Search PubMed⌕ Search

Biomedical subjects

N L Lapp

Publications and source records attributed to N L Lapp.

At least 37 records · Page 2Linked to original sources
PubMed1985

Endoscopic laser therapy for respiratory distress due to obstructive airway tumors.

Neodymium-YAG laser therapy for unresectable malignant airway obstructions has a promising future. Nine patients with moderate to severe respiratory distress all experienced rapid relief of dyspnea and substantial improvement in pulmonary function within hours to days after treatment with laser phototherapy. The quality of life and survival was improved in otherwise hopeless cases. A nonfatal case of pneumothorax was the only major complication.

Adult↗
PubMed1983

Silicosis in surface coalmine drillers.

Surface coalminers are generally thought to be at minimal risk of developing pneumoconiosis. Biopsy-proved silicoproteinosis was found in a 34-year-old surface coalmine driller, and two of nine other drill crew members who worked for the same company had chest radiographic findings compatible with simple silicosis. Reanalysis of data from a previous United States Public Health Service survey of surface coalminers, after exclusion of those with underground mining experience, showed that 38% of the cases of pneumoconiosis occurred in drill crew members, a group comprising only 11% of the study population. On the basis of these data surface coalmine drillers appear to have an increased risk of developing occupational lung disease.

Adult↗
PubMed1982

Pulmonary function in infectious mononucleosis.

Infectious mononucleosis (IM) is common among students. These patients often complain of fatigue and dyspnea. To determine whether IM alters respiratory function, we performed spirometric, single-breath diffusing capacity, and maximal static respiratory pressure tests on seven patients with symptoms of IM. These studies were repeated two weeks later and the respiratory pressures were repeated five months later. Each patient served as his own control. Pulmonary function was normal except for respiratory pressures, which were initially low. These pressures, still low after two weeks, improved significantly after five months. We concluded that IM is associated with transient respiratory muscle weakness.

Adolescent↗
PubMed1980

Respiratory disability in coal miners.

It has been suggested that the assessment of ventilatory capacity alone is inadequate for the determination of disabling occupational respiratory impairment in coal miners. The Department of Labor has accepted this view and now routinely requests blood gas analyses in those claimants not meeting the ventilatory criteria. We tested the validity of this contention by selecting two groups of coal miners claiming total disability. The first consisted of 150 claimants who were referred for spirometry, while the second consisted of 50 claimants who had been referred for blood gas studies. Of those in group 1, eight met the extent criteria for disability, while only two of those in group 2 satisfied the criteria, and, in both, cardiac disease was responsible. We conclude that blood gas analyses are unnecessary in the determination of pulmonary disability in coal miners.

Blood Gas Analysis↗
PubMed1980

Acute massive unilateral hydrothorax: a rare complication of chronic peritoneal dialysis.

We have described a case of massive unilateral hydrothorax during chronic peritoneal dialysis. The communication between the peritoneal and right pleural cavities was confirmed by injection into the peritoneal cavity of methylene blue, which promptly appeared in the pleural cavities. Peritoneal dialysis was continued, using decreased dialysate and a semisitting position. The possibility of continuing peritoneal dialysis in the patient with acute hydrothorax and in whom hemodialysis may be contraindicated is demonstrated.

Adult↗
PubMed1979

Effect of body position on gas exchange after thoracotomy.

To determine the effect of change in body position on gas exchange after thoracotomy, 12 patients with potentially resectable lung tumours were studied before and 24 hours after operation. Measurements of arterial blood gas tension (PaO2, PaCO2), alveolar-arterial oxygen difference (A--adO2), venous admixture effect (Qs/Qt percent), and physiological dead space to tidal volume ratio (Vd/Vt), were made in the supine, and left and right lateral decubitus positions. Preoperatively, altering position did not affect gas exchange significantly. After thoracotomy in the lateral position with the unoperated side dependent, PaO2 was significantly higher, and A--adO2 and Qs/Qt percent significantly lower than in the supine position. Postoperatively, the lateral position with the side of thoracotomy dependent was usually associated with the worst gas exchange. Only three patients achieved their best postoperative gas exchange in this position. In two this may have resulted from dependent small airway closure during tidal breathing, due to airways obstruction and old age, and in the third from postoperative atelectasis in this unoperated lung. No significant changes in mean PaCO2, Vd/Vt, or minute ventilation (VE) occurred with different positioning.

Aged↗
PubMed1976

Significance of irregular small opacities in radiographs of coalminers in the USA.

The purpose of this study was to determine the factors that are associated with the occurrence of small irregular opacities in the chest radiographs of coalminers, and whether the lung function of miners with irregular opacities differed from that of miners with small rounded opacities, a mixture of small rounded and irregular opacities, or an absence of opacities. A subsample of 6166 coalminers was selected from 9076 miners who had been examined by the US Public Health Service as part of the National Study of Coalworkers' Pneumoconiosis. The subsample consisted of 4479 smokers and 1687 non-smokers. The chest radiograph of each miner was classified according to the UICC/Cincinnati Classification.

Adult↗
PubMed1976

Closing volume in coal miners.

Closing volume and closing capacity were determined in 82 working Appalachian coal miners and in a comparable group of control subjects. Abnormalities of closing volume and closing capacity were related to other measurements of pulmonary function. The relationship of smoking history, dust exposure, and presence of pneumoconiosis and bronchitis to elevations of closing volume and closing capacity was determined. It was shown that nonsmoking miners had elevated closing volume and closing capacity when compared to control subjects. Miners who were smokers or ex-smokers also had elevated closing capacity when compared to control subjects. Neither bronchitic symptoms nor the radiographic presence of pneumoconiosis were associated with an elevation of closing volume or closing capacity.

Bronchitis↗
PubMed1976

Severe airway disease due to inhalation of fumes from cleansing agents.

A subject had severe airway obstruction and evidence of small-airway disease resulting from inhalation of "fumes" liberated during the course of mixing several drain-cleansing agents. The evidence in favor of the airways as the predominant site of damage was severe reduction of maximal expiratory flow in the presence of normal lung-recoil pressure in a nonsmoker who had no other known industrial exposures or predisposing respiratory conditions.

Acids↗
PubMed1975

Polyvinyl chloride pyrolysis products. A potential cause for respiratory impairment.

A limited investigation of respiratory and other symptom prevalence, plus before and after shift ventilatory capacity was conducted among a group of 17 meat wrappers exposed to pyrolysis products of polyvinyl chloride and a group of 21 control subjects. Exposed meat wrappers showed a higher prevalence of cough, phlegm, hay fever, and asthma than did the control group. The exposed group also demonstrated relative decreases in forced expiratory volume, one second (FEV1.0) and forced expiratory flow 50% (FEF50) after one shift of work; whereas, the controls showed an opposite tendency. These findings suggest that meat wrappers exposed to pyrolysis products of polyvinyl chloride might be adversely affected. The results, while suggestive, are not totally conclusive owing to the fact that there was not ideal matching of the exposed and control groups in regard to age, height, race, sex, and smoking status.

Age Factors↗
PubMed1975

Pilot study of closing volume in byssinosis.

A study of the relative sensitivities of forced expiratory volume in one second (FEV1), maximal mid-expiratory flow (MMF), and closing volume (CV) in the detection of subjects with byssinosis was carried out in a North Carolina cotton mill. Altogether 35 workers participated in the study. Of these, nine showed a decline in FEV1 of 10% or more during the first work shift that followed the weekend break. Twelve subjects showed a decrease in MMF of 15% or more. In contrast only six workers exhibited a 10% increase in closing capacity, while ten showed a 10% increase in CV. Recent evidence of the magnitude of variability in closing volume manoeuvres suggests that our chosen level of change was too low, A 40% change in CV would have identified only five subjects. CV is a more complex manoeuvre for the subject being tested and for the technician to perform, is more time consuming, and is subject to greater variation. To have any advantage over spirometry, CV would have to be appreciably more sensitive. Our study suggests that it is not. However, the MMF may prove to be more sensitive than the FEV1 in the detection of byssinosis.

Byssinosis↗
PubMed1975

Variability in the size of airspaces in normal human lungs as estimated by aerosols.

Measurement of persistence, expressed as half-life (t1/2), of a monodisperse aerosol during breath holding was interpreted as an indirect estimate of the size of intrapulmonary airspaces in healthy subjects. Within subject variation of t1/2 measured over a period of nearly two years was small (coefficient of variation 7-7 to 11-5%). Mean effective airspace diameters were calculated from the aerosol t1/2 values using the settling term from the equation of Landahl (1950). Calculated mean airspace diameters ranged from 0-30 to 0-79 mm for 36 males and from 0-40 to 0-62 mm for 12 females. Airspace diameters correlated poorly with age, height, weight, and lung volumes. These results suggest marked differences in airways geometry in subjects with similar heights and lung volumes.

Adult↗
PubMed1975

Factors influencing the measurement of closing volume.

The various factors influencing closing volume were studied by performing the single-breath N2 test on 9 healthy nonsmokers. Time of day, day of the week, and preceding volume history had no effect on either closing volume or alveolar plateau. Slow inspiratory flow resulted in larger ratio of closing volume to vital capacity, ratio of closing capacity to total lung capacity, and change in N2 concentration than fast inspiratory flow. Voluntary regulation of the expiratory flow resulted in smaller ratios of closing volume to vital capacity and closing capacity to total lung capacity than when flow was regulated by a resistance. Prolonged breath holding of the inspired O2 led to larger ratio of closing volume to vital capacity and ratio of closing capacity to total lung capacity. To obtain uniform, comparable closing volumes, it is suggested that the subject inspire slowly, control expiratory flow (preferably voluntarily), and not pause between inspiration and expiration.

Adult↗