus volume, timing of important events in oral and pharyngeal swallow, and respiration. The test is described and results from 292 healthy, non-dysphagic subjects are presented. We found a mean bolus volume of 25.6 +/- 8.5 ml during single swallow and 21.1 +/- 8.2 ml during stress (forced, repetitive swallow). During forced, repetitive swallow, the bolus volume was more strongly associated with suction time (r2 = 0.55) than with peak suction pressure (r2 = 0.04), indicating that suction time is more important than suction pressure in determining the bolus volume. The oral-pharyngeal transit time decreased: single swallow 0.56 +/- 0.36 sec, forced repetitive swallow 0.23 +/- 0.11 sec, as did the coefficient of variation (48% and 64%, respectively) indicating a more automatic neural process for pharyngeal function in forced, repetitive swallow. The postswallow respiration started with inspiration in 10% of studied individuals, but did not correlate with deviations in other variables in the test. Thus, postswallow inspiration must be considered as normal. The ROSS test offers a rapid and easy quantitative assessment of swallowing.

Esophageal clearance scintigraphy, in diabetic patients--a preliminary study.

The aim of this preliminary study was to evaluate the predictive value of esophageal clearance scintigraphy (ECS) in the diagnosis of esophageal autonomic neuropathy in diabetic patients without any esophageal symptoms. A single swallow ECS was performed in 12 diabetic patients and 15 normal volunteers, and esophageal transit time (ETT) and esophageal (Es) T 1/2 values were calculated. ETT and Es T 1/2 were found to be significantly prolonged in the diabetic group (p less than 0.01 and p less than 0.05, respectively). In this preliminary study, our results strongly suggest that ECS may be an important noninvasive diagnostic tool in the evaluation of diabetic patients with asymptomatic esophageal autonomic neuropathy.

Parametrische Ösophagusszintigramme von Passageuntersuchungen in Mehrfachschlucktechnik: Vergleich einer neuen Methode mit einem StandardÖsophagustransittest

Established single-swallow techniques for the assessment of oesophageal motility disorders encompass a high potential of falsely positive/negative findings caused by the considerable variability between single swallows. In this study, therefore, a new form of parametric oesophageal scintigraphy (POeS) is introduced which allows simultaneous assessment of 15-20 consecutive swallows. To assess the value of this combined qualitative/semiquantitative method 166 patients with various oesophageal motility disorders were tested in an intraindividual comparison with a standard oesophageal transit test (OeTT). In contrast to OeTT, POeS yields specific image patterns which permit a differentiation between various forms of peristaltic disorder. By the use of POeS the bolus behaviour during its oesophageal passage is well characterized, the main location of the functional disorder can be identified and a correct classification of the severity can be achieved as well. In contrast to OeTT, diagnosis in POeS is based on a series of consecutive swallows. Misinterpretation due to possible variations between single swallows is often observed in OeTT, providing up to 30% false-positive and 52% false-negative findings which are almost eliminated using POeS.

Reproducibility of oesophageal transit studies: several 'single swallows' must be performed.

The 'single swallow' technique for the isotopic investigation of oesophageal function has been widely accepted. In our experience the results obtained when several consecutive 'single swallow' tests are performed show considerable variation. Although one or two swallows may be enough to diagnose abnormality, the exclusion of a motility disorder requires more, preferably six consecutive swallows.

An ultrasound examination of tongue movement during swallowing.

Six female adults were studied during the production of four single swallows each, using real-time ultrasound. A pellet was affixed to the tongue at the junction between the (calculated) anterior third and posterior two-thirds of the tongue surface. Direction, rate, and extent of pellet movement were measured and used to create stages of tongue blade movement during swallowing. Pellet movement was then compared to the three stages of hyoid movement (ascent, steady, descent). Anterior-posterior and superior-inferior components of pellet movement were examined and discussed.

Relationship of Transient Lower Esophageal Sphincter Relaxation tai Post randial Gastroesophageal Reflex and Belching in Dogs

Methods have been developed for the recording of patterns of motor function associated with spontaneous gastroesophageal reflux and belching in trained, unsedated dogs. Pharyngeal, esophageal body, lower esophageal sphincter (LES), and gastric pressures were monitored in 3 dogs with a manometric assembly inserted through a cervical esophagostomy. Spontaneous changes in esophageal pH were recorded simultaneously with a glass electrode. Each dog was studied three times for 3 h starting directly after completion of a full-sized meal. Acid reflux was recorded on 40 occasions; on 35 of these occasions it was possible to analyze, in detail, motor events at the time of reflux. This analysis showed that the LES was completely relaxed at the time of reflux and that the relaxation occurred within the 15 s before the onset of esophageal acidification. In 77% of the reflux episodes LES relaxation occurred independently of swallowing or any other motor event. The remainder of the LES relaxations associated with reflux were secondary to a swallowing salvo or a single swallow that did not trigger an esophageal body peristaltic wave. Straining was associated with reflux during many episodes of LES relaxation, but did not induce reflux if there was measurable LES pressure. Belching was also related to complete LES relaxations with a pattern identical to that associated with acid reflux. In the dog, liquid and gas reflux occurred during transient LES relaxations that were very similar to those that allow reflux to occur in humans. The dog is a suitable model for investigation of the nature and control of reflux associated with transient LES relaxation.

A tongue pellet for use in ultrasound imaging

A 5‐mm stainless steel ball bearing was affixed to the tongue using dental impression material and imaged visually with real time ultrasound. The pellet was used to measure movement at a single point on the tongue surface during speech and swallowing gestures. The pellet was placed at midline, a measured distance posterior to the tongue tip. Methodological validation of the visibility and positioning of the pellet was determined from phantom measurements. Pellet movements during speech were found to define superior/inferior and anterior/posterior tongue movements. Our data suggest, however, that these movements do not always represent the point of maximum interest on the tongue surface. Measurements made during swallowing indicate that for both single swallows (20 cc H2O) and continuous swallows pellet movement over time contains transverse and longitudinal wave components. Greater tongue excursion occurred during continuous swallowing. The advantages and limitations of using a pellet will be discussed. Future applications will be mentioned.

Analysis of tongue motion during swallowing using real-time ultrasound visualization

Because real-time ultrasound provides an excellent method to visualize the soft tissue structures of the tongue during speech, this technique was applied to analyze the oral and pharyngeal stages of swallowing. Eight normal subjects (ages 19–26, x̄ − 22.7] and one patient with a neurologic disease were subjects. Sagittal ultrasound scans of the tongue were obtained while subjects swallowed 5 cc of water in single swallows. Measurements were made of mid-tongue thickness at rest and during swallow, tongue length, sequence and timing of bolus movement, and tongue activity during swallow. Comparison of data for the normal and impaired subjects will be presented along with a discussion of the stages of swallowing. The results will be discussed with respect to neuromuscular theory and standard radiologic techniques.

Daily measurements of variation in weight loss of eggs of seven passerine species before and during natural incubation

The eggs of one or more clutches of seven passerine species were weighed each day from the day they were laid until hatching. In all seven, the rate of weight loss increased during incubation. This increase was more rapid in the early stages, leading to curvilinear regression. Linear regression was, however, highly significant and explained over 80% of the variation in four species. Curvilinear regression was significant in two other species. The weight loss curve of a single unfertilized Barn Swallow, Hirundo rustica, egg was similar to that of the rest of the clutch until they commenced to pip. The daily weight loss of five unincubated eggs also increased with time. Shell damage was suspected to be the cause of sudden increases in weight loss of individual eggs. A simultaneous drop in weight loss by six clutches was probably caused by high humidity. Other decreases in weight loss may have been caused by rain. Mean weight loss from water vapour conductance through the shell as a percentage of initial egg weight was 0.9 ± 0.08 during the laying period, 12.0 ± 0.72 during the laying period plus the incubation period prior to pipping, and an estimated 14.6 ± 0.85 for the laying period and the whole incubation period.

Oesophageal and diaphragmatic activity during sucking in lambs.

1. Buccal, pharyngeal, oesophageal and diaphragmatic movements during swallowing of saliva and sucking from a bottle were studied in lambs by recording electromyograms (e.m.g.s) from the mylohyoid, thyrohyoid and thyroarytenoid muscles, cervical and caudal thoracic oesophagus and vertebral and costal regions of the diaphragm. Buccal and pleural pressure recordings were also made.2. Swallows of saliva characteristically involved contraction of the mylohyoid followed sequentially by contraction of the thyrohyoid, cervical, and finally, caudal thoracic oesophagus.3. Sucking (indicated by the mylohyoid e.m.g.s and buccal pressure) was initially at rates up to 6 sec(-1), sustained at up to 4 sec(-1) for 30-45 sec and, once established, accompanied by swallows in a 1:1 association with sucking.4. Respiration ceased during the pharyngeal phase of swallowing. At the time the primary contraction (of swallowing) involved the caudal thoracic oesophagus vertebral fibres of the diaphragm forming the hiatus oesophageus became quiescent, although costal fibres continued to contribute to inspiration.5. During sucking, respiration was shallow and rapid, with diaphragm contractions sandwiched between swallows.6. Towards the end of an episode of sucking, contractions of the diaphragm became more intense and occurred in groups with pressure changes corresponding to both individual contractions and the grouped activity.7. Primary oesophageal contractions occurred only after single swallows or at the end of a series of swallows.8. During periods when sucking and swallowing were frequent, short episodes of oesophageal contraction occurred, each being between thyrohyoid contractions.9. Recording from contiguous sites of the caudal thoracic oesophagus confirmed a caudally progressive character of those short contractions of the oesophagus observed during sucking.10. Factors contributing to these changes in oesophageal activity and consequences of altered diaphragmatic activity in sucking have been discussed.

Esophageal scintigraphy to quantitate esophageal transit (quantitation of esophageal transit)

None of the tests employed currently to investigate esophageal transit is quantitative. The purpose of this study was to evaluate normal subjects and patients with a variety of esophageal disorders using a scintigraphic technique to quantitate esophageal transit. After oral administration of a bolus of water labeled with 99mTc-sulfur colloid, isotopic count rates were measured over the esophagus employing a gamma-camera on line to a digital computer. Esophageal transit was expressed as the percent emptying for each of the first 15-sec after the initial swallow and for 15-sec intervals after serial swallows. Sixty-two subjects were studied, including: normal volunteers; patients with motor disorders of the esophagus such as achalasia, diffuse esophageal spasm, and scleroderma; and patients with symptomatic gastroesophageal reflux both with and without esophageal motor dysfunction on manometic testing. Esophageal transit was decreased significantly after single and multiple swallows in patients with motor disorders of the esophagus. In addition, esophageal transit was abnormal in patients with reflux disease accompanied by abnormal motor function. In contrast, esophageal transit was normal after a single swallow, but incomplete after serial swallows in patients with reflux associated with normal esophageal motor function on manometry. We conclude that esophageal scintigraphy may be used to evaluate esophageal transit.

A Comparison of Gastroscopic and Roentgen Findings

THE flexible gastroscope has opened a new field in gastric diagnoses. In most cases it is safely and easily introduced and allows excellent visualization of the gastric mucosa in the living person. We have had three gastric perforations, all occurring during the use of instruments equipped with the spherical sponge tip devised by Henning. Experimental evidence indicates that the friction of this tip was responsible for these non-fatal accidents (9). No accidents have occurred when the long-finger guide was used. Lesions obstructing the esophagus and cardiac end of the stomach, aortic aneurysm, and suspected esophageal varices are contraindications to gastroscopy. Although most gastroscopists check their findings with roentgen findings, few radiologists check with the gastroscopist. Schatzki (8), Ansprenger (1), and Jutras (6) have made such comparisons. From 1926 to 1934 Sielman and Schindler made roentgenographic relief studies of the stomach in more than 4,000 cases. Of these cases, several hundred were gastroscoped. Since September, 1934, over 800 gastroscopies have been performed at the University of Chicago Clinics, most of these cases having been examined by Dr. Templeton by roentgen relief methods either before or after he had seen them gastroscopically. Gastroscopic and roentgenologic examinations should be considered as cooperative rather than competitive examinations. Either method may visualize lesions that the other cannot. Shape, contour, motor function, and gross lesions are better seen roentgenologically, while mucosal changes and smaller lesions are better seen gastroscopically. In some cases the roentgenologic examination is sufficient for accurate diagnosis. Gastroscopic Appearance of the Normal Stomach In the normal stomach, differences between the gastroscopic and the roentgenographic appearance are quite striking. Before the introduction of air the gastroscopist sees rather prominent, irregular, parallel folds which apparently do not correspond with the rugæ. This appearance of the collapsed mucosa presumably has nothing to do with its thickness and may or may not be of clinical significance. On distention with air these folds flatten easily and there appear in the body from 10 to 14 parallel folds, many of which are irregular, bifurcated, and traversed by cross rugæ (Fig. 1). Rugæ are rarely seen in the antrum, but a high-twisted cord-like structure separates the antrum from the body of the stomach. This fold, the musculus sphincter antri (Fig. 2), usually cannot be identified with certainty at roentgenologic examination. Roentgen-Ray Appearance of the Normal Stomach (A). After a single swallow of barium. — variety of patterns may be seen (Figs. 3–6). Not uncommonly there are from four to six roughly parallel folds in the body and the antrum, and occasionally the antrum contains in addition one or more oblique folds. (B). After filling the stomach with barium and then compressing it.