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Biomedical subjects

W C Orr

Publications and source records attributed to W C Orr.

At least 91 records · Page 5Linked to original sources
PubMed1989

Lower esophageal sphincter pressure, esophageal body motor functioning, and esophageal acid sensitivity.

Esophageal acid sensitivity is believed to develop as a result of esophageal acid exposure, contributing factors being gastroesophageal reflux and delayed esophageal acid clearance. The relationship among lower esophageal sphincter pressure, motor functioning of the body of the esophagus, and esophageal acid sensitivity was examined by comparing the results from 912 patients and normal subjects studied with both esophageal manometric and Bernstein acid infusion tests. Positive acid infusions were statistically more closely associated with hypotensive lower esophageal sphincter pressures than with any motor abnormality in the body of the esophagus. Of the several esophageal body motor abnormalities considered, only feeble peristalsis had significantly more positive Bernstein tests than did normal esophageal body motor functioning. The findings from this study demonstrate that hypotensive lower esophageal sphincter pressure is more closely associated with an acid-sensitive esophagus than is impaired esophageal body motor functioning.

Esophagitis↗
PubMed1988

Anorectal functioning in fecal incontinence.

Manometric testing was performed on three groups of subjects: 14 patients complaining of fecal incontinence, 14 age- and sex-matched continent patients, and 14 sex-matched younger normal controls. The younger group displayed significantly stronger contractions of the external anal sphincter and puborectalis than the two patient groups, which did not differ. No differences were found in the relaxation of the internal and sphincter. The incontinent group required a significantly larger stimulus in order to detect rectal distension compared to either the continent patients or the younger normals. An additional group of unmatched normals and incontinent patients demonstrated significant differences in their ability to retain rectally infused saline. The patients leaked sooner and retained less; however, the performance of the normals was considerably reduced from that reported in previous studies. The aging process seems to result in weakening of the striated muscles of the anal canal, although fecal incontinence need not occur. The afferent limb of the anorectal sensorimotor mechanism does not necessarily deteriorate with aging. A lower threshold for sensation of rectal distension among continent individuals apparently helps them to avoid incontinent episodes, even though maximum contractile pressures in their anal canal are no different from a comparable group of incontinent individuals.

Adult↗
PubMed1988

Esophageal acid clearance during sleep in patients with Barrett's esophagus.

Sleep-related gastroesophageal reflux and esophageal acid clearance have been shown to be important components in the pathogenesis of reflux esophageal disease. Previous studies have suggested that patients with more severe esophagitis are distinguished by an accumulation of acid mucosal contact time during sleep. These data would suggest that patients with Barrett's esophagus should have particularly severe impairment of acid clearance, most notable during sleep. To address this issue, 16 asymptomatic healthy volunteers and 13 patients with Barrett's esophagus were studied. Acid clearance was assessed by timing the reestablishment of an esophageal pH of 4 following the infusion of 15 ml 0.1 N HCl. Sleep was polygraphically monitored in order to objectively determine sleep and waking. The results indicated that while patients with Barrett's esophagus had a marked increase in the frequency of spontaneous gastroesophageal reflux during sleep, they unexpectedly demonstrated faster acid clearance times during both waking and sleep. A greater percentage of arousal responses to acid infusion during sleep was noted in the Barrett's group. It is concluded from these results that patients with Barrett's esophagus can adequately clear acid from the distal esophagus but experience considerable acid mucosal contact through repeated episodes of spontaneous reflux during sleep.

Adult↗
PubMed1988

The effect of a modified functional appliance on obstructive sleep apnea.

This study combined the use of cephalometrics and overnight polysomnographic monitoring to analyze the effects of a modified functional appliance on airway, sleep, and respiratory variables in patients with obstructive sleep apnea (OSA). Twelve patients without overt anatomic or pathologic evidence of obstruction were selected on the basis of an initial single night of polysomnographic monitoring, which confirmed the diagnosis of obstructive sleep apnea syndrome. The patients subsequently were fitted with a modified functional appliance designed to securely hold the mandible in an anterior-inferior position. A subsequent overnight polysomnographic study was obtained with each patient wearing the appliance. Lateral cephalometric radiographs with and without the appliance in place were also obtained. The mean vertical and horizontal changes in mandibular position while wearing the appliance were 8.49 mm and 2.28 mm, respectively. The findings indicate that 10 of the 12 patients had decreases in the rate of complete airway obstructions from a mean of 28.86 to 18.69 events per hour, and in the total apnea index from a mean of 53.81 to 35.99 events per hour. A reduction in the rate of obstructive events is attributed to the effect of the appliance on the oropharyngeal structures. Six cephalometric measurements are presented to provide a means of assessing effects of the appliance on the oropharynx and associated structures. The modified functional appliance is a conservative, successful treatment alternative that could benefit patients with obstructive sleep apnea syndrome.

Activator Appliances↗
PubMed1988

Water swallows versus food ingestion as manometric tests for esophageal dysfunction.

Data from 100 consecutive patients with chest pain or dysphagia, or both, who underwent esophageal testing with standard water swallows and upright food ingestion were retrospectively evaluated. In addition to having manometric patterns monitored, patients were asked to relate symptoms during testing. Of 77 patients with a history of dysphagia, significantly more had abnormal manometry during the test meal than with water swallows (79 vs. 43%, p less than 0.005). Additionally, dysphagia, although reported in only 8% of these patients during standard testing, occurred in 47% during the test meal (p less than 0.001). Of 60 patients with chest pain, symptoms were rarely reported (5%) with water or with food ingestion. We conclude that manometry with food ingestion should be used as a provocative test in anatomically normal patients with dysphagia.

Adult↗
PubMed1988

Dose--response effect of famotidine on patterns of gastro-oesophageal reflux.

The present study attempts to assess the alteration in patterns of gastro-oesophageal reflux as assessed by 24-h oesophageal pH monitoring by varying degrees of H2-receptor blockade with famotidine. Subjects were 12 patients with complaints of daily heartburn who demonstrated at least 6% of acid mucosal contact time by 24-h ambulatory oesophageal pH monitoring. All subjects had a positive Bernstein test, and nine of the 12 subjects had erosive oesophagitis. The study was conducted as a double-blind crossover design utilizing 40 mg nocte, 20 mg b.d., and 40 mg b.d. and placebo treatments. Results indicated that all treatments significantly reduced the 24-h percentage acid contact time (P less than 0.05) compared to placebo. The two b.d. treatment regimens also significantly (P less than 0.05) reduced the number of episodes lasting longer than 5 min. Only the b.d. regimens successfully lowered the percentage of upright acid exposure. All treatments significantly (P less than 0.01) reduced the percentage of supine acid contact time, as well as the number of episodes lasting more than 5 min. It is concluded that gastro-oesophageal reflux disease may well require a b.d. dosing regimen with famotidine in order to achieve optimal mucosal healing and day time symptom control.

Adult↗
PubMed1988

The timing of evening meal and ranitidine administration--effects on patterns of 24 hour intragastric acidity.

Intragastric pH-metry was utilized to assess the effect of the time of meal ingestion and ranitidine administration on 24-h intragastric acidity. Twelve volunteers with a documented history of duodenal ulcer were studied in a four-way crossover design. Subjects randomly received ranitidine at 18.00 and 22.00 hours, with and without food. Serial blood samples were collected and analysed for ranitidine by high pressure liquid chromatography. Over the interval of 18.00-0.700 hours, the mean hydrogen-ion activity was significantly lower with the 18.00 hour dose than with the 22.00 hour dose (P less than or equal to 0.05). There were no differences between the four treatments in median pH or mean hydrogen-ion activity over the 23-h study interval. There were no differences between treatments in peak ranitidine concentrations, time to peak concentration, area under the serum-concentration time curve or elimination half-life.

Adult↗
PubMed1988

Validation of an ambulatory esophageal pH monitoring system.

The present study documents the accuracy of a commercially available ambulatory esophageal pH instrument. The distal esophagus of five subjects with daily heartburn was monitored for 24 h in the laboratory via an antimony pH electrode. The computer output from the ambulatory unit was compared to the on-line recording in terms of all events in which the pH dropped below four. A signal detection model was used, with an on-line pH tracing serving as the criterion response. The events noted as true positives (80%) were an accurate representation by the computer output of the events of pH less than four displayed by the on-line recording. The processing done by this particular ambulatory system tends to actually "ignore" transient pH drops (18% false negatives) and, may, in fact, provide more physiologically meaningful information than hardwired analog techniques for 24-h pH monitoring. The results confirm that ambulatory pH monitoring can produce meaningful and reliable physiological data concerning gastroesophageal reflux.

Adult↗
PubMed1987

Effect of cleft palate repair and pharyngeal flap surgery on upper airway obstruction during sleep.

The effect of von Langenbeck palatoplasty and pharyngeal flap surgery on upper airway obstruction during sleep was studied by obtaining polysomnographic sleep studies on 10 patients undergoing each procedure at 1 to 2 days prior to surgery, 2 to 3 days postoperatively, and approximately 3 months postoperatively. The effects of von Langenbeck palatoplasty on sleep-related upper airway obstruction were usually minimal and clinically insignificant, whereas severe obstructive sleep apnea was present in all but one of the patients undergoing pharyngeal flap surgery at 2 to 3 days postoperatively. In most patients the upper airway obstruction was resolved at the 3-month postoperative sleep study. These data suggest that palatoplasty carries with it a very slight risk of upper airway obstruction, whereas pharyngeal flap surgery has as a very frequent concomitant the occurrence of severe obstructive sleep apnea in the immediate postoperative period.

Adolescent↗
PubMed1987

Comparison of calcium channel blocking agents and an anticholinergic agent on oesophageal function.

The effects of oral doses of three calcium blockers and an anticholinergic drug on oesophageal function were compared. Nifedipine (20 mg) and hyoscyamine (0.25 mg) significantly reduced lower oesophageal sphincter (LES) pressure and oesophageal contractile pressure. Verapamil (120 mg) and diltiazem (60 mg) had no significant effect on any of the oesophageal variables measured. Oesophageal transit time and oesophageal contractile duration were not affected significantly by any of the agents. Only hyoscyamine significantly prolonged acid clearance time. The combination of nifedipine and hyoscyamine was no more effective in decreasing LES pressure or oesophageal contractile pressure than either agent alone. Either nifedipine or hyoscyamine would appear to be potentially effective for the treatment of oesophago-spastic and other hypertensive motor disorders, but hyoscyamine may lead to prolongation of acid clearance from the oesophagus.

Adult↗
PubMed1987

Do endoscopic findings influence response to H2 antagonist therapy for gastroesophageal reflux disease?

As part of a multicenter trial evaluating ranitidine in the treatment of gastroesophageal reflux disease, the therapeutic responses of patients with and without abnormal endoscopic findings were evaluated. All patients were randomized to either placebo or ranitidine (150 mg bid) treatment groups. The treatment interval was 6 wk. Thirty-seven percent of 283 patients enrolled in the trial had normal baseline endoscopy. Compared to the placebo group, 147 evaluable ranitidine patients with abnormal endoscopy displayed a marked and rapid symptom reduction which was sustained throughout the last 4 wk of therapy. Despite randomization of endoscopically normal patients, those treated with ranitidine had significantly more heartburn at baseline. However, the 89 evaluable ranitidine-treated patients with normal endoscopy also experienced a marked and rapid reduction in heartburn at the end of 1 wk. The symptomatic improvement in the endoscopically abnormal ranitidine patients was significantly greater (p less than 0.05) than that observed in the endoscopically normal ranitidine group. Since both groups fared better on ranitidine than placebo, the results of this study indicate that ranitidine is an effective treatment for patients with heartburn symptoms and documented esophageal acid sensitivity whether or not endoscopic parameters for esophagitis are present.

Adolescent↗
PubMed1986

Effects of maternal smoking and caffeine habits on infantile apnea: a retrospective study.

To evaluate the relationship of antecedent maternal smoking and caffeine consumption habits on the occurrence of apnea in their offspring, rates for central and obstructive apnea were analyzed in a cohort of mother-infant pairs. The mothers of 298 infants with apnea responded to a questionnaire completed prior to a nine-hour polysomnogram performed as part of the patients' evaluations. Cigarette consumption estimates were computed on a 20-cigarette per pack basis, and caffeine intake, based on dietary sources (coffee, tea, chocolate, and colas), was summarized as milligrams of caffeine consumed per day. Rates of central and obstructive apnea of 6 to 10 seconds in duration were calculated. Multiple linear regression analysis determined that smokers tended to be younger and have lower birth weight infants who presented earlier with apnea than infants of nonsmokers. Increased rates of central apnea occurred in infants of smokers as compared with infants of nonsmokers. During pregnancy, a pack per day increase in maternal smoking habit was associated with a 1.88/h increase in central apneas in their offspring (P less than .01). Maternal smoking after delivery had a similar relationship. Obstructive apnea rates were similar in both groups. Both central and obstructive apnea rates associated positively with increasing maternal caffeine consumption. Smoking habits and caffeine ingestion were correlated (P less than .01). Infants with apnea have greater rates of central apnea when their mothers smoke during pregnancy. Therefore, a history of nicotine consumption should be included in the medical history of infants presenting with apnea.

Apnea↗
PubMed1985

Diagnosis and management of obstructive sleep apnea. A multidisciplinary approach.

Snoring has been shown to be the primary sign of a potentially serious medical condition, ie, obstructive sleep apnea (OSA). Traditionally, the otolaryngologist has been the primary medical resource for patients with snoring problems. However, until recently, little was known about the now-acknowledged serious complications of this phenomenon. Of the primary treatments for this condition, those most commonly utilized to date involve surgical procedures routinely performed by the otolaryngologist, ie, tracheostomy and uvulopalatopharyngoplasty. Thus, the practicing otolaryngologist has been thrust into the forefront in the diagnosis and management of OSA. Hence, it behooves the modern practitioner to be cognizant of the multidisciplinary approach to this problem. Herein, we review snoring as a medical problem, sleep laboratory studies of patients with OSA, and the interaction of multidisciplinary team members in the optimal management of this ubiquitous problem.

Airway Obstruction↗
PubMed1985

Diagnosis and management of obstructive sleep apnea. Part II.

Snoring has been shown to be the primary sign of a potentially serious medical condition, ie, obstructive sleep apnea. Traditionally, the otolaryngologist has been the primary resource for patients with snoring problems although, until recently, little was known about the now-acknowledged serious complications of this phenomenon. Among the primary treatments for this condition, the most commonly used to-date involve surgical procedures routinely performed by the otolaryngologist, ie, tracheostomy and uvulopalatopharyngoplasty. Thus, the practicing otolaryngologist has been thrust into the forefront of diagnosis and management of obstructive sleep apnea, and it behooves the modern practitioner to be cognizant of the multidisciplinary approach to the diagnosis and management of this problem. The utilization of information obtained during the sleep study determines the management of the sleep apneic patient.

Adult↗
PubMed1985

Utilization of polysomnography in the assessment of sleep disorders.

Polysomnography is an indispensable tool in dealing with sleep disorders, but because of its inherent logistical complexity and expense, it must be used with discretion. Many sleep disorders can be diagnosed clinically by the astute physician and treated empirically with good results. On the other hand, there are numerous circumstances in which the best clinical judgment indicates a polysomnographic evaluation. The ubiquity of sleep complaints in medical practice, and the knowledge that they may in some instances be associated with life-threatening medical complications, compel the modern clinician to obtain a basic knowledge of the appropriate utilization of the sleep laboratory. Polysomnography is a useful adjunct to the clinician because it provides objective information to be integrated into the overall clinical picture in the evaluation of the patient's complaint. Polysomnography should be utilized in cases where the results will clearly make a difference in the differential diagnosis or in the treatment plan. If a clinician's basic approach to the evaluation of the patient or his treatment will not be substantially altered by polysomnography, it should not be undertaken. The results of polysomnography should give the referring physician critical information concerning the type of disorder, its severity, appropriate treatment and necessary follow-up. Unfortunately, few, if any, hard and fast rules exist concerning the appropriate utilization of polysomnography. As always in medicine, the physician must take a careful history, and integrate it with other basic laboratory tests and the physical examination, and then decide whether polysomnography will provide useful additional information. The ability to assess physiological phenomena during sleep objectively has clearly advanced the study of sleep disorders to the point that it is now considered an integral part of internal medicine. Polysomnography has made available the objective study and documentation of sleep disorders which, coupled with increasing sophistication concerning the natural history of sleep disorders, have created a new and exciting discipline in clinical medicine.

Cost Control↗
PubMed1985

Progesterone levels and sleep-related breathing during menstrual cycles of normal women.

The respiratory stimulant effect of progesterone has been known for many years and has led to the hypothesis that this hormone protects young, premenopausal women from disordered breathing and apnea during sleep. Therefore, sleep, breathing, and gonadal hormone parameters were evaluated for 11 normal, menstruating women during times of high and low progesterone levels. No sleep or breathing parameter changed significantly with varying levels of progesterone. Although normal women show a significant change in progesterone levels across the course of the menstrual cycle, the levels achieved did not produce significant changes in breathing parameters.

Adult↗