Assessing the SpO₂ in a random population - Looking for the best among fingers

Pulse oximetry is one of the most revolutionary methods used to monitor the patients in the clinical setting, particularly intensive care and anesthesia. We usually use the index or middle finger to measure SpO₂ values, but little is known about the inter-digital differences that exist between the fingers.

We aim to compare the peripheral capillary oxygen saturation among fingers of both hands. A total of 93 healthy volunteers aged between 18 and 50 years participated in the study.

Their SpO₂ values were recorded from each finger with at least 1 minute of resting interval. Their blood pressure, heart rate, and body temperature were recorded as well.

A total of 930 measurements were obtained from 93 volunteers. The highest average SpO₂ value of right-handed volunteers was measured from the left little finger (98.48 ± 0.62) of right-handed volunteers, and it was statistically significant when compared with the right ring finger, right little finger, left thumb, left index, left middle finger, and left ring finger. The highest average SpO₂ from left-handed volunteers was obtained from the right index finger, but it was statistically insignificant.

We assume ethnic and climatic differences to play a role in contradictory results noted from previous studies conducted, and this needs to be investigated further. It is recommended that multiple readings may be obtained from other fingers as well before coming to any conclusion as inter-finger variability cannot be ignored.