A conversion formula for comparing pulse oximeter desaturation rates obtained with different averaging times

Area of Science:

• Neonatal physiology
• Medical device technology
• Data analysis

Background:

• Pulse oximeter saturation (SpO2) desaturation rates vary due to non-standardized averaging times.
• This variability hinders comparability of SpO2 data between different clinical centers.
• A method to standardize desaturation rate reporting is needed.

Purpose of the Study:

• To develop a formula for converting desaturation rates recorded with different pulse oximeter averaging times.
• To enable standardized comparison of SpO2 data across institutions.
• To account for various desaturation levels and minimal durations.

Main Methods:

• Raw pulse oximeter data from 12 preterm infants (170 hours) were reprocessed using 7 averaging times (3-16s).
• Desaturations were analyzed for 7 minimal durations and 3 SpO2 thresholds (80-90%).
• A conversion formula was derived and validated using training and test sets.

Main Results:

• A formula D2 = D1 (T2/T1)(c) was established, based on the logarithmic relationship between desaturation rate and averaging time.
• The exponent 'c' is dependent on desaturation threshold and minimal duration.
• The formula demonstrated a median error of 2.6% in validation.

Conclusions:

• The derived formula effectively converts desaturation rates between different averaging times.
• This facilitates standardized SpO2 data interpretation in clinical practice.
• Applicable across various desaturation thresholds and minimal durations.