12181 (102) Interpreting Umbilical Cord Blood Gases
Jeff Pomerance, MD MPH

Abstract
Umbilical cord blood gases provide insight into the presence or absence of respiratory and/or metabolic acidoses just prior to birth and, if present, into the etiology of the derangement. This information has both medical and medico-legal implications. Historic normative data for umbilical venous and arterial samples will be provided. Then, a series of umbilical cord blood gases drawn from actual patients will be presented in sequential format to facilitate development of expertise in interpretation. Cases will be reviewed that illustrate pitfalls involved in collection and handling of specimens, as well as normal and abnormal relationships between umbilical cord venous and arterial blood gas samples. Lastly, classical patterns of cord gases associated with both uterplacental insufficiency and various examples of cord compression will be presented.

Learning Objectives
1. Discuss normal umbilical cord blood gas values.
2. Cite the usual relationship between pH and blood gas values found in the umbilical vein and the umbilical artery.
3. Recognize when technical problems have occurred and how best to correctly interpret the results whenever possible.
4. Identify recurring patterns of abnormal umbilical cord blood gas values and understand the pathophysiology.
5. Recognize when asphyxia has been associated with delivery and when it has not.

Bibliography
Book: Pomerance JJ. Interpreting Umbilical Cord Blood Gases. BNMG, Pasadena, CA, 2004 - www.cordgases.com