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T J Witek

Publications and source records attributed to T J Witek.

63 records · Page 4Linked to original sources
PubMed1983

Air pollution and respiratory health.

Air pollution is frequently incriminated as a risk factor in the development of chronic lung impairment and in the aggravation of existing disease. The federal government has set primary air quality standards to protect public health and secondary standards to protect public welfare (eg, to preserve vegetation and buildings). Much of the debate surrounding the development and evaluation of air standards focuses on the diseases of patients with whom the respiratory care practitioner has daily contact. We review the legislative efforts to protect the public from the effects of air pollution and provide insight into some of the scientific and medical dilemmas involved in this current public health issue.

Air Pollution↗
PubMed1983

A review of the hospital course of asthmatic children and adults.

We reviewed 82 consecutive hospital admitted patients treated for acute severe asthma over a seven-month period at a University medical center and an additional 25 patients at an affiliated community hospital. Those asthmatics treated on the adult medical service had a significantly longer length of hospitalization when compared to those treated on the pediatric service (t = 5.12; p less than 0.005). In addition, longer hospitalization periods were noted for those asthmatics who smoked (t = 2.98; p less than 0.005) and for those with a history of chronic bronchitis (t = 2.32; p less than 0.025). Drug regimens were frequently suboptimal; 30% of the patients reviewed were receiving no therapeutic agents prior to admission. Of those patients receiving theophylline 53% had serum levels of less than 10 mcg/ml on their post admission assessment. Although frequently suboptimal, inadequate drug regimens prior to admission did not lengthen hospital stay. Poor compliance with medications was recorded as a major cause of decompensation in nine patients whose mean age was 13 years. Finally, occupational exposure to airway irritants was elicited from 24% of the adult population at the University medical center. Increased length of stay in the hospital for adult asthmatics may reflect relatively fixed airway disease among these patients since a significant proportion of them related a history compatible with chronic bronchitis or were smokers. Occupational histories should be evaluated in adult asthmatics to rule out workplace exposures as a cause for severe decompensation. In addition, the importance of educational efforts addressing therapeutic non-compliance is evident from this study.

Adolescent↗
PubMed1982

Epidemiology and epidemiologic methods: an introduction for respiratory care practitioners.

Epidemiology is the study of the distribution of disease in a population and of the factors that determine that distribution. Respiratory care practitioners encounter many aspects of epidemiology in training and practice and should become aware that most initial epidemiologic observations are made by clinicians. The determinations that excessive oxygen administration caused retrolental fibroplasia and that exposure to cotton bracts in the textile industry caused byssinosis resulted from the collaborative efforts of epidemiologists, laboratory workers, and clinicians. The three types of study designs in observational epidemiology are: (1) the cohort (incidence) study, in which a study factor is observed at the onset of the study and the study population is followed over time for the development of new cases of a disease; (2) the cross-sectional (prevalence) study, in which the presence or absence of risk factors is measured at one point in time in a study population and prevalence rates of disease among those with and without the risk factors are compared; and (3) the case-control study, in which the numbers of persons with and without a given disease who share certain background characteristics or exposure levels to risk factors are determined and compared. The epidemiologist's continued collaboration with the clinician and the laboratory scientist is important because epidemiology alone can rarely provide conclusive solutions to every aspect of a problem.

Epidemiologic Methods↗
PubMedDate not supplied

Airway effects of low concentrations of sulfur dioxide: dose-response characteristics.

The acute respiratory effects of exposure to low-level, short-term sulfur dioxide (SO2) were studied in ten asthmatic and ten healthy subjects. Subjects were exposed in an environmental chamber in a double-blind, random sequence to SO2) levels of 0.00, 0.25, 0.50, 0.75, and 1.00 ppm for 40 min. During the first 10 min subjects exercised on a cycloergometer at a level of 450 kpm/min. On separate days, subjects were exposed to 0 and 1.0 ppm SO2 in the absence of exercise. In exercising asthmatic subjects, breathing 1 ppm SO2 resulted in significant changes from baseline in airway resistance (Raw), forced expiratory volume in 1 sec (FEV1.0), maximal expiratory flow at 60% of the vital capacity (VC) below total lung capacity on the partial flow volume curve [MEF40% (P)] as well as reductions in flows at 50% of VC (Vmax50%). None of these parameters showed significant changes for exposures to 0.5 ppm or less, with the exception of small decreases (i.e., less than 0.2 L/sec) in Vmax50% at 0.25 and 0.5 ppm. Ten minutes after the end of exercise, there were no statistically significant differences from baseline, even though SO2 was still present in the chamber atmosphere. For asthmatic subjects, the average changes in Raw, FEV1.0, MEF40%(P), and Vmax50% increased as SO2 levels increased, suggestive of a dose-response relationship with a consistent effect first seen at 0.75 ppm. In individual exercising asthmatics, responses may occur at levels of SO2 below 0.75 ppm. No changes were seen in healthy individuals on any day, or in asthmatic subjects at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMedDate not supplied

A study of respiratory effects from exposure to 2 ppm formaldehyde in healthy subjects.

Formaldehyde (FA) is a common indoor air pollutant with irritative properties. It has been suggested that FA may produce physiologic alterations of the respiratory system. To study such responses, 15 nonsmoking, healthy subjects were exposed in a double blind, random manner to 0 and 2 ppm FA for 40 min in an environmental chamber. In addition, the same exposures were repeated on a separate day with the subjects performing moderate exercise (450 kpm/min) for 10 min. Exposures were carried out under controlled environmental conditions (temperature = 23 degrees C, relative humidity = 50%). Pulmonary function was measured before, during, and after exposures using partial and maximal flow-volume curves and airway resistance. Symptom diaries were given to the subjects; upper and lower airway symptoms were recorded for up to 24 hr following exposures. No significant bronchoconstriction was noted in this group. In 3 subjects, sequential measurements of peak flow over a 24-hr period following FA exposure failed to reveal any delayed airway response. On a separate day, 6 healthy subjects failed to demonstrate changes from their baseline responsiveness to methacholine after exposure to 2 ppm FA. Respiratory symptoms were, in general, confined to the upper airways and were mild to moderate in severity. We conclude that short exposures to 2 ppm FA do not result in acute or subacute changes in lung function among healthy individuals either at rest or with exercise. Subjective complaints following such exposures are confined to irritative phenomena of the upper airways.

Adult↗
PubMedDate not supplied

Respiratory findings in spice factory workers.

The respiratory consequences of working in the spice industry were studied in 92 female spice factory workers (mean age, 36 yr; mean exposure, 12 yr). A control group of 104 female workers employed in a nondusty industry was also studied. The prevalence of chronic respiratory symptoms was significantly higher in the exposed than in the control group. In particular, the prevalence of dyspnea (57.6%), chronic cough (22.8%), chronic phlegm and chronic bronchitis (19.6%), nasal catarrh (37.0%), and sinusitis (22.2%) was high when compared to controls (p less than .01). Among spice factory workers, a high prevalence of acute symptoms during the workshift was recorded. Acute reductions in lung function were statistically significant over the workshift for forced vital capacity (FVC), -2.0%; forced expiratory volume in one second (FEV1.0), -3.0%; and for maximum expiratory flow rates at 50% (FEF50), -8.3% and at 25% (FEF25), -15.2% measured on maximum expiratory flow-volume (MEFV) curves. No difference was found in across-shift ventilatory function in workers with or without chronic respiratory symptoms, except for FEF25 (with symptoms, 16.7%; without symptoms, 9.6%). Preshift administration of 40 mg of disodium cromoglycate (DSC) inhaled 15 min before the workshift significantly diminished acute reductions in FEF50 and FEF25 in exposed workers. Monday preshift FEF50 and FEF25 in exposed workers were significantly lower than in control workers (p less than .01), which suggests an early irreversible component to this illness.

Adolescent↗
PubMedDate not supplied

An evaluation of nasal response following different treatment regimes of oxymetazoline with reference to rebound congestion.

This was a randomized, double-blind vehicle controlled study aimed at investigating the effects on nasal function of 7 days treatment with the topical decongestant oxymetazoline (0.05% w/v). Fifty healthy volunteers took part in the study and these were randomly allocated to three treatment groups (i) daily oxymetazoline (b.i.d. 150 microliters per nostril) (ii) intermittent oxymetazoline, with oxymetazoline being substituted for vehicle at the morning doses on days 1, 3, and 7; and (iii) daily vehicle (b.i.d. 150 microliters per nostril). The nasal airway was assessed by measurement of nasal airway resistance (NAR) using posterior rhinomanometry, subjective scaling of nasal patency by means of a visual analogue scale (VAS), and clinical visual examination. On days 1, 2, 3, and 7, NAR and VAS measurements were obtained before the morning dose and up to 6 hours after dosing; clinical visual examinations were also performed before dosing on these days. NAR and VAS measurements were also made following withdrawal of treatment on Days 8 and 9. Nonparametric analysis of the results showed that therapeutic tolerance to oxymetazoline did not develop over the 7-day treatment period, and visual examination of the nasal mucosa failed to find significant evidence of rhinitis. Evidence of rebound nasal congestion was found following 3 days of oxymetazoline treatment, with baseline NAR within the daily and intermittent oxymetazoline groups being significantly greater on Day 3 compared to Day 1 (p < 0.05). However, there was a trend toward increasing baseline NAR in the vehicle group over the course of the study, suggesting that the vehicle may have contributed to the rebound congestion. Following the withdrawal of treatments, only the intermittent oxymetazoline group had significantly higher NAR on Days 8 and 9 compared to Day 1 (p < 0.05). Subjective VAS measurements generally followed trends in NAR.

Adolescent↗
PubMedDate not supplied

An evaluation of respiratory effects following exposure to 2.0 ppm formaldehyde in asthmatics: lung function, symptoms, and airway reactivity.

Fifteen asthmatic volunteers were exposed in a double-blind, random manner to room air and 2.0 ppm formaldehyde for 40 min in an environmental chamber. These exposures were repeated on a separate day during moderate exercise (450 kpm/min) for 10 min. Ambient and dew point temperatures were 23.0 +/- 0.0 degrees C and 11.5 +/- 1.0 degrees C, respectively. No significant airway obstruction as measured by flow-volume parameters and airway resistance was noted in this group during or immediately after exposure. Furthermore, sequential measurements of peak flow for 24 hr following formaldehyde exposure revealed no delayed airway response. In contrast, in comparison to the baseline methacholine inhalation challenge (MIC) test on the screening day, 8 of 12 asthmatics demonstrated a lower threshold to MIC following 2.0 ppm exposure for 40 min; however, the mean and median decrements of threshold in methacholine concentration of 10.4 mg/ml and 24.3 mg/ml were not significant (p = .12). Bad odor, sore throat, and eye irritation were common during exposure but symptoms were infrequent afterward.

Adult↗