137 Transcutaneous ear probe oxygenation readings are significantly higher than finger probe oxygenation readings in CF adults

Abstract

Objectives: Accurate assessment of oxygen saturations (SaO2) is vital in the management of people with CF. Capillary blood gases (CBGs) are relatively painless and correlate well with arterial blood gases (ABGs) when estimating SaO2 in chronic lung disease [1]. Finger probe pulse oximetry (SpO2) is routinely used to estimate SaO2, but over the last 12 months we have started using ear probe pulse oximetry in our large regional CF centre. Our objective was to compare SaO2 by CBG or ABG with finger and ear probe SpO2 in adults with CF and normal controls. Methods:We performed simultaneous CBG or ABG, finger and ear probe SpO2 in adults with CF and normal controls. Finger and ear probe SpO2 were recorded by the same oximeter (Nonin Medical Inc.) using the appropriate sensors. Results: 21 sets of observations (19/21 CBGs) were recorded in 14 patients (6 male, mean age 29yrs, mean FEV1 30% predicted). 3 sets of observations (3/3 CBGs) were performed in 3 normal controls (1 male, mean age 31yrs). In patients ear probe SpO2 was significantly higher than finger probe SpO2 (*p < 0.001) and finger probe SpO2 was significantly lower than SaO2 (^p =0.01).