2002 OPEN FORUM Abstracts
THE ACCURACY OF OXYGEN FLOWMETERS IN CLINICAL USE
Cindy Peters, Prayoun Poulima, Respiratory Therapy Students, Indiana University, Deb Pearson, RRT, IU/Riley Respiratory Care, Clarian Health, Linda Van Scoder, EdD, RRT, Respiratory Therapy Program, School of Allied Health Sciences and Medicine, Indiana University.
BACKGROUND Oxygen is used in patients to maintain sufficient oxygenation to the tissues and to avoid hypoxemia. Therefore, it is essential to verify that the flowmeter is delivering the proper amount of flow to the patient. A review of the literature found limited data exists on Thorpe tube oxygen flowmeters. The review of the literature revealed no current information on oxygen flowmeters. Most information found regarded anesthesia vaporizing flowmeters. That research discovered inaccuracy ranges from 10-40%. The limited amount of data found on oxygen flowmeters indicated that they also tend to be inaccurate.
PURPOSE This study was conducted to find out how accurate oxygen flowmeters in clinical use are and whether they meet the Compressed Gas Association requirements.
METHODS This study included a convenience sample from three hospitals. At two of the three hospitals, 20 flowmeters were randomly chosen from different areas in the hospital. At the third hospital only 10 flowmeters were tested. The randomly selected flowmeters were then tested at different flows- 2L/min, 10L/min, 15/min and a ?flush? setting. The apparatus used to test the flowmeters was an RT-200 (Timeter) analyzer. Each flowmeter was tested twice to ensure accuracy of the reading. Four different brands of flowmeters were tested; Precision Medical, Timeter, Puritan, and Chemtron.
RESULTS We found that most of the flowmeters tested fell within the requirements set by the Compressed Gas Association (CGA). The CGA range for accuracy at 2 L/min is 1.8-2.2 L/min. The mean flows of hospitals 1, 2 and 3, were 1.69 L/min, 2.09 L/min, and 2.1 L/min respectively at a set liter flow of 2. The CGA range for accuracy at 10 L/min is 9.0-10.9 L/min. The mean flows for hospitals 1, 2 and 3 were 10.27 L/min, 10.72 L/min, and 9.75 L/min respectively. The CGA range for accuracy at 15 L/min is 13.5-16.5 L/min. The mean flows for the hospitals were 14.35L/min, 14.16 L/min, and 15.9L/min respectively. Flush settings on the flowmeters had a wide range of mean flow. At hospital 1 the mean flow was 79.67 L/min. At Hospital 2 the mean was 89.37 L/min and at hospital 3 the mean was 56.09L/min.
CONCLUSION Although the majority of the flowmeters tested fell within the requirements only a small sample was taken. A more extensive research study should be conducted to test accuracy. Research should be not only by flows but by brands as well. It can be concluded that flowmeters provide a wide variety of flush flows.