Reference range for tissue oxygen saturation in pregnancy using near-infrared spectroscopy

Area of Science:

• Obstetrics and Gynecology
• Physiological Monitoring
• Medical Diagnostics

Background:

• Near-infrared spectroscopy (NIRS) provides continuous, noninvasive tissue oxygen saturation (StO2) measurements.
• StO2 is valuable for predicting hypoperfusion, but normal ranges in pregnancy are not well-established.
• Establishing these ranges is crucial for accurate clinical interpretation in obstetric patients.

Purpose of the Study:

• To determine the reference range for tissue oxygen saturation (StO2) in healthy pregnant women.
• To provide a baseline for StO2 values during pregnancy using NIRS technology.
• To support the use of StO2 monitoring in predicting obstetric complications.

Main Methods:

• 154 healthy pregnant women were enrolled.
• Three sequential StO2 measurements were taken from the thenar eminence using NIRS.
• One-way ANOVA and non-parametric methods were used to establish the 95% confidence interval reference range.

Main Results:

• The overall reference interval for StO2 in pregnant women was 73% (95% CI 72-75) to 92% (95% CI 89-93).
• This range is comparable to that observed in the non-pregnant population.
• No statistically significant differences in StO2 were found between trimesters, though trimester-specific ranges could not be determined due to sample size.

Conclusions:

• A reference range for StO2 in normal pregnancy was successfully estimated.
• This data is essential for the clinical application of StO2 monitoring in obstetric care.
• The findings may enhance the ability to predict shock in pregnant patients.