Catecholamine levels and their correlation to blood gases in umbilical venous blood obtained by cordocentesis.

The plasma catecholamine concentration was evaluated in umbilical venous blood obtained by cordocentesis performed in 77 fetuses for indications including: nonimmune hydrops; Rh incompatibility; intrauterine growth retardation; polyhydramnios; anomalies; immunological disorders, and possible viral infection. The pH as well as pO2 of the umbilical venous blood showed a notably significant negative correlation with the norepinephrine concentration (r = -0.5607, r = 0.4467); while pCO2 was also significantly correlated with the norepinephrine concentration (r = 0.4955). When the pCO2/pO2 ratio was tentatively put up for comparison, the ratio was undoubtedly better correlated (r = 0.60442) with the fetal norepinephrine concentration than any other biochemical variable. Moreover, the ratio over 2.0 suggests that fetal catecholamine values have reached abnormal levels.