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Biomedical subjects

J L Hankinson

Publications and source records attributed to J L Hankinson.

At least 19 recordsLinked to original sources
PubMed1991

Acceptability and reproducibility criteria of the American Thoracic Society as observed in a sample of the general population.

An analysis of spirograms of 6,486 subjects from the general population, ages 8 to 90, was conducted to determine their ability to satisfy the American Thoracic Society's (ATS) acceptability and reproducibility criteria. The results indicate that both older and younger subjects had more difficulty satisfying the ATS acceptability and reproducibility criteria. The difficulty in satisfying the ATS reproducibility criterion, particularly in younger subjects, was in part associated with their smaller heights and lung volumes. A relatively uniform within-subject variability of FVC and FEV1 in terms of the mean differences between the largest and second largest FVC and FEV1, for all heights, was observed. In addition, unlike the ATS reproducibility criterion, when a constant 200-ml reproducibility criterion for FVC and FEV1 was used, there was no longer a significant difference between the number of reproducibility criterion failures for the 14 different height groups used. These results suggest that the ATS reproducibility criterion, based on a percentage of the FVC and FEV1, may inappropriately classify a higher percentage of subjects with smaller heights and lung volumes as having a nonreproducible test. In contrast, subjects with larger heights and lung volumes are much less likely to fail the ATS reproducibility requirement. These results emphasize the importance of following the ATS recommendation of using the reproducibility criterion only as a goal during data collection, not to classify a subject as having an invalid test.

Adolescent↗
PubMed1991

Changes in forced expiratory volume in one second and peak expiratory flow rate across a work shift among unexposed blue collar workers.

Pre- and postshift spirometry was obtained on 1,113 blue collar workers employed at 35 work sites judged to have no hazardous occupational respiratory exposures on the basis of inspection visits and environmental sampling. In addition to spirometry, a standardized questionnaire was administered by trained personnel. A study population of 944 remained after exclusion of workers for incomplete demographic data and/or spirometry with poor within-session reproducibility, i.e., greater than or equal to 10% variability in the two largest values of either FVC and/or FEV1. Overall mean values of changes across the work shift in FEV1 and peak expiratory flow rate (PEFR) were -0.8% (-0.04 L) and +2.1% (+0.13 L/s), respectively. Standard deviations for these across-shift changes were 5.8% (0.19 L) and 13.2% (1.19 L/s) for FEV1 and PEFR, respectively. In univariate analyses, mean values of across-shift changes were not statistically related to age, race, sex, smoking status, work shift, or FEV1/FVC ratio. However, variability (i.e., standard deviation) of across-shift changes were significantly related to some of these factors. These observations provide a basis for interpreting results of occupational respiratory morbidity surveys involving measurement of changes in FEV1 and/or PEFR across a work shift.

Adolescent↗
PubMed1989

Workplace measurement of respirator effects using respiratory inductive plethysmography.

A useful system to study the cardiopulmonary effects of respirators in the workplace would be reliable, portable, and lightweight and would not encumber the nose or mouth or require modification to the respirator. Twenty men using such a system (which measured ventilatory parameters by respiratory inductive plethysmography [RIP]) were studied. The subjects all performed their usual jobs which involved some work with and some without a respirator. Twelve subjects used airline respirators and eight used air-purifying respirators. The RIP equipment measurements included respiratory frequency, tidal volume (VT), minute ventilation (V), and heart rate (HR). The RIP data from 20 other subjects was lost because of equipment malfunction, primarily lead separation in those whose jobs involved climbing around large workpieces. In general, the workers' cardiopulmonary parameters increased during respirator wear, probably because of a combination of factors, including the increased exercise of most respirator-requiring tasks and the weight and heat stress associated with the respirator and protective clothing. When the ventilatory parameters with and without a respirator were compared at the same heart rates, no significant differences were noted in VT for the entire group. Respiratory frequency, however, and V increased with respirator wear. The effects of respirators alone were found to be commonly confounded in the workplace by changes in protective clothing, exercise requirements, and ambient heat stress. Further improvements in the portable RIP system are needed before it can be accepted as a reliable ventilatory measurement device in the workplace.

Adult↗
PubMed1988

The use of inductive plethysmography in the study of the ventilatory effects of respirator wear.

The authors recently developed an ambulatory system, in which a self-contained respiratory inductive plethysmograph (RIP) was used, to measure noninvasively the volume and time components of breathing. Since it does not use nasal or oral devices, such a system is particularly suitable for use in studying the effects of respiratory protective masks on respiratory parameters. In order to validate this portable system, 22 healthy subjects were exercised on a treadmill; RIP and pneumotachographic minute ventilation measurements were compared. A short, graded submaximal exercise protocol was run 3 times by each subject under each of the following conditions: no oral mouthpiece; oral mouthpiece with pneumotachograph; and wearing an industrial protective mask (half facepiece, twin cartridge). Chest and abdominal RIP signals, a time signal and either a pneumotachograph or heart-rate signal were recorded on a small cassette recorder worn at the belt. The data tapes were later edited and analyzed by computer. Data from 5 subjects were excluded because of equipment malfunction. The average error in RIP-measured ventilation compared to values simultaneously measured by a pneumotachograph in the 17 remaining subjects over all exercise levels was -3.16%. Marked variability (SD = 11.26%), however, was found in individuals at different exercise levels and especially between subjects. Use of a respirator was associated with a decreased respiratory frequency, an increased tidal volume and minute ventilation, and an unchanged heart rate. At present, the portable RIP system has substantial variability that limits its ability to measure ventilation accurately.

Humans↗
PubMed1987

Inhaled endotoxin and decreased spirometric values. An exposure-response relation for cotton dust.

The early stages of byssinosis, the chronic lung disorder caused by the inhalation of cotton dust, are characterized by repeated episodes of mild and reversible obstruction of airways on exposure to cotton dust. To define the relation between exposure to endotoxin and the airway response to inhaled cotton dust, we pooled and analyzed data from several previous studies of experimental exposure. The pooled data set involved a total of 108 separate sessions of exposure to dust and 32 different cottons. Each dust-exposure session had involved exposing a group of 24 to 35 prescreened healthy subjects to dust from one of the cottons for six hours. The following data were obtained for each session: average concentrations of airborne dust (range, 0.12 to 0.55 mg per cubic meter) and endotoxin (range, 6 to 779 ng per cubic meter) as determined in air samples collected by vertical elutriators, and group mean percentage change in forced expiratory volume in one second (range, +0.5 to -9.1 percent), as determined by preexposure and postexposure spirometry. When data from the 108 exposure sessions were pooled, the dust concentration was not correlated with the group mean percentage change in forced expiratory volume in one second (r = -0.08; P = 0.43). In contrast, a clear exposure-response relation was observed between endotoxin concentration and group mean percentage change in forced expiratory volume in one second (r = -0.74; P less than 0.0001). Logarithmic transformation of endotoxin values clarified this relation at low-exposure concentrations and improved the correlation (r = -0.85; P less than 0.0001). Our observations strongly support the hypothesis that endotoxin has a causative role in the acute pulmonary response to inhaled cotton dust.

Adult↗
PubMed1987

Spirometry variability criteria--association with respiratory morbidity and mortality in a cohort of coal miners.

To clarify the association between spirometry variability and respiratory morbidity and mortality, the authors analyzed data for miners examined in the first round of the National Coal Study, 1969-1971, and they compared groups of miners who failed with those who met each of two spirometry variability criteria: a 5% criterion recommended by the American Thoracic Society, and a 200 ml criterion used in prior research studies. Compared with miners who met the 5% criterion (the best two forced vital capacities must be within 5% or 100 ml of one another), the group that failed had a lower mean for forced expiratory volume in one second (FEV1), and odds ratios for cough, phlegm, wheeze, shortness of breath, and death of 1.75, 1.67, 1.76, 2.71, and 1.30, respectively. The findings for the 200 ml criterion (the best two FEV1s must be within 200 ml of one another) were somewhat different. The group that failed versus the group that met this criterion had a higher mean for FEV1, and odds ratios for cough, phlegm, wheeze, shortness of breath, and death of 1.13, 1.07, 1.15, 1.43, and 0.94, respectively. Although the findings differ for the two criteria, the findings demonstrate that increased spirometry variability is associated with poorer health.

Adult↗
PubMed1986

Pulmonary function testing in the screening of workers: guidelines for instrumentation, performance, and interpretation.

Medical surveillance of workers exposed to potential respiratory hazards may be a valuable tool in early recognition and prevention of certain occupational lung diseases. The use of pulmonary function tests, particularly spirometry, has been widely accepted as an integral part of respiratory surveillance. A National Aeronautics and Space Administration contract report on the Occupational Safety and Health Administration medical and workplace surveillance requirements and recommendations by the National Institute for Occupational Safety and Health is a recent detailed study of medical surveillance requirements and recommendations (unpublished study, 1983). This paper is a brief guide for those in the medical profession attempting to establish or improve their medical surveillance programs for occupational respiratory diseases. It describes procedures to use and techniques for interpreting test results, and finally includes a study of normal reference values. In addition, the references should provide additional information for establishing a respiratory medical surveillance program.

Female↗
PubMed1986

Human ventilatory response to washed and unwashed cottons from different growing areas.

Thirty volunteer subjects were exposed to controlled amounts of respirable dust generated by the carding of cotton in an experimental cardroom. Eighteen exposures each lasting six hours were performed while carding unwashed and washed cottons from the three major growing regions of the United States. Elutriated dust was analysed gravimetrically and was comparable (0.59 mg/m3 +/- 0.04) for all exposures. Spirometry was recorded before and after each exposure. California cotton resulted in a significantly smaller fall in FEV1 than cotton of the same grade from Texas or Mississippi. All washed cottons resulted in reduced declines when compared with unwashed cottons. For 17 subjects breathing zone personal total dust samples were analysed for airborne endotoxin and compared with the individual's pulmonary function response. A significant correlation between endotoxin exposure and acute decrease in FEV1 was seen. The effect on FEV1 per nanogram of airborne endotoxin was greater for Mississippi cotton than for cotton from the other regions. Airborne endotoxin appears to be an important determinant of acute pulmonary effects of cotton dust. Water washing of cotton results in reduced airborne endotoxin and less bronchoconstriction.

Byssinosis↗
PubMed1986

Effect of spirometer temperature on measurement of FEV1 shift changes.

Spirometric parameters are generally obtained at ambient (spirometer) temperature pressure saturated (ATPS) and then converted to body temperature pressure saturated (BTPS) by multiplying each observed value by a BTPS correction factor. At ambient temperatures of 23 degrees C or higher, the accepted practice of using a constant BTPS factor introduces a relatively small error in forced expiratory volume in one second (FEV1), but as the temperature decreases below 23 degrees C the error in FEV1 increases. A dynamic BTPS correction factor model has recently been developed to reduce this error. Analysis of across-shift spirometry data from a recent survey indicates that, with an increase in temperature over a work shift of greater than 3 degrees C, 27.1% of 302 subjects were classified as having a greater than or equal to 5% FEV1 drop over the shift using the dynamic BTPS factor model, compared with 41.4% when the standard BTPS correction factor was used (P less than .005). These results indicate the importance of correcting for ambient temperature differences when analyzing for shift changes in spirometric parameters.

Body Temperature↗