RT Journal Article
SR Electronic
T1 Precision and Accuracy of Oxygen Flow Meters Used at Hospital Settings
JF Respiratory Care
FD American Association for Respiratory Care
SP 1071
OP 1075
DO 10.4187/respcare.01230
VO 57
IS 7
A1 Josy Davidson
A1 Claudia Gazzeta
A1 Luciano C Torres
A1 José R Jardim
A1 Oliver A Nascimento
YR 2012
UL http://rc.rcjournal.com/content/57/7/1071.abstract
AB BACKGROUND: Oxygen therapy is an important therapeutic resource for patients with hypoxemia. When changing oxygen flow meters, we have observed that sometimes, even with the same oxygen flow setting as before, a different SpO2 is obtained. OBJECTIVE: To analyze the precision and accuracy of flow meters used in hospital settings. METHODS: An experimental study was performed to test oxygen flow meters from a tertiary hospital, by using a calibrated flow analyzer. Used and new flow meter accuracy was tested by reading in the gas analyzer a single measurement at flow rates of 1, 3, 5, and 10 L/min in 91 flow meters, and they were compared using the Student t test or Mann-Whitney U test. Flow meter precision was tested by reading in the flow analyzer 3 repetitive measurements set at flow rates of 1, 3, 5, and 10 L/min in 11 flow meters, and the reproducibility of these measurements was conducted by using the intraclass correlation coefficient and the Friedman test. RESULTS: The mean measured flow rates were slightly lower than the stipulated flow rate at 1 L/min, very close for 3 L/min, and higher for the 5 and 10 L/min flow rates. There was a large variability among the measurements from different flow meters, mainly at low flow rates (1 and 3 L/min). There was no difference between new and used flow meters at the flow rates measured, except at 10 L/min. Flow meters precision analysis showed a good reproducibility in 3 repetitive measurements for each flow rate (minimum 0.95, maximum 0.99 intraclass correlations). CONCLUSIONS: The flow meters tested showed good precision and poor accuracy.