Biomedical subjects
Publications and source records attributed to M Kattan.
A case of hyperlucent lung, the Swyer-James syndrome, diagnosed by computed tomography (CT) scan is presented. The CT findings and the role of this modality in establishing the diagnosis are discussed.
We retrospectively reviewed the time course of recovery of pediatric patients in status asthmaticus who were undergoing mechanical ventilation for life-threatening respiratory failure to evaluate the results with current medications and technology. Ten patients between 2 and 18 years of age underwent intubation on 20 occasions. Mechanical ventilation was maintained for a mean of 2 days. Positive end-expiratory pressure was introduced in the recovery phase to prevent hypoxemia. Twelve episodes (Group 1) involved intubation less than 48 hours; in eight episodes (group 2) the patients required ventilatory support greater than 48 hours. The two groups did not differ in regard to age, pharmacologic therapy, preintubation arterial blood gas data, or initial ventilator settings, but the rise in pH and fall in Paco2 differed significantly over the first 12 hours of therapy. In the group 2 patients, peak pressures were not increased greater than 60 cm H2O despite elevated Paco2 values, and aggressive sodium bicarbonate therapy for pH correction was not pursued. Complications were few and all patients survived. We conclude that asthma patients have variable resolution of airway obstruction during mechanical ventilation and that controlled hypoventilation can be a safe therapy for the patients with more severe obstruction.
To quantitatively follow the progressive capillarization of the fetal airway epithelium, we examined human lung tissue from nine fetuses ranging in gestational age from 18-26 wk. Our goals were to 1) determine the initial time of appearance of the air blood barrier (ABB) in the fetus; 2) follow the increase in the number of ABB per total epithelial airway surface (capillary load) with gestational age; and 3) measure the thickness of the ABB. Our results, obtained by using light and electron microscopy and an interactive computerized morphometry system, show that ABB first appear at 19 wk. Increasing gestation is accompanied by an exponential increase in the number of ABB (r = 0.96) and the total surface area that the ABB contribute to the total surface area of airway epithelium (r = 0.93). ABB thickness is comparable to the dimensions of minimal barrier thickness of the adult ABB. The structural development that we describe may be one of the factors determining preterm viability.
A full-term infant developed bilateral pneumothoraces and respiratory distress shortly after birth, despite initially good Apgar scores. Persistent tachypnea, hypoxemia, and a chest X-ray remarkable for diffuse alveolar and interstitial infiltrates prompted a lung biopsy at 4 months of age. The biopsy revealed desquamative interstitial pneumonitis with the unique demonstration by electron microscopy of numerous alveolar brush cells. Respiratory brush cells occur normally in the trachea and bronchi of humans and mammals. Although identical cells have been noted in the alveoli of rats, they have never been reported in the alveoli of humans. We present the first electron microscopical demonstration of the alveolar brush cell in humans.
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A 15-yr-old male hemophiliac developed the acquired immune deficiency syndrome (AIDS). His terminal illness was characterized by rapidly progressive respiratory failure with intermittent wheezing, nonresponsive to bronchodilator and steroid therapy. Postmortem examination revealed a pseudomembrane covering the mucosa of the lower trachea and bronchi of both lungs. This pseudomembrane was composed predominantly of fungal hyphae speciated as Aspergillus niger. There was widespread transmural necrotizing bronchitis and fungal invasion that extended to involve a narrow zone of peribronchial tissues. The intervening lung parenchyma was free of fungal disease. This unique form of bronchitis is a distinct variant of invasive aspergillosis and merits recognition because of its clinical and prognostic implications.
We describe two adolescent patients in whom a disorder of the vocal cords associated with emotional factors resulted in acute episodes of stridor. Adduction of the vocal cords on inspiration and abduction on expiration was found on indirect laryngoscopy. The problem responded to either placebo treatment or psychotherapy. The similarity between vocal cord dysfunction presenting as stridor and that presenting as asthma is discussed. The importance of diagnosing these functional problems in children is emphasized in order to avoid unnecessary diagnostic procedures and hazardous treatment.
his report describes the ultrastructural alterations observed in the tracheal epithelium of a 13-year-old male with a history of recurrent pneumonia, chronic bronchitis, chronic otitis media, and situs inversus. The epithelium consisted of globlet and basal cells with many columnar cells that lacked cilia and basal bodies. The surface of these cells had regular microvilli and cytoplasmic features typical of brush cells.
We evaluated 4 treatment regimens using single and multiple injections of epinephrine for the initial treatment of acute asthma in children. Twenty-five patients received 2 injections of epinephrine followed by Sus-Phrine (Group EES) given 20 min apart, 25 received Sus-Phrine only (Group S), 24 received Sus-Phrine followed by 2 placebo injections 20 min apart (Group SPP), and 14 received epinephrine only (Group E). Clinical score and pulmonary function were assessed over a 2-h period. The failure rate was similar in Groups EES, S, and SPP (combined failure rate, 17.8%). The failure rate (46%) in Group E was significantly greater (p less than 0.05). The clinical score and pulmonary function was significantly better 5 min after the first injection in Group EES than in Groups S and SPP, but no significant differences were noted thereafter. At 25 min the pulmonary function was similar whether 1 or 2 epinephrine injections were administered. The number of patients exhibiting side effects was significantly greater in the groups receiving epinephrine than in the groups receiving Sus-Phrine only (p less than 0.05). The relapse rates during the 24-h period after the emergency room treatment were similar in Groups EES, S, and SPP (combined relapse rate, 14.3%). We conclude that repeated injections of epinephrine are necessary to sustain bronchodilation but that they do not have a cumulative effect. Furthermore, there is little therapeutic advantage of these repeated injections over a single injection of Sus-Phrine for the initial treatment of acute asthma.
The long-term consequences of acute lung injury during critical growth periods of the lung were evaluated by inducing mild bronchiolitis with nitrogen dioxide (NO2) in 3-day-old (newborn) and 21-day-old (young) hamsters. Hamsters were exposed to 30 ppm NO2 for 7 days. Age-matched animals exposed to room air served as controls. Lung volumes, static deflationary pressure-volume curves, mean linear intercept, and internal surface area were measured when the animals reached 1 yr of age. Newborns exposed to NO2 showed an increased volume at 25 cm H2O pressure (V25) adjusted for body weight, a decreased transpulmonary pressure at 60% of V25, and an increased mean linear intercept when compared with control animals. The internal surface area was less than that in the control animals; the difference approached significance. In the young exposed group there were no differences for any measurements when compared with the control group. These data indicate that a mild injury imposed during the newborn period may result in physiologic and morphometric changes that simulate mild emphysema in the mature animal.
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In two groups of patients, noncompliance with drug regimens resulted in misinterpretation of serum theophylline levels. All six chronic asthmatics in the first group, found in a retrospective review of 43 outpatient charts, had outpatient serum theophylline levels in the therapeutic range (10 to 20 microgram/mL) and at least a 7-microgram/mL greater inpatient theophylline level while receiving the same dosage. When hospitalized, four of these patients had serum theophylline levels in the toxic range (greater than 20 microgram/mL). In the second group four hospitalized patients had persistently low serum theophylline levels despite an adequate theophylline dose. When compliance was enforced, serum theophylline levels rose significantly. Compliance cannot be assumed in the outpatient with a serum theophylline level in the therapeutic range or in the hospitalized patient. Determination of serum theophylline level after supervised drug administration is recommended in inpatients requiring unusually high doses of theophylline or in those whose condition is poorly controlled despite having serum theophylline levels in the therapeutic range (10 to 20 microgram/mL).
Hypnosis has been used for many years in the treatment of asthma, but studies of its usefulness have been controversial. We assessed the efficacy of hypnosis in attenuating exercise-induced asthma (EIA) in 10 stable asthmatics. The subjects ran on a treadmill while mouth breathing for 6 min on 5 different days. Pulmonary mechanics were measured before and after each challenge. Two control exercise challenges resulted in a reproducible decrease in forced expiratory volume in one second (FEV1). On 2 other days, saline or cromolyn by nebulization was given in a double-blind manner with the suggestion that these agents would prevent EIA. Hypnosis prior to exercise resulted in a 15.9% decrease in FEV1 compared with a 31.8% decrease on the control days (p less than 0.001). Pretreatment with cromolyn resulted in a 7.6% decrease in FEV1. We conclude that hypnosis can alter the magnitude of a pathophysiologic process, namely, the bronchospasm after exercise in patients with asthma.
Two treatment regimens for the initial treatment of acute asthma in 50 patients between the ages of 12 and 20 years seen in the emergency room were evaluated. The treatments were randomized such that 26 patients received 2.5 mg of the beta 2-agonist fenoterol by nebulizer and 24 patients received 0.3 mg of epinephrine followed by 0.75 mg of Sus-Phrine. Clinical assessment and spirometry were performed over a two-hour period. Both groups responded within ten minutes and peak improvement was reached within one hour. Peak expiratory flow and clinical score were better following fenoterol treatment in the first hour (P less than .05). The one-second forced expiratory volume and the forced expiratory flow in the middle half of the vital capacity were greater at 20 minutes with fenoterol (P less than .05). Those with more severe obstruction (forced expiratory volume less than 30%) receiving aerosol therapy also had significantly greater improvement in the first 20 minutes compared with those who received injections. Four patients failed to respond to epinephrine whereas all patients showed improvement with fenoterol (P less than .05). These results demonstrated that an inhaled beta 2-agonist is effective in the initial treatment of acute asthma in children, regardless of severity, and avoids the need for injections.
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Nineteen children who were not steroid dependent and were hospitalized in status asthmaticus were studied to evaluate the effect of corticosteroids. They were randomized into two groups. Each group received salbutamol inhalations and intravenous aminophylline therapy. One group received 7 mg/kg hydrocortisone intravenously every six hours; the other group served as a control. Each group showed significant improvement in clinical score and peak expiratory flow rate after 36 hours; there was no statistical difference in the degree of improvement. Six of ten steroid-treated children and six of nine controls achieved a PEFR of 50% predicted by 36 hours. The response to inhaled salbutamol was similar in each group. The results show that in the first 36 hours of therapy, corticosteroids have no additive effect on the bronchodilator response of aminophylline and salbutamol and do not hasten the recovery of nonsteroid-dependent children in status asthmaticus. Although the results show that an inhaled sympathomimetic drug is beneficial in status asthmaticus, corticosteroid therapy does not increase the responsiveness of the airways to these agents.