PubMed Health⌕ Search

Biomedical subjects

K P Fennelly

Publications and source records attributed to K P Fennelly.

6 recordsLinked to original sources
PubMed1998

The relative efficacy of respirators and room ventilation in preventing occupational tuberculosis.

OBJECTIVES: To evaluate the relative efficacy of personal respiratory protection as the concentrations of infectious aerosols increase or as room ventilation rates decrease. METHODS: We modified the Wells-Riley mathematical model of airborne transmission of disease by adding a variable for respirator leakage. We modeled three categories of infectiousness using various room ventilation rates and classes of respirators over a 10-hour exposure period. RESULTS: The risk of infection decreases exponentially with increasing room ventilation or with increasing personal respiratory protection. The relative efficacy of personal respiratory protection decreases as room ventilation rates increase or as the concentrations of infectious aerosols decrease. CONCLUSIONS: These modeling data suggest that the risk of occupational tuberculosis probably can be lowered considerably by using relatively simple respirators combined with modest room ventilation rates for the infectious aerosols likely to be present in isolation rooms of newly diagnosed patients. However, more sophisticated respirators may be needed to achieve a comparable risk reduction for exposures to more highly concentrated aerosols, such as may be generated during cough-inducing procedures or autopsies involving infectious patients. There is probably minimal benefit to the use of respirators in well-ventilated isolation rooms with patients receiving appropriate therapy.

Air Microbiology↗
PubMed1998

Irritant-associated vocal cord dysfunction.

Vocal cord dysfunction (VCD) is a poorly understood entity that is often misdiagnosed as asthma. We report eleven cases of VCD in which there was a temporal association between VCD onset and occupational or environmental exposure. We conducted a case-control study to determine if the characteristics of irritant-exposed VCD (IVCD) cases differed from non-exposed VCD controls. Chart review of VCD patients at the authors' institution produced 11 cases that met IVCD case criteria. Thirty-three control VCD subjects were selected by age matching. There were statistical differences between the groups in ethnicity and chest discomfort. There were no statistical differences between the groups for gender, tobacco, smoking habits, symptoms, or pulmonary function parameters. Varied irritant exposures were associated with IVCD. IVCD should be considered in patients presenting with respiratory symptoms occurring after irritant exposures.

Adult↗
PubMed1997

Personal respiratory protection against Mycobacterium tuberculosis.

Although there are no data demonstrating the effectiveness of personal respiratory protection in the prevention of occupational tuberculosis, there are sound theoretical bases supporting the use of respirators to reduce the risk of inhalational exposure. The major factor that limits the effectiveness of most respirators is the leakage between the face and the mask. There are data suggesting that traditional fit testing of respirators does not adequately predict the degree of protection in actual use, and more research is needed in that area. There is a large range of infectiousness of aerosols of TB, and classes of respirators vary greatly in the degree of protection they offer. I have argued that respirator selection should be based on anticipated exposures. High-risk exposures to TB are often associated with cough-inducing procedures or with aerosolization of infected tissues during autopsies. In my opinion, the most reasonable type of respirator for such high-risk situations in health care settings is a PAPR hood. The concentration of infectious aerosols in well-ventilated respiratory isolation rooms is likely to be very low, and the new N95 respirators offer a reasonable balance of comfort, cost, practicality, and protection. Preliminary data from mathematical modeling studies suggest there may be little additional benefit from more sophisticated personal respiratory protection in such settings. Additional research is needed to more accurately assess exposures to TB, to determine the size and aerodynamic behavior of TB generated by infectious patients, and to more accurately define the role and effectiveness of personal respiratory protection against TB.

Cost-Benefit Analysis↗