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Biomedical subjects

E R Bleecker

Publications and source records attributed to E R Bleecker.

At least 109 records · Page 6Linked to original sources
PubMed1986

Bronchoconstriction induced by distilled water. Sensitivity in asthmatics and relationship to exercise-induced bronchospasm.

We studied the ability of bronchial challenge with an ultrasonically produced, distilled water aerosol to detect airways hyperreactivity in asthmatics and also evaluated its relationship to exercise-induced bronchoconstriction. Fifteen asthmatics and 10 normal subjects inhaled, at room temperature, distilled water aerosol in increasing concentrations. On a separate day, each subject performed a standard methacholine challenge. On the third day, all asthmatics exercised on a treadmill for 6 min at 90% maximal heart rate while breathing room-temperature, dry air. Pulmonary mechanics (FEV1 and SGaw) were measured before and after each challenge. Seven of the asthmatics and all of the normal subjects did not react to challenge with distilled water. Distilled-water challenge caused a 20% decrease in FEV1 in only 53% (8 of the 15) asthmatics, whereas all of the asthmatics reacted to methacholine challenge with a 20% fall in FEV1. Thus, distilled water was not a sensitive challenge procedure for the detection of airways hyperreactivity in asthma and it cannot be used as a routine screening test. However, in the asthmatics, the response to distilled water challenge correlated significantly with the response to exercise (r = 0.81, p less than 0.001). Seven asthmatics were reactive to both exercise and water, 7 were reactive to neither exercise nor water, and 1 reacted to water but not to exercise. Cromolyn completely or partially blocked both distilled-water- and exercise-induced bronchospasm in the reactive asthmatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1986

The effect of chronic nocturnal oxygen administration upon sleep apnea.

Administration of nocturnal oxygen for 1 night to patients with obstructive sleep apnea (OSA) causes a moderate reduction in apnea frequency without improving hypersomnolence. Therefore, we administered oxygen chronically to patients with OSA to determine: whether apnea frequency would be further reduced, whether the effect of oxygen upon apnea frequency is correlated with an increased ventilatory response to hypoxia and hypercapnia, and whether hypersomnolence improves with more prolonged oxygen administration. In a single-blinded, nonrandomized trial, we compared the effects of 1 month of oxygen (4 L/min by nasal cannula) with room air (4 L/min by nasal cannula) placebo during sleep in 7 men and 1 woman with obstructive sleep apnea. During non-REM sleep, acute oxygen administration elevated the average low oxy-hemoglobin saturation during apneic events and decreased apnea frequency. These acute effects persisted during chronic oxygen administration but reverted to the preoxygen effects immediately upon discontinuing oxygen. One month of oxygen did not affect the waking ventilatory response to hypoxia or hypercapnia; however, waking PaCO2 increased from 40 +/- 1 mm Hg (mean +/- SE) after placebo to 43 +/- 1 mm Hg after oxygen (p less than 0.01). Neither subjective nor objective hypersomnolence consistently improved after 1 month of oxygen administration. We conclude that: first, oxygen has no effect upon apnea frequency beyond the period of administration, and the reduction of apnea frequency is not correlated with an increased sensitivity to chemical ventilatory stimuli. The reduced apnea frequency may be related to an increased PaCO2 stimulating ventilation during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Increased vascular pedicle width preceding burn-related pulmonary edema.

Widening of the vascular pedicle on the chest roentgenogram is a recently identified sign of increased circulating blood volume. To determine whether vascular pedicle enlargement can be detected during the initial day of burn resuscitation and whether this change correlates with the early development of pulmonary edema, we reviewed the serial chest roentgenograms of 42 patients with cutaneous burns and risk factors for inhalation injury. Although no patient had pulmonary edema at the time of vascular pedicle measurements, 18 (42.9 percent) developed this complication during the 3.3 +/- 1.5 days after injury. These patients were significantly older (p less than 0.025) and had received more resuscitative fluid (P less than 0.005) than those without pulmonary edema. Initial vascular pedicle width was similar in both groups (5.9 +/- 0.9 vs 6.0 +/- 1.0 cm) and did not change in patients without pulmonary edema (5.8 +/- 0.7 cm). Vascular pedicle width increased (6.9 +/- 1.2 cm, p less than 0.01) in patients who subsequently developed pulmonary edema, and 12 of the 13 patients who had changes exceeding +1.0 cm had this problem. Enlargement of the vascular pedicle is associated with early burn-related pulmonary edema and might provide a clinically useful predictor of this cardiopulmonary complication.

Adult↗
PubMed1986

Ventilatory control during sleep in the elderly.

This review has briefly discussed the normal control of respiration during sleep with aging. Although we still do not have a complete understanding of ventilatory control during sleep in the elderly, it is clear that disorders of ventilation during sleep are clinically important in older overweight individuals. The identification of risk factors in this group will lead to an increased awareness and diagnosis of these disorders and therefore result in the development of rational approaches to the management of these individuals.

Aged↗
PubMed1985

Inhibitability and enhanceability of basophil histamine release in asthmatic and normal subjects.

Circulating human basophils contain histamine, a potent mediator of inflammation. Previous in vitro studies have shown that histamine 'releasability' in asthmatic subjects differs from normal subjects but have not evaluated possible differences in the immunopharmacological control of the release of this mediator which might account for these differences. The purpose of the present study was to examine the immunopharmacologic control of basophil histamine release in 14 asthmatics and 10 normal subjects who were characterized by pulmonary function tests, allergic status (skin tests and serum IgE levels) and nonspecific airways reactivity to methacholine and histamine. Basophils were stimulated with anti-IgE, and the inhibitory effects of the H2 agonist, dimaprit, and dibutyryl cyclic AMP (dbcAMP), as well as the enhancing properties of 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and indomethacin on the modulation of histamine release, were investigated. Although no statistically significant differences were seen in the percent histamine release triggered by anti-IgE in these two groups, enhancement of histamine release by 5-HPETE was more consistent in the asthmatic subjects (10 of 10) than in control subjects (6 of 8). The percent increase in histamine release produced by 5-HPETE in asthmatic subjects averaged 3.9 +/- 1.3% using 0.03 micrograms anti-IgE/ml and 4.8 +/- 3.2% using 0.1 microgram anti-IgE/ml (p less than 0.002, Wilcoxon's signed rank test), and averaged 3.0 +/- 4.3 and 3.1 +/- 5.3%, respectively, in control subjects (p greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

A shift from central and mixed sleep apnea to obstructive sleep apnea resulting from low-flow oxygen.

Low-flow oxygen decreases the frequency of the 3 types of apnea (central, mixed, and obstructive) in patients with predominantly obstructive sleep apnea. The decrease in frequency appears to be accompanied by a shift in apnea distribution, consisting of a decrease in the proportion of central and mixed apneas and an increase in that of obstructive apneas. To determine whether this shift represents a greater inhibitory effect on central and mixed apneas or an increased tendency toward obstructive apneas, we administered low-flow oxygen during sleep to 9 patients who demonstrated predominantly central and mixed sleep apnea (51 +/- 33% and 33 +/- 21% of apneic events, respectively, mean +/- SD) and had resting, room air, oxygen tensions of 83 +/- 11 mmHg. During non-REM sleep, oxygen increased the baseline oxyhemoglobin saturation while reducing the average peak fall in oxyhemoglobin saturation during each apneic event. Oxygen reduced the overall apnea frequency from 66 +/- 7.8 (mean +/- SE) to 43.0 +/- 10.7 episodes per hour (p less than 0.02). Central and mixed apneas decreased markedly from 31.4 +/- 0.6 to 6.4 +/- 4.3 episodes per hour (p less than 0.02) and from 20.9 +/- 5.0 to 4.9 +/- 1.5 episodes per hour (p less than 0.02), respectively. However, obstructive apnea frequency more than doubled from 13.9 +/- 7.0 to 32.1 +/- 9.2 episodes per hour (p less than 0.02). We conclude that in these patients oxygen tension altered both the frequency and distribution of sleep-induced apnea, with a lower oxygen tension increasing the frequency of central and mixed apneas and a higher oxygen tension increasing the frequency of obstructive apneas.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1985

Cryptogenic hemoptysis. Clinical features, bronchoscopic findings, and natural history in 67 patients.

We reviewed the clinical outcome of 67 patients with hemoptysis and a normal or nonlocalizing chest roentgenogram and nondiagnostic fiberoptic bronchoscopic examination. During a 38 +/- 22 (SD) month period after bronchoscopy, 57 (85%) patients remained well without evidence of active tuberculosis or overlooked bronchogenic carcinoma, and 9 patients died of nonpulmonary conditions. One patient developed bronchogenic carcinoma 20 months after bronchoscopy and resolution of symptoms. Hemoptysis had resolved completely before hospital discharge in 38 (57%) patients, within 6 months in 60 (90%), and recurred in only 3. Five patients (7.5%) had intermittent episodes of bleeding for more than 1 year. Fiberoptic bronchoscopy effectively excludes specific underlying causes of hemoptysis in the setting of a normal chest roentgenogram. The prognosis for patients with cryptogenic hemoptysis is generally good, usually with resolution of bleeding within 6 months of evaluation.

Adult↗
PubMed1985

Weight loss in mildly to moderately obese patients with obstructive sleep apnea.

The therapeutic effects of weight loss were evaluated in 15 hypersomnolent patients with moderately severe obstructive sleep apnea. As patients decreased their body weight from 106.2 +/- 7.3 kg (mean +/- SE) to 96.6 +/- 5.9 kg, apnea frequency fell from 55.0 +/- 7.5 to 29.2 +/- 7.1 episodes/h (p less than 0.01) in non-rapid-eye-movement sleep with an associated significant decline in the mean oxyhemoglobin saturation during the remaining episodes of sleep apnea from 11.9 +/- 2.4% to 7.9 +/- 1.9% (p less than 0.02). Sleep patterns also improved, with a reduction in stage I sleep from 40.2 +/- 7.3% to 23.5 +/- 4.8% (p less than 0.01), and a rise in stage II sleep from 37.3 +/- 7.0% to 49.4 +/- 4.6% (p less than 0.03). In the 9 patients with the most marked fall in apnea frequency, the tendency toward daytime hypersomnolence was decreased (p less than 0.05). No significant changes in sleep patterns occurred in 8 age- and weight-matched control patients who did not lose weight. Moderate weight loss alone can alleviate sleep apnea, improve sleep architecture, and decrease daytime hypersomnolence.

Body Weight↗
PubMed1984

Evaluation of sleep-disordered breathing. Is polysomnography necessary?

To determine whether polysomnography is necessary to assess the presence and severity of sleep-disordered breathing, bedside observations by physicians were compared with the results of polysomnography in 37 patients with clinically suspected obstructive sleep apnea. Physician observations correlated with objective findings from polysomnography in detecting the presence of obstructive apnea (p less than 0.01), and had a high specificity and positive predictive value. The 20 patients correctly identified by clinical observation had a longer duration of apneic episodes (p = 0.02), increased severity of snoring (p = 0.02), resuscitative snoring (p less than 0.02), and paradoxic thoracoabdominal movement (p less than 0.05). However, 11 other patients with sleep-disordered breathing were not identified clinically; therefore, the sensitivity (64.5 percent) and diagnostic accuracy (70.3 percent) of brief clinical observation were low. Furthermore, the physicians' determinations of the severity of the condition on the basis of bedside estimates of disordered breathing rate, duration of episodes, and the degree of associated hemoglobin oxygen desaturation did not correlate with objective measurements. These findings suggest that a single, brief clinical observation alone is an ineffective screening procedure for detecting obstructive sleep apnea.

Adult↗
PubMed1984

Effect of alpha-adrenergic blockade on exercise-induced asthma and conditioned cold air.

Cooling and drying of the intrapulmonary airways have been shown to be important stimuli for the development of bronchospasm induced by exercise and isocapnic cold air hyperventilation. It has also been suggested that alpha-adrenergic receptor activity is increased at lower temperatures. To evaluate the role of alpha-adrenergic activity in the development of bronchoconstriction during airway cooling, we examined the effects of alpha-adrenergic blockade with phentolamine on bronchospasm induced by exercise and isocapnic cold air hyperventilation in 8 asthmatics. Exercise consisted of 6 min of steady-state exercise at 90% predicted maximal heart rate breathing compressed air at 0% humidity and 21 +/- 1 degrees C (mean +/- SD). During baseline exercise studies, FEV1 fell 41.6 +/- 15.8%, but only 12.8 +/- 8.5% during alpha-adrenergic blockade (p less than 0.001). Isocapnic cold air challenge consisted of breathing compressed cold air (0% humidity, -17 +/- 4 degrees C) for 3-min periods, with stepwise increases in minute ventilation (Ve) until the FEV1 fell at least 20%. During baseline cold air challenges, FEV1 fell 20% (PD20 FEV1) at a Ve of 48.8 +/- 21 L/min. However, during alpha-adrenergic blockade 6 asthmatics were able to achieve much higher levels of VE (86.6 +/- 22.7 L/min) before FEV1 fell 20% (p less than 0.01), and 2 asthmatics did not decrease their FEV1 by 20%, despite reaching maximal levels of ventilation of 132 and 108 L/min, respectively. Alpha-adrenergic blockade did not affect airways responses to histamine or ragweed antigen (p greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1984

The effects of oxygen in patients with sleep apnea.

The effects of 6 h of continuous low flow, nasally administered oxygen were compared with the effects of breathing air in 10 men and 2 women with obstructive sleep apnea and daytime hypersomnolence. The overall quality of sleep, sleep fragmentation, the pattern of breathing, nocturnal oxygenation, and the clinical effects on daytime hypersomnolence determined by multiple sleep latency testing were evaluated. We found that in non-REM sleep, breathing 3 L/min of oxygen increased baseline percent arterial oxyhemoglobin saturation and decreased both the rate of sleep-disordered breathing from 69 +/- 36 to 56 +/- 39 (mean +/- SD) (p less than 0.02) episodes per hour and the peak fall in arterial oxyhemoglobin saturation from 11.5 +/- 5.6% to 6.5 +/- 4.0% (p less than 0.001). In addition, oxygen significantly reduced the percentage of central and mixed sleep-disordered breathing events, thus increasing the percentage of obstructive sleep-disordered breathing events. In contrast, during REM sleep, neither the baseline nor the peak fall in oxyhemoglobin saturation during disordered breathing improved; however, there was a significant reduction in hourly sleep-disordered breeathing rate from 70 +/- 17 to 56 +/- 23 (p less than 0.02) episodes. These improvements in oxygenation and pattern of breathing were associated with improved sleep architecture characterized by a decrease in the number of awakenings from sleep and an increased total sleep time from 335 +/- 72 to 369 +/- 68 min (p less than 0.05). Although 7 of 12 patients felt more alert after oxygen therapy, there was no overall improvement in multiple sleep latency test results.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1984

Radionuclide localization of massive pulmonary hemorrhage.

Lung scans with technetium sulfur colloid were performed in ten patients with life-threatening hemoptysis and nondiagnostic chest roentgenograms. Localized deposition of radionuclide was demonstrated in five of the six patients who were studied during active bleeding. These abnormalities were confirmed bronchoscopically in four patients, and lung scans provided clinically useful information regarding the bleeding site that had not been available from the medical history, physical examination, or chest roentgenogram. Evaluation with radionuclide scanning may complement bronchoscopic and roentgenographic studies in selected patients with massive pulmonary hemorrhage.

Adult↗
PubMed1984

Upper airway function in burn patients. Correlation of flow-volume curves and nasopharyngoscopy.

To determine whether upper airway dysfunction is detectable in patients with thermal injury, flow-volume curves were performed in 42 burn patients who were at risk for acute upper airway obstruction. Eighteen (42.9%) patients had abnormal inspiratory curves that were consistent with variable extrathoracic obstruction, a finding in only 8 (16%) of 50 nonburn control patients (p less than 0.01). A sawtooth pattern of the expiratory flow-volume curve was observed in 12 (28.6%) burn patients and in 5 (10%) control patients (p less than 0.05). The presence of diminished peak and midinspiratory flow rates (p less than 0.05) and patterns of extrathoracic obstruction (p less than 0.01) in burn patients correlated with the severity of anatomic injury visualized during fiberoptic nasopharyngoscopy and was more sensitive than the history and physical examination in detecting upper airway injury. Furthermore, flow-volume curve abnormalities were correlated (p less than 0.05) with the eventual need for endotracheal intubation. We conclude that physiologic dysfunction is often detectable using flow-volume curves in such burn patients, correlates with structural changes observed during nasopharyngoscopy, and is useful in the early assessment of patients at risk for upper airway obstruction.

Adult↗
PubMed1984

Exercise-induced asthma. Physiologic and clinical considerations.

This article discusses the physiologic and clinical aspects of exercise-induced asthma. Alterations in heat and water exchange in the respiratory tract appear to be important in initiating exercise-induced asthma, which can be reproduced by isocapneic hyperventilation with cold dry air. These pulmonary responses are also closely related to the level of non-specific airways hyperreactivity. Proposed mechanisms by which airways cooling and drying produce bronchospasm are reviewed and therapeutic approaches are discussed.

Anaphylaxis↗
PubMed1983

Effects of blood transfusion on exercise capacity in patients with sickle-cell anemia.

Although sickle cells have increased intracellular viscosity, the viscosity of patient's blood is usually not increased, because of the low hematocrit typically found in such patients. When patients receive transfusions, their exercise capacity increases, but it is unclear whether the change is due primarily to increased hemoglobin concentration, or also reflects improved flow properties of the blood due to dilution of sickle cells with normal erythrocytes. To evaluate the relative importance of these two factors, submaximal exercise studies were performed before and after a series of transfusions. Exercise capacity improved and the patients were able to perform increased amounts of work at lower heart rates. Regression analyses indicated that the percent of sickle cells in patient's blood did not have a significant effect on exercise capacity after the transfusion-induced increase in hemoglobin concentration was taken into account. At the hematocrits typically found in patients, altered viscosity of blood due to the presence of sickle cells is much less important than hemoglobin concentration as a determinant of exercise capacity.

Adolescent↗
PubMed1983

Flow-volume curves and sleep-disordered breathing: therapeutic implications.

To assess the relationship of abnormal flow-volume curves during awake periods to the clinical severity of sleep-disordered breathing and the need for surgical treatment of obstructive sleep apnoea, flow-volume curves were measured in 72 adults with obstructive apnoea. Patients in whom surgery was recommended for standard clinical indications had significantly lower inspiratory flow rates (p less than 0.01) and a higher incidence of flow-volume curves indicating extrathoracic airway obstruction (p less than 0.01) than did non-surgical patients. These abnormal flow-volume curves correlated with an increased severity of nocturnal oxygen desaturation (p less than 0.01). Furthermore, increases in inspiratory flow rates measured serially in 22 patients were related to improvement in their polysomnography (p less than 0.05), suggesting that alterations of airway function during awake periods correlate with changes in the severity of sleep apnoea.

Female↗
PubMed1983

The effects of protriptyline in sleep-disordered breathing.

The effects of therapy with the tricyclic antidepressant protriptyline were studied in 12 patients with hypersomnolence and moderately severe sleep apnea. After treatment there was no significant change in the duration or frequency of sleep-disordered breathing (SDB) during non-REM sleep, but there was an alteration in the breathing pattern characterized by a decrease in the amount of apnea during SDB events. Apnea, as a percent of disordered breathing time, fell from 60.4 +/- 27.2% to 35.5 +/- 26.7% (p less than 0.01) and was accompanied by a reduction in the peak fall in oxygen saturation from 16.2 +/- 6.2% to 9.2 +/- 4.7% (p less than 0.01). During REM sleep there was no change in the pattern, duration, or frequency of SDB, or reduction in the peak fall in oxygen saturation. However, there was a reduction in the amount of Stage REM sleep, thereby reducing the more severe SDB events (p less than 0.01) and further improving nocturnal oxygenation. In 10 of 12 patients, there was subjective improvement in daytime hypersomnolence, which was associated with an increase in median sleep onset time from 3.3 +/- 2.2 to 5.1 +/- 2.1 min (p less than 0.01). Although all patients developed mild side effects from the anticholinergic properties of protriptyline manifested by a dry mouth, 4 patients noted additional side effects including urinary hesitancy, mild constipation, and difficulty in maintaining an erection. One patient developed intolerable constipation that necessitated discontinuation of the drug. We conclude that protriptyline reduced daytime hypersomnolence and altered the pattern of SDB, thus improving gas exchange and oxygenation during sleep. Therefore, in selected patients with moderately severe obstructive sleep apnea, therapy with protriptyline is an alternative to surgical treatment with a tracheostomy.

Adult↗