What is the effect of meconium, blood, or vernix?
Meconium-stained skin has an insignificant affect on fetal pulse oximeter readings. The effect of meconium-staining on light absorption does not change with pulsation so it is subtracted during signal processing in the same manner as is absorption due to venous blood. The same is true for blood and vernix. Typically, meconium and blood do not adhere to the sensor’s contact electrodes or optical components, so they do not present a problem. However, if such materials are present in sufficient quantity to interfere with the normal operation of the “sensor lifted” indicator, optical shunting (light reaches the photodetector without passing through tissue) can occur and readings may be affected.
