Re‐evaluation of cord blood arterial and venous reference ranges for pH, pO₂, pCO₂, according to spontaneous or cesarean delivery

Abstract

Umbilical cord blood gas analysis (pO(2) and pCO(2)) is now recommended in all high-risk baby deliveries and in some centers it is performed routinely following all deliveries. The aim of this study was to re-evaluate cord blood arterial and venous reference ranges for pH, pO(2), pCO(2) in newborns, delivered by spontaneous vaginal delivery (SVD) and by cesarean section (CS) performed in Faculty Hospital Motol. Two groups of subjects were selected for the study. Group I consisted of 303 newborns with SVD. Group II consisted of 189 newborns delivered by cesarean section. Cord blood samples were analyzed for standard blood gas and pH, using the analytical device Rapid Lab 845 and Rapid Lab 865. We obtained reference values expressed as range (lower and upper reference value expressed as 2.5 and 97.5 percentiles) for cord blood in newborns with SVD: arterial cord blood: pH=7.01-7.39; pCO(2)=4.12-11.45 kPa; pO(2)=1.49-5.06 kPa; venous cord blood: pH=7.06-7.44; pCO(2)=3.33-9.85 kPa; pO(2)=1.80-6.29 kPa. We also obtained reference values for cord blood in newborns delivered by CS: arterial cord blood: pH=7.05-7.39; pCO(2)=5.01-10.60 kPa; pO(2)=1.17-5.94 kPa; venous cord blood: pH=7.10-7.42; pCO(2)=3.88-9.36 kPa; pO(2)=1.98-7.23 kPa. Re-evaluated reference ranges play essential role in monitoring conditions of newborns with spontaneous and caesarean delivery.

Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans

“…It is therefore fortunate that endothelial cells isolated from these vessels have been used extensively in vascular biology in vitro, allowing for an accurate and well characterised transition to physiologically normoxic cell culture. A meta-analysis of data extracted from a number of studies reporting umbilical blood PO 2 (102,109,298,313,347,376,465,486,576,605,675) reveals a mean blood PO 2 of 3.8 and 2.4 kPa within umbilical veins and arteries, respectively. Although collected ex vivo under room air, this has been shown not to increase measured O 2 levels in umbilical blood (382).…”

“…Although collected ex vivo under room air, this has been shown not to increase measured O 2 levels in umbilical blood (382). Interestingly, umbilical vein PO 2 decreases throughout gestation from ~6 kPa at 20 weeks to ~4 kPa at 36 weeks (639), and final PO 2 at birth is significantly affected by the method of delivery (spontaneous vaginal vs caesarean) (109,313) and position of the fetus (breech) (102). The human umbilical vein is a macrovessel of 2-3 mm diameter with an average wall thickness of 430µm and a moderate adventitial layer (344).…”

The Transitional Heart: From Early Embryonic and Fetal Development to Neonatal Life

“…It is a low resistance vascular bed, which promotes the fetalto-maternal exchange of deoxygenated blood under low pressure [3,50]. Despite the low partial pressure of oxygen in the placenta, oxygen delivery to fetal tissues remains adequate due to the combined high ventricular output and the presence of fetal hemoglobin, which has a higher oxygen affinity than adult hemoglobin [50,55,56].…”

Endocannabinoid Levels in Newborns in Relation to the Mode of Delivery

“…28,29 CD showed less BE than considered normal and were thus closer to the physiological state of a newborn in the postnatal phase. 30,31 Watanabe et al 32 also measured a lower BE in newborns delivered vaginally compared with elective CD. They concluded that oxidative stress is greater in vaginal-delivered newborns.…”