Repeated sensor use for regional cerebral oxygenation measurements by near-infrared spectroscopy: a technical report

Objective: Near-infrared spectroscopy (NIRS) has been used in clinical practice to assess regional cerebral tissue oxygen saturation (Stco(2)). There is no evidence whether repeated use of the same sensor affects Stco(2) measurements. We aimed to assess whether there was a significant systematic decrease or increase in Stco(2) when NIRS sensors were reused. Design: Participants were divided into three groups (A, B and C). Stco(2) was recorded over 5 minutes daily for 5 days in Groups A and B ("new-sensor" [NS] period; sensor age, 1-5 days) and in Groups A and C, with the sensor previously used for A ("extended-use" [EU] period; sensor age, 6-10 days). Setting: Single-centre, university hospital, intensive care unit. Participants: Healthy volunteers. Main outcome measures: Stco(2) change within and between study periods. Results: In 13 participants (9 male; median age, 30 years), the range of median Stco2 values per day was 65-72%. In the NS period, there were no changes in right-sided Stco(2), and left-sided Stco(2) showed no systematic or progressive patterns of increase or decrease when comparing Day 1 with subsequent days. There were no differences when comparing Day 1 with subsequent days (up to Day 10) in the EU period or between the NS and EU periods for left or right Stco(2). Conclusions: Repeated use of NIRS sensors measured Stco(2) in different individuals for up to 10 days. There were no significant, systematic, persistent or progressive changes in Stco(2) with extended use over time. Our findings suggest that Stco(2) does not change with sensor reuse for up to 10 days.