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Biomedical subjects

L J Brooks

Publications and source records attributed to L J Brooks.

32 records · Page 2Linked to original sources
PubMed1991

Behavioral assessment and management of food refusal in children with cystic fibrosis.

Four children with cystic fibrosis, ranging in age from 10 to 40 months, were admitted to a specialized pediatric unit for evaluation and treatment of malnutrition. All were below the fifth percentile for weight despite appropriate pancreatic enzyme replacement and outpatient nutritional counseling. Dietary evaluation revealed oral intake of 48% to 62% of that required for growth. Standardized nursing and psychological assessments of feeding behaviors during meals indicated a low acceptance rate of foods and a high rate of maladaptive feeding behaviors. Treatment consisted of behavioral management using positive reinforcement of food acceptance, extinction of negative behaviors, and parent training. Mean percentage of caloric intake increased from 54% to 92% for the four patients. At long-term follow-up, the patients who continued the program demonstrated substantial and persistent catch-up growth. Behavioral feeding disorders may contribute to failure to thrive in patients with cystic fibrosis and must be considered when growth failure occurs despite correct medical management and apparently mild pulmonary and gastrointestinal involvement.

Behavior Therapy↗
PubMed1990

Tracheal size and distensibility in patients with cystic fibrosis.

Retrospective studies have reported that tracheal enlargement is common in patients with cystic fibrosis (CF). To determine whether significant tracheal enlargement occurs in these patients, we used the acoustic reflection technique to prospectively measure the tracheal cross-sectional area near functional residual capacity (FRC) in 39 stable outpatients with CF and 39 age- and sex-matched normal control subjects. The patients with CF had a mean age of 19.0 yr with a mean percent predicted FEV1 of 69%. The mean +/- SEM tracheal area of the patients with CF was 1.99 +/- 0.13 cm2, compared with a mean tracheal area of 1.87 +/- 0.10 cm2 in the control subjects (t = 0.79, NS). CF tracheal area was not a function of age nor of disease severity, as assessed by percent predicted FEV1. To determine whether tracheomegaly might occur only in older patients, we examined the six patients with CF who were 28 yr of age or older. Mean tracheal area for these older patients with CF was 2.46 +/- 0.26 cm2, compared with 2.27 +/- 0.10 cm2 for the control subjects (t = 0.70, NS). Eleven patients with CF also had their tracheal area measured near TLC. At this high lung volume, the tracheal area of the patients with CF was 2.62 +/- 0.23 cm2, significantly larger than the 1.91 +/- 0.13 cm2 in 11 control subjects (t = 2.68, p less than 0.02). The increase in tracheal area per change in lung volume was also significantly greater in the patients with CF than in the control subjects (t = 3.33, p less than 0.01). We conclude that near FRC the tracheal size of patients with CF is not different from that of age- and sex-matched control subjects. The tracheas of patients with CF expand more than do the tracheas of control subjects when higher lung volumes are attained, suggesting increased airway distensibility.

Adolescent↗
PubMed1989

A prospective randomized double-blind study to evaluate the effect of dexamethasone in acute laryngotracheitis.

To determine whether a single dose of dexamethasone (0.6 mg/kg) is useful in the treatment of acute laryngotracheitis (croup), 29 hospitalized patients with acute laryngotracheitis were randomly assigned in a double-blind fashion to receive either parenterally administered dexamethasone (n = 16) or a saline placebo (n = 13). Severity of the illness was assessed by a clinical croup score based on retractions, stridor, air entry, cyanosis, and level of consciousness. Twelve hours from the time of injection, the patients receiving the dexamethasone had a statistically significant decline in median croup score from 4.5 to 1.0 (p less than 0.001), whereas the patients receiving the placebo did not. By 24 hours, a decline of two or more points in the total croup score was noted in 85% of the patients in the dexamethasone group compared with 33% of the patients in the placebo group (p = 0.027). During this same period, only 19% of patients receiving dexamethasone required two or more racemic epinephrine treatments in comparison with 62% of patients who received the placebo (p less than 0.05). There was no statistical difference between the two groups in improvement in oxygen saturation, respiratory rates, or duration of hospitalization. We conclude that dexamethasone is beneficial in reducing the overall severity of moderate to severe acute laryngotracheitis during the first 24 hours after injection.

Acute Disease↗
PubMed1989

Reproducibility of measurements of upper airway area by acoustic reflection.

To evaluate the extent and nature of the variability of measurements of upper airway area by acoustic reflection (AAAR), we made repeated measures of pharyngeal AAAR in 10 normal adult volunteers. We selected mean pharyngeal area as a better index of upper airway size than peak pharyngeal area or pharyngeal volume. Within-run variability of this measure was 8 +/- 4% (SD) (coeff of variation). This variability could not be explained by changes in lung volume or differences in phase of respiration. Five subjects had tracheal and pharyngeal area measured by using both the custom-made wax mouthpiece (W) and a commercial rubber pulmonary function mouthpiece (R). Reproducibility of pharyngeal AAAR was within 10% (coeff of variation) using R, but measurements of pharyngeal AAAR varied with the different types of mouthpiece, as W/R ranged from 0.72 to 1.70. In contrast, measurements of midtracheal area were similar for both mouthpiece types [mean W/R = 0.97 +/- 14 (SD)]. The acoustic reflection technique yields a reproducible index of pharyngeal size that does not vary with phase of respiration or modest changes in lung volume. Either W or R may be used to make clinical measurements, but the type of mouthpiece should be consistent and specified.

Acoustics↗
PubMed1988

Relationship between lung volume and tracheal area as assessed by acoustic reflection.

To determine whether airway size correlates with measures of lung or body size, we used the acoustic reflection technique to calculate tracheal cross-sectional area in 103 healthy young adults. Men have significantly larger tracheas than women [2.48 +/- 0.08 vs. 1.91 +/- 0.05 (SE) cm2, P less than 0.001]. Within each sex, there is no correlation between tracheal size and body size or maximal expiratory flows. There is a significant positive correlation between tracheal area and vital capacity in males only (r = 0.36, P less than 0.01). These results support the concept of dysanapsis, relatively independent growth of the airways and lung parenchyma, as well as sex-related differences in airway size and growth. Inherent airway size may be a factor in the development and/or progression of lung disease.

Acoustic Impedance Tests↗
PubMed1984

Reproducibility and accuracy of airway area by acoustic reflection.

To determine the accuracy and reproducibility of measurements of airway area by acoustic reflection (AAAR) we made repeated measurements of tracheal areas in human volunteers, glass airway models, and excised canine tracheae. In 10 adult males, the mean ratio of tracheal AAAR to tracheal areas determined roentgenographically was not significantly different from one (1.06 +/- 0.13 SD). Within-run variability was 10 +/- 4% (CV), mean intrasubject day-to-day variability was 9 +/- 4% (CV). A custom-made mouthpiece is necessary for accurate measurements of AAAR. Mean variability related to differences in mouthpiece construction was 7 +/- 6% (CV). The effect of variations in upper airway and glottic sizes on tracheal AAAR measurements was investigated using glass airway models. In model studies, tracheal AAAR measurements were found to be independent of changes in proximal airway size for glottic apertures greater than or equal to 1 cm2 and upper airway areas less than or equal to 8 cm2. Tracheal area was, however, overestimated by 20% in the rigid-walled glass models. The effects of airway wall rigidity were qualitatively investigated by comparing acoustic and roentgenographic measurements of excised canine tracheae surrounded by either air or petroleum jelly. Differences in the accuracy of measurements of AAAR in vitro and in vivo are probably due to differences in airway wall inertance. These studies suggest that the measurement of AAAR yields an accurate and reproducible result that may be clinically useful for the noninvasive detection of changes in central airway geometry.

Acoustics↗
PubMed1982

Significance of roentgenographic abnormalities in children hospitalized for asthma.

The relatively high incidence of roentgenographic abnormalities in patients hospitalized for acute asthma has led some to recommend that all such patients receive chest x-ray examination upon admission to the hospital. We studied the incidence and clinical predictability of the roentgenographic findings by asking the admitting physician to indicate, prior to obtaining a roentgenogram, whether he thought pneumonia, pneumothorax, pneumomediastinum or other significant abnormality was present. A treatment plan was also outlined at that time. Seven of 128 patients (5.5 percent) had roentgenograms suggestive of pneumonia or pneumothorax; three of these were suspected clinically. In 14 cases the clinical suspicion of pneumonia or pneumothorax was not borne out roentgenographically. The initial treatment plan was altered in only three cases. The low incidence of roentgenographic abnormalities and the failure of these minor abnormalities to substantially influence treatment suggest that routine chest roentgenograms may not have to be performed on all children hospitalized for acute asthma.

Adolescent↗
PubMed1981

Theophylline therapy in bronchiolitis. A retrospective study.

Since bronchiolitis has clinical and pathophysiologic similarities to asthma, the use of bronchodilator drugs has been suggested; however, their effectiveness remains unproven. We reviewed the outcome of treatment in 64 children less than 18 months of age hospitalized for the first time with a diagnosis of bronchiolitis or wheezing. Thirty one of the patients received theophylline therapy and sometimes steroids and/or inhaled sympathomimetic drugs, and 34 received no such therapy. Although the theophylline-treated children were older (9.4 vs 4.9 months of age), there were no other differences in the histories, clinical findings, laboratory assessments, or outcome between theophylline-treated and untreated groups. The results suggest that theophylline and steroid therapies had not beneficial effects on the resolution of acute bronchiolitis or wheezing in the majority of infants and small children.

Adrenal Cortex Hormones↗