An alternate approach for fit test in identifying respiratory protection by N95 respirator

Abstract

Background: Global concern over use of N95 respirator has increased recently because of the threat of outbreaks of infectious diseases, such as avian influenza and the novel Influenza A (H1N1). The use of a fitted N95 respirator has been recommended, legislated and implemented in the USA, Canada and other countries. Perception factors or any discomfort may influence the proper use of the respirator by the wearer as the wearer may dislocate the respirator and/or use it in a non-appropriate position. The conventional quantitative fit test instruments, which give an instant measurement, have provided the gold standard for predicting the protection of an N95 respirator in a laboratory environment; however, conventional quantitative fit test instruments cannot deliver real-time measurements of faceseal leakage when the N95 respirator is in use in clinical settings. This study aimed to develop an alternate method to evaluate N95 respiratory protection in real-time, in a clinical setting. Method: Stage 1 involved developing and validating a new fit test method to evaluate respirator protection. Stage 2 evaluated (a) the performance of the investigator-developed fit test method and (b) the necessity to perform fit check, a subjective self-check method by the wearer to determine whether the respirator he/she has put on is leaking. Eighty-four subjects were selected for this study. All were first-year undergraduate students who had never performed a fit test or a fit check before being recruited for this study. They were divided randomly into four groups. The real-time fit test method was measured by two Portable Aerosol Spectrometers at the same time. The tests were conducted while the subjects were wearing N95 respirators in doing bedside nursing procedures. All subjects were asked to evaluate six perceptions (heat, breathability, tightness, ease in talking, comfort on ear lobe and overall comfort) that they experienced while doing the procedures wearing a respirator in the test. Results: Results from the work of Stage 1 showed that the two spectrometers were consistent in measuring ambient particle concentration. The one-way intraclass correlation coefficient between the two spectrometers was 0.83. Results of Stage 2 showed significant differences among groups in perception of sensation after wearing N95 respirator in terms of the ease in talking (p=0.026). This study achieved an effect size index of 0.866 which made the power analysis of the study 99%. Discussion: Health care workers are told to perform a fit check whenever donning an N95 respirator, but they often do not know how important the fit check is and do not understand the consequence of not performing the fit check. This study found that performing the fit check minimizes the air particles leaking into the respirator during nursing procedures. Personal perception of respirator, whether their feeling toward wearing respirator can affect health care workers' compliance with rules regarding protective equipment, their personal safety as well as their morale. Therefore, the respiratory protection and training programme should include thorough training in how to wear the N95 respirator; it should reinforce the importance of performing the fit check whenever donning an respirator in clinical work place, and supervised the compliance of fit check in performance of fit test. Conclusion: The investigator-developed fit test method to evaluate N95 respirator protection was devised and tested in this study. Results are promising. This investigator-developed fit test method can provide real-time measurement of the effectiveness of respiratory protective devices; it can thereby significantly reduce the risk of health care workers exposed to airborne infectious diseases if consistently used in clinical settings.