The Utility of Umbilical Cord Pulse Oximetry—A Translational Study with Four Minutes of Deferred Cord Clamping Using an Asphyxiated Preterm Ovine Model

Highlights: What are the main findings? Umbilical pulse oximetry is a novel method to measure umbilical cord saturations in newborns. Umbilical saturations and umbilical heart rate through pulse oximetry, although postductal, had a significant correlation with arterial saturations and invasive carotid heart rate measurements. What is the implication of the main finding? Umbilical cord pulse oximetry could serve as an alternative to measure oxygen saturation while undergoing a longer duration of deferred cord clamping. Umbilical cord pulse oximetry may help decide the duration of deferred cord clamping in the future. Background: Expert guidelines recommend using pulse oximetry (PO) in the delivery room to monitor oxygen saturation (SpO₂) and heart rate (HR). Umbilical cord pulse oximetry (UCP) is a novel concept that, despite being postductal, could provide accurate measurements of SpO₂ and HR, as it overcomes barriers associated with skin pigmentation. Methods: This pilot study used NONIN pulse oximetry on an intact umbilical cord that underwent deferred cord clamping (DCC) to evaluate umbilical cord SpO₂ in a preterm asphyxiated ovine model (N of 5) with an HR of <100 bpm. The UCP HR served as a surrogate marker for umbilical vessel flow. A receiver operator characteristic (ROC) curve was used to evaluate UCP parameters with arterial saturations (SaO₂) and carotid HR between 2 and 10 min. Results: Following asphyxia, five preterm lambs underwent DCC for 4 min. A significant relationship was noted between SaO₂ and umbilical SpO₂ (area under the curve (AUC) of 0.907, CI 0.857–0.968, p < 0.0001) along with carotid and umbilical HR (AUC) of 0.842 (CI 0.663–0.902, p < 0.0001). Conclusions: In a translational preterm model, UCP accurately predicted preductal SaO₂ and carotid HR (a surrogate for umbilical flow). Using UCP in the delivery room will help guide supplemental oxygen and determine the optimal duration of clamping the umbilical cord. These proof-of-concept studies/pilot findings require validation with larger animal cohorts and newborn infants.