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Biomedical subjects

G S Rajhans

Publications and source records attributed to G S Rajhans.

9 recordsLinked to original sources
PubMed1989

Hygiene aspects of occupational exposure to waste anaesthetic gases in Ontario hospitals.

Exposure of workers to waste anaesthetic gases in the operating and recovery rooms of hospitals is an ongoing concern because a number of epidemiological and mortality studies have reported significant adverse effects. To evaluate the health risks if any, and to assist in the development of guidelines or regulations for the hospital sector in Ontario, the Health and Safety Support Services Branch of the Ontario Ministry of Labour conducted this extensive study. The results of the hygiene study show that exposure to waste anaesthetic occurs because of leaks in the anesthetic equipment. The three major sources of leaks (i.e. exhalation valves, masks and high-pressure fittings) produced concentrations above the limit of detection of nitrous oxide (1000 ppm of N2O) in a significant number of samples. Of the samples taken at leak sources those taken at the exhalation valve had the highest percentage of samples above 1000 ppm, which suggested that scavenging systems were not receiving proper service and maintenance. Only 23% of the operating rooms surveyed met the Ontario Ministry of Health Criterion of 24 air changes per hour. Dilution ventilation was less effective than scavenging in keeping down concentrations of air contaminants. The sampling data show that the anaesthetists have the highest time-weighted average exposure (median value range 56-79 ppm) of the major group of occupations surveyed and that the general surgeons' TWA is much lower (28 ppm). It was concluded that the dilution ventilation rate of 24 air changes per hour should be maintained in all operating rooms and that there should be no recirculation of exhaust air when operations are in progress. To keep down concentrations of anaesthetic gases scavenging systems should be provided in all operating rooms. In each hospital maintenance should be the responsibility of a qualified staff member who has been adequately trained in the repair and maintenance of anaesthetic delivery systems. Finally, a qualified staff member should be responsible for conducting periodic personal monitoring in operating rooms (ORs) and recovery rooms (RRs) and the sampling strategy should include individuals and the exhaust grilles.

Air Pollutants, Occupational↗
PubMed1978

Silica flour exposures in Ontario.

A total of 16 cases of silicosis are reported in Ontario plants where there was exposure to silica flour. Dust counts expressed as mppcf are shown for four of these plants taken over a period of 37 years. A relationship has been obtained experimentally to permit conversion of the counts to respirable mass concentrations. Based on the information obtained, a TLV of 0.05 mg/m3 for silica flour is proposed.

Air Pollutants↗
PubMed1975

A statistical analysis of asbestos fiber counting in the laboratory and industrial environment.

The reproducibility of standard fiber counts in the laboratory and four industrial plants is discussed in detail. Under field conditions the standard deviation of the results varied between 0.4-1.2 f/ml. Under ideal laboratory conditions the standard deviations of the counts were approximately 0.2 f/ml. It is concluded that the standard method is sufficiently precise for industrial measurements.

Air Pollutants↗
PubMedDate not supplied

A review of health risks in acrylonitrile industry.

The Occupational Health Branch of the Ontario Ministry of Labour began a study in 1978 for the evaluation of health risks associated with acrylonitrile (AN) exposure. Detailed hygiene and medical investigations were conducted in fourteen plants for evaluating AN exposure in various industrial processes. For companies were also studied in relation to mixed chemical exposure representing acrylic fibres, nitrile rubber, ABS-resin, and acrylic emulsions production. The possible interaction between AN and other coexisting chemical exposures was reviewed since dimethyl formamide, styrene, and butadiene have similar pharmacokinetics and possible synergistic effects. Exposure in acrylic fibre production may be synergistic and carcinogenic. Results of air monitoring indicated exposure levels to AN below 2 ppm (TWA) in most cases. Exposure to other co-existing chemicals was evaluated. Results of medical tests indicated no significant abnormalities in chest x-rays or liver function tests in currently exposed workers.

Acetamides↗