Cord blood gas is a medical test used to determine the levels of dissolved gases in umbilical cord blood. This test is administered shortly after birth in cases where there are concerns about oxygen deprivation during labor and delivery. If the test shows that a baby has low oxygen levels, extra measures can be taken to provide appropriate support and treatment to the baby, reducing the risks of complications related to hypoxia, the medical term for oxygen deprivation.
In a cord blood gas test, the clamped umbilical cord is carefully sampled with a needle. Venous and arterial cord blood samples can both be taken. The sample is transported to a lab, where it is tested to determine the dissolved gas level. This testing can be conducted very rapidly, providing fast feedback to care providers so they can make decisions about handling and treatment of the infant in a timely fashion.
Doctors can request a cord blood gas if they are concerned that an infant may have been deprived of oxygen during labor or shortly after delivery. The test provides immediate information for patient care, and serves a medico-legal function by creating an entry on the patient's record showing that there were concerns about oxygenation for the baby, and a test was run to collect more information and determine the best course of action. This information can be beneficial in the event of a lawsuit regarding the birth.
This test can be performed by a medical professional with some basic training in how to handle the umbilical cord. It is important to handle with care, as damaging the cord during the test can make it impossible to recover a specimen of cord blood. The sample is usually taken with a heparinized syringe, a syringe with a small solution of heparin inside to prevent the blood from clotting, ensuring it can be tested in the lab.
Once a cord blood gas reading is obtained, the doctor can decide if the patient needs oxygen or any additional interventions. The reading is also recorded in the patient's chart along with other information about the labor and delivery process, ensuring that this material will be available for future reference.
Parents should not necessarily be worried if a cord blood gas test is ordered. Like other tests used partially for medico-legal reasons, a doctor may request the test just to be safe, not because there is an immediate concern.