Physiologic effects and measurement of carbon dioxide and oxygen levels during qualitative respirator fit testing

Abstract

In the United States, two commonly used qualitative respirator fit test methods require the use of a test hood to be placed over the subject's head and shoulders. Workers fit tested by this method have commented on the discomfort of being inside the test hood. This study was designed to quantify some parameters that might lead to these types of comments. For this study, subjects performed a series of four respirator fit tests. A quantitative and a qualitative fit test were performed with a full facepiece respirator. Then a quantitative and a qualitative fit test were performed with an N95 filtering facepiece respirator. Parameters measured include: subjects’ height, weight, and age, oxygen and carbon dioxide levels, air temperature, heart rate, arterial oxygen saturation, and Borg Ratio Scale value on breathing exertion. Carbon dioxide levels are significantly higher and oxygen levels are significantly lower in the respirator when the test hood is used during the qualitative fit test. This was especially true when fit testing filtering facepieces where mean carbon dioxide levels rose to 4.2% and mean oxygen levels dropped to 15.5%. Full facepiece respirators had similar changes, but to a lesser magnitude. The temperature inside the test hood rose an average 7.5 °F in the course of the qualitative fit test of the N95 filtering facepiece device. These stressors are not present to such an extent during a quantitative respirator fit test. Professionals conducting respirator fit tests should be aware of the physiological burdens that may occur during the qualitative respirator fit test. Some groups may be especially sensitive to this test such as the elderly, pregnant women, persons with pulmonary and/or cardiac disease, or persons with psychological disorders such as anxiety, panic disorders, or claustrophobia.