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W J Dodds

Publications and source records attributed to W J Dodds.

At least 37 records · Page 2Linked to original sources
PubMed1993

Normal laryngeal valving patterns during three breath-hold maneuvers: a pilot investigation.

Synchronized videonasendoscopy and respiratory recordings were conducted in six healthy male subjects to evaluate activity of the arytenoid cartilages, true vocal folds, false vocal folds, and epiglottis during repeated trials of three breath-hold maneuvers: EASY hold, INHALE HARD hold, and INHALE/EXHALE HARD hold. Five of the six subjects demonstrated maximal laryngeal valving on the HARD breath-hold conditions. One subject showed maximal laryngeal valving on the EASY hold condition, and rarely demonstrated any medial displacement or contact of the laryngeal valves on either effortful breath-hold maneuver. Arytenoid approximation and true vocal fold closure were produced consistently by the majority of subjects on all breath-hold maneuvers, but false vocal fold approximation and anterior arytenoid tilting were accomplished by the majority of subjects only during the effortful breath-hold conditions. Intratrial and intersubject variation indicated that presence or degree of laryngeal valving cannot be assumed during a breath-hold maneuver. We conclude that videonasendoscopy has merit in assessing a patient's laryngeal valving ability and progress in effectively using a breath-hold maneuver for safe swallowing function.

Adolescent↗
PubMed1993

Determinants of intrabolus pressure during esophageal peristaltic bolus transport.

Previous manometric studies of esophageal fluid bolus transport in humans have generally ignored the hydrodynamic distinction between intrabolus pressure and pressure within the lumen-occluded, contracting esophageal segment. In this study we obtained concurrent esophageal videofluoroscopic and intraluminal manometric recordings in supine normal volunteers using different bolus volumes and viscosities and abdominal compression. Intrabolus pressure increased with bolus volume, viscosity, and abdominal compression. Esophageal diameter increased with larger bolus volumes, and this increase was correlated with increases in intrabolus pressure. Intrabolus pressure was highest in the bolus tail. Peak intraluminal pressures > 20 mmHg above basal intrabolus pressure almost invariably were associated with effective peristalsis, whereas values of this pressure differential < 20 mmHg frequently were associated with ineffective peristalsis and retrograde bolus escape. Intrabolus pressure can serve as an important indicator of the forces resisting peristaltic transport and the occurrence of ineffective bolus transport.

Abdomen↗
PubMed1993

Effect of aging and bolus variables on pharyngeal and upper esophageal sphincter motor function.

Effect of aging, bolus volume, temperature, and consistency on the pharyngeal peristalsis, as well as the effect of aging on the upper esophageal sphincter (UES) resting pressure and its response to esophageal distension by air and balloon, were studied in 14 young and 12 healthy elderly volunteers. In both age groups there was no significant volume or temperature effect on amplitude, duration, or velocity of the pharyngeal peristalsis. Compared with water swallows, mashed potato swallows resulted in a significant increase in the amplitude and duration of the hypopharyngeal peristaltic pressure wave (P < 0.05). For water swallows, the amplitude and duration of the peristaltic pressure wave in the hypopharynx were significantly increased in the elderly compared with the young group (P < 0.01). UES resting pressure in the elderly measured 43 +/- 5 (SE) mmHg and was significantly less than that of the young (71 +/- 8 mmHg; P < 0.01). Magnitude of the UES pressure decrease because of esophageal distension by air, as well as magnitude of its pressure increase because of esophageal balloon distension, was similar among young and elderly. 1) Contrary to common expectations, the parameters of the pharyngeal peristaltic pressure wave do not deteriorate in the elderly in their seventh and eighth decade. 2) Compared with the young, hypopharyngeal pressure wave amplitude and duration are significantly increased in the elderly. This increase could be caused by an adaptation response to a pharyngeal outflow compromise. 3) Pharyngeal peristaltic pressure wave amplitude and duration, but not its velocity, are modulated by the bolus consistency. This modulatory mechanism is preserved in the elderly. 4) Although UES resting pressure is significantly decreased in the elderly, its pressure response to esophageal distension by air and balloon is preserved.

Adult↗
PubMed1993

Pharyngeal, esophageal, and proximal gastric responses associated with vomiting.

The motor activities of the pharynx, esophagus, and proximal stomach associated with vomiting were characterized and quantified in 25 awake chronically instrumented dogs. These motor events were correlated temporally with motor responses of the gastrointestinal and respiratory tracts. Vomiting was stimulated by apomorphine or UK-14304, and motor activities of striated and smooth muscles were recorded by electromyography and strain-gauge transducers, respectively. We found responses that began 1) before retching: increased swallow frequency, relaxation of the lower esophageal sphincter (LES) and proximal stomach, and tonic contraction of the cricopharyngeus and cervical esophagus; 2) during retching: rhythmic relaxation and contraction of the pharynx and cervical esophagus 180 degrees out of phase with retching; and 3) during vomitus expulsion: relaxation of the pharynx and cervical esophagus but strong contraction of the geniohyoideus and a retrograde contraction of the cervical esophagus and pharynx. The increased pharyngoesophageal tone occurred in an all-or-none fashion independent of vomiting or the gastrointestinal correlates of vomiting. Cervical vagal blockade increased swallow frequency but did not alter the other pharyngoesophageal responses associated with vomiting. We concluded that the motor events of the pharynx and esophagus play a significant role in gastrooral evacuation during vomiting and that these motor events (except LES relaxation) are not controlled by subnodose vagal pathways.

Adrenergic alpha-Agonists↗
PubMed1993

Prevention of barium aspiration during videofluoroscopic swallowing studies: value of change in posture.

OBJECTIVE: We investigated the frequency with which changes in the position of a patient's head or body eliminated aspiration of liquid barium during videofluoroscopic swallowing studies in patients with oropharyngeal dysphagia. We also studied factors that influenced the effect of posture on aspiration. SUBJECTS AND METHODS: The study group comprised 165 patients consecutively referred for videofluoroscopic examination of the oropharyngeal stages of swallowing in whom aspiration of barium occurred while swallowing 1, 3, 5, or 10 ml of thin liquid barium or drinking barium from a cup. When aspiration occurred, the patient changed to one of five postures (chin down, chin up, head rotated, head tilted, and lying down), selected on the basis of the specific swallowing abnormality causing the aspiration. RESULTS: Changes in head or body position eliminated aspiration of at least one bolus of barium in 127 (77%) of the 165 patients, and of all four boluses plus drinking barium from a cup in 41 patients (25%). Postural changes were less beneficial in preventing aspiration in patients with substantial language or cognitive defects or restricted head movement. CONCLUSIONS: Postural techniques can eliminate aspiration of barium of at least small volumes in most patients. Expansion of the oropharyngeal swallowing study to include the effect of various postures can be done with minimal risk of increased aspiration.

Barium Sulfate↗
PubMed1993

Effect of age and bolus variables on the coordination of the glottis and upper esophageal sphincter during swallowing.

We studied 1) the effect of age and bolus variables on a) the coordination of deglutitive vocal cord adduction and upper esophageal sphincter (UES) relaxation and b) the duration of deglutitive vocal cord adduction; 2) the effect of the presence of a manometric catheter across the UES on the deglutitive glottal function; and 3) the temporal relationship between deglutitive vocal cord closure and swallow-induced apnea. We studied 10 young (23 +/- 2 yr) and 10 healthy elderly (73 +/- 2 yr) volunteers by concurrent videoendoscopy, UES manometry, respirography, and submental surface electromyography. In both groups the onset of vocal cord adduction preceded the onset of UES relaxation, deglutitive apnea, and submental electromyogram swallowing signal. In both groups, bolus volume and temperature did not have any significant effect on the duration of deglutitive vocal cord adduction. In both young and elderly volunteers, water swallows, compared with dry swallows, significantly shortened the interval between the onset of deglutitive vocal cord adduction and the onset of UES relaxation. In conclusion, coordination between deglutitive glottal and UES function, as well as the duration of deglutitive vocal cord adduction, is preserved in the elderly. Bolus volume and temperature do not have a modulatory effect on the duration of vocal cord closure, but water swallow shortens the interval between the onset of glottal closure and UES relaxation. This shortened interval may contribute to the safety of the airway during swallowing of liquid volumes.

Adult↗
PubMed1992

Epidemiologic features of von Willebrand's disease in Doberman pinschers, Scottish terriers, and Shetland sheepdogs: 260 cases (1984-1988)

During a study period from 1985 through 1988, plasma von Willebrand's factor antigen (vWF:Ag) concentration was measured as a marker for prevalence of the von Willebrand's disease (vWD) trait in Doberman Pinschers (doberman, n = 5,554), Scottish Terriers (scottie, n = 1,363), and Shetland Sheepdogs (sheltie, n = 4,279). Significant increase in prevalence of the trait was seen in scotties and shelties during this period. In 1988, 73% of dobermans, 30% of scotties, and 28% of shelties tested had abnormal vWF:Ag concentration (less than 50% vWF:Ag). We found significant differences between breeds with respect to age and vWF:Ag concentration of clinically affected dogs at time of diagnosis. The affected dobermans were older (doberman mean age, 4.6 years; scottie mean age, 1.7 years; sheltie mean age, 1.9 years) and had higher concentration of plasma vWF:Ag (doberman mean vWF:Ag, 15%; scottie mean vWF:Ag, 0%; sheltie mean vWF:Ag, 8%). Bleeding in affected dogs of all 3 breeds was observed predominantly from mucosal surfaces and from cutaneous sites of surgery or trauma. The most common site of mucosal bleeding in scotties and shelties was oral or nasal cavity, and in dobermans was the urogenital tract. Differences in clinical manifestations of vWD in purebred dogs may reflect heterogeneous defects within the vWF gene, causing a variety of abnormalities in production, structure, and function of vWF protein. Analogous to vWD in human beings, acquired deficiencies of vWF may also contribute to the clinical variability of vWD in dogs.

Animals↗
PubMed1992

Viscosity measurements of barium sulfate mixtures for use in motility studies of the pharynx and esophagus.

Detailed viscosity measurements have been made of barium sulfate mixtures over a wide range of viscosities for use in radiography of the esophagus, stomach, and duodenum. A new methodology was developed for more accurate estimation of viscosity in non-Newtonian fluids in conventional cylinder-type viscometers. As base cases, the variation of viscosity with shear rate was measured for standard commercial mixes of e.z.hd (250% w/v) and a diluted mixture of liquid e.z.paque (40% w/v). These suspensions are strongly shear thinning at low shear rates. Above about 3s-1 the viscosity is nearly constant, but relatively low. To increase the viscosity of the barium sulfate mixture, Knott's strawberry syrup was mixed to different proportions with e.z.hd powder. In this way viscosity was systematically increased to values 130,000 times that of water. For these mixtures the variation of viscosity with temperature, and the change in mixture density with powder-syrup ratio are documented. From least-square fits through the data, simple mathematical formulas are derived for approximate calculation of viscosity as a function of mixture ratio and temperature. These empirical formulas should be useful in the design of "test kits" for systematic study for pharyngeal and esophageal motility, and clinical analysis of motility disorders as they relate to bolus consistency.

Barium Sulfate↗
PubMed1992

Esophagoglottal closure reflex: a mechanism of airway protection.

Abrupt esophageal distention occurs commonly during gastroesophageal reflux, thereby generating a circumstance favorable to esophagopharyngeal regurgitation and laryngeal aspiration of gastric refluxate. The aims of the present study were to examine the glottal response to esophageal distention by air and regional esophageal distention by a balloon. Fifteen healthy volunteers (age, 25 +/- 5 years) were studied while they were in an upright position. Using concurrent videoendoscopy and manometry, glottal and upper esophageal sphincter (UES) responses to abrupt esophageal distention by air injection (10-60 mL) and balloon distention (1.5, 2.0, and 2.5 cm) were recorded simultaneously. In addition, 6 subjects were studied with concurrent synchronized videofluoroscopy. Results showed that esophageal distention by air at a threshold volume of 10-60 mL caused vocal cord closure. The UES response to this threshold volume was variable. Volumes larger than the threshold value caused complete UES relaxation and belching. In addition to vocal cord closure, belching was accompanied by anterior movement of the glottis. On videofluoroscopy, the hyoid bone moved anteriorly in association with belching, but not with vocal cord closure without belching. Proximal esophageal distention by the balloon also provoked vocal cord closure. This response was less consistent for balloon distention in the middle and distal esophagus. It is concluded that (a) esophageal distention by either air or a balloon evokes a glottal closure mechanism, thereby suggesting the existence of an esophagoglottal reflex; (b) this reflex is elicited most easily by distention of the proximal esophagus; (c) glottal and UES responses to esophageal distention are independent from each other; and (d) the esophagoglottal closure reflex may play an important role in preventing laryngeal aspiration of acid due to gastroesophageal reflux accompanied by acid regurgitation into the pharynx.

Adult↗
PubMed1992

Alteration of the upper esophageal sphincter belch reflex in patients with achalasia.

Some patients with achalasia have been reported to develop airway obstruction from a massively air-distended esophagus, which may represent an abnormality in the upper esophageal sphincter belch reflex. When questioned carefully, 95% of our achalasia patients reported difficulty with belching. The upper esophageal belch reflex in 23 consecutive achalasia patients and 12 healthy controls was studied using an upper esophageal sphincter sleeve manometry catheter and rapid injection of 20-50 mL of air into the midesophagus. Compared with normal subjects, achalasia patients were significantly less likely to have an esophageal belch for all volumes tested and were more likely to have an increase rather than a decrease in upper esophageal sphincter pressure in response to air injection. This study systematically documents that many achalasia patients have an alteration in the upper esophageal sphincter belch reflex that may be a contributory mechanism for some of the chest and upper airway symptoms reported by some patients during acute esophageal distension.

Adolescent↗
PubMed1992

Pharyngeal (Zenker's) diverticulum is a disorder of upper esophageal sphincter opening.

Pharyngeal coordination, sphincter opening, and flow pressures during swallowing were investigated in patients with pharyngeal (Zenker's) diverticula. Fourteen patients with diverticula and 9 healthy age-matched controls were studied using simultaneous videoradiography and manometry. Pharyngeal and upper esophageal sphincter pressures were recorded by a perfused side hole/sleeve assembly. Temporal relationships among swallowing events, extent of sphincter opening during swallowing, and intrabolus pressure during bolus passage across the sphincter were measured. The timing among pharyngeal contraction and sphincter relaxation, opening, and closure did not differ between patients and controls. Sphincter opening was significantly reduced in patients compared with controls in sagittal (P = 0.0003) and transverse (P = 0.005) planes. Manometric sphincter relaxation was normal in patients. Intrabolus pressure was significantly greater in patients than in controls (P = 0.001). It is concluded that Zenker's diverticulum is a disorder of diminished upper esophageal sphincter opening that is not caused by pharyngosphincteric incoordination or failed sphincter relaxation. Incomplete sphincter opening is likely to cause dysphagia. Increased hypopharyngeal pressures during swallowing are probably important in the pathogenesis of the diverticulum.

Aged↗
PubMed1992

Oesophageal clearance of small amounts of equal or less than one millilitre of acid.

The oesophageal acid clearance time was evaluated in 10 healthy volunteers of 'small' boluses of 0.5 and 1 ml and 'minute' boluses of 0.05 and 0.1 ml 0.1 N HCl, as well as 0.1 and 1 ml 0.01 and 0.001 N HCl. Swallow rate was normalised at q 60 seconds. For 0.1 ml 0.1 N HCl, acid clearance time was also measured for swallow intervals of q 30 and 120 seconds. Acid clearance time to restore pH to 4.0 was significantly longer (p less than 0.01) for the 0.5 and 1 ml 0.1 N HCl (210 and 273 seconds, respectively) than for the 0.05 and 0.01 ml acid boluses (83 and 94 seconds, respectively). The minimum acid clearance time was 18 seconds (0.05 ml 0.1 N HCl). Acid clearance time for 0.1 N HCl was less than one minute on only two occasions. The acid clearance times were comparable when the subjects sat upright. A longer interswallow interval--that is, 120 seconds, resulted in a significantly longer acid clearance time than shorter swallow intervals (p less than 0.05). Oesophageal acid clearance time for small acid volumes averaged more than three minutes and for minute acid volumes was generally more than one minute; and acid clearance times were comparable for the supine and upright postures, while gastrooesophageal reflux episodes causing pH drops to 3-4 may last for less than 15 seconds, substantial oesophageal pH drops to less than or equal to 1.5 that persists less than 15 seconds are difficult to be attributed to true gastrooesophageal reflux.

Adult↗
PubMed1992

Nicotine stimulates esophageal peristaltic contractions in cats by a central mechanism.

The aim of the present study was to 1) characterize nicotine-induced peristalsis in the feline esophagus and 2) determine the site of action of nicotine. Experiments were done on ketamine-sedated cats. Esophageal contractions were measured using a multilumen catheter assembly system. After recording 1 degree and 2 degrees peristaltic sequences nicotine (50-100 micrograms/kg iv) was administered. Nicotine induced a peristaltic contraction through the esophageal striated and smooth muscle part of the esophagus, which was not associated with any mylohyoid electromyogram activity or pharyngeal response, although the upper esophageal sphincter did relax. Addition of either atropine (20-50 micrograms/kg iv) or hexamethonium (10-20 mg/kg iv), a peripherally acting nicotinic antagonist, did not affect the striated muscle portion of the nicotine-induced esophageal contractile response but antagonized the smooth muscle response. However, mecamylamine (0.5-1 mg/kg iv), a ganglionic antagonist that crosses the blood-brain barrier, abolished the esophageal response to nicotine. Succinylcholine (0.5-1 mg/kg iv) abolished the striated muscle response without affecting the nicotine-induced smooth muscle contractility. Finally, the nicotine-induced peristaltic sequence was abolished after bilateral cervical vagotomy. In conclusion, nicotine, administered peripherally, activates central brain stem mechanisms that mediate a peristaltic sequence through the feline esophagus.

Animals↗
PubMed1992

Mechanisms of airway protection and upper esophageal sphincter opening during belching.

The mechanisms of airway protection, upper esophageal sphincter (UES) opening, and their coordination during belching were studied with a concurrent videoendoscopic, videofluoroscopic, and manometric technique. Analysis of videoendoscopic recordings revealed that glottal function during gastric and esophageal belching was similar and consisted of vocal cord adduction resulting in closure of intoitus to trachea, followed by anterior-caudad movement of the glottis, followed by slitlike or triangular UES opening. When a belch episode was associated with an intragastric pressure increase, in addition to the above features, there was approximation of arytenoids to the base of the epiglottis before the UES opened. Duration of vocal cord closure during belches induced by 40 ml intraesophageal air injection was significantly longer than belches induced by 20 ml (P less than 0.01). Vocal cord closure preceded the UES opening invariably. Analysis of videofluoroscopic recordings showed that hyoid bone movement during belching had a distinctive pattern different from its movement during swallowing. UES opening started generally when the hyoid bone was pulled anteriorly. Anterior hyoid excursion of 0.78 +/- 0.1 cm during belching was significantly shorter than its excursion of 1.8 +/- 0.09 cm during swallowing (P less than 0.01). We conclude that glottal closure is an integral component of both esophageal and gastric belch reflexes that prevents aspiration of regurgitated material into the airway. Glottal closure mechanism during belching has two tiers of closure: 1) vocal cord closure and 2) aryepiglottic approximation. Glottal and UES functions are closely coordinated during belching, and finally, during belching, UES is pulled open after its relaxation.

Adult↗
PubMed1992

Diaphragmatic contribution to gastroesophageal competence and reflux in dogs.

Events associated with gastroesophageal reflux have been determined by concurrent diaphragmatic and esophageal body electromyography, video radiography, and manometry in four conscious dogs. Three characteristic phenomena occurred in parallel immediately before and during gastroesophageal reflux: 1) transient lower esophageal sphincter relaxation, 2) profound (99.5%) and selective inhibition of crural diaphragmatic activity, and 3) a previously unrecognized dorsal movement of the gastroesophageal junction (mean 1.3 cm) demonstrated by implanted radiological markers. The patterns associated with spontaneous acid and gas reflux were indistinguishable from those induced by gastric distension. Costolumbar diaphragmatic activity was stable up until the instant of sphincter opening, when there was a single costolumbar contraction of short duration and high amplitude. Esophageal shortening did not occur before reflux. Reflux that occurred after atropine-induced inhibition of lower esophageal sphincter tone to < 2 mmHg was intermittent and coincided with selective crural inhibition. These studies demonstrated that selective crural inhibition is a prerequisite for gastroesophageal reflux and suggest that the crural diaphragm is an important factor for the maintenance of gastroesophageal competence.

Animals↗
PubMed1992

Coordination of deglutition and phases of respiration: effect of aging, tachypnea, bolus volume, and chronic obstructive pulmonary disease.

The effects of aging, tachypnea, bolus volume, and chronic obstructive pulmonary disease on the coordination of swallowing with the phases of respiration were studied by concurrent respirography and submental surface electromyography. Study findings showed that in young healthy volunteers, during rest, there is preferential coupling of subconscious swallowing with the expiratory phase of continuous respiration. This preferential coupling of swallowing with expiration was found to increase relative to other phases of respiration during water swallows and tachypnea (P < 0.05). Respiratory phase occurrence of swallowing and postdeglutitive resumption of respiration during exacerbation of chronic obstructive pulmonary disease was found to be significantly different compared with the basal state (P < 0.05). Respiratory phase occurrence of subconscious swallowing in the elderly was found to be different from the young (P < 0.05). Position had no significant effect on the coordination of swallowing and phases of respiration. We concluded that in resting young volunteers the majority of deglutitions are coupled with the expiratory phase of swallowing. This coupling is increased in frequency by the presence of a liquid bolus and tachypnea. And finally, age and chronic obstructive pulmonary disease alter this coordination significantly.

Adult↗
PubMed1992

Myogenic mechanism for peristalsis in opossum smooth muscle esophagus.

We studied the propagation of phasic contractions initiated by tetraethylammonium (TEA, 1-10 mM), high K+ concentration (10-30 mM), and bethanechol (10(-6) to 10(-2) M) in a whole organ in vitro preparation of the opossum smooth muscle esophagus. TEA initiated phasic contractions that began at all sites along the smooth muscle esophagus and propagated in both directions with a velocity similar to that of primary peristalsis. Blockade of neural transmission by tetrodotoxin (TTX, 10(-7) M) did not prevent contraction propagation. Although a majority of contractions initiated by TEA did not propagate the full length of the esophageal specimen, with the addition of TTX most contractions initiated by TEA did propagate the full specimen length in either direction. High K+ concentration and bethanechol elicited propagated contractions similar to those initiated by TEA. We conclude that 1) a myogenic mechanism exists for propagation of contractions along the smooth muscle esophagus and 2) intramural inhibitory nerves modulate the extent of myogenic propagation in the ascending as well as descending direction. We suggest that esophageal peristalsis may occur by myogenic propagation of contractions that are normally initiated in the proximal smooth muscle esophagus by excitatory nerves. Intramural inhibitory nerves may inhibit retrograde propagation as well as mediate descending inhibition in advance of the peristaltic wave.

Animals↗