OC115: Intracerebral regional distribution of blood flow in response to acute hypoxemia in growth‐restricted human fetuses

Objective: The atrial contraction wave is the single most important component of the ductus venosus (DV) indices used in predicting acidosis and adverse outcome. Based on the assumption that some pre-terminal changes in cardiac compliance and performance are rather reflected in the systolic and early diastolic components of the DV waveform, we aimed to establish and test new indices suitable for clinical use. Methods: DV velocities of 381 low-risk pregnancies were used to establish reference ranges for systolic pulsatility [DV-SPuls = (systolic peak − systolic nadir)/systolic peak] and early diastolic pulsatility [DV-DPuls = (diastolic peak − systolic nadir)/diastolic peak]. The DV-SPuls and DV-DPuls were determined in 123 cases where the DV Doppler recording was done ≤2 days before Cesarean section and where arterial cord pH and base excess (BE) were available at delivery, and in 15 cases of intrauterine fetal death (IUD). Power-transformation was used to achieve normality and fractional polynomial regression to calculate reference ranges, and SD-score statistics to assess deviation from the reference means. P < 0.05 was considered significant. Results: Arterial cord pH < 7.15 (n = 12), BE <−8.7 (n = 10), and particularly IUD (n = 15) were associated with increased DV-SPuls and DV-DPuls (overall p < 0.0001, and no overlap of 95%CI) when compared with the reference population. The DV-SPuls and DVDPuls were particularly high in cases with IUD (means were 2.4 and 3.1 SDs above means for the reference population) and also significantly higher than in fetuses that had arterial cord pH < 7.15 and BE <−8.7 (no overlap of 95%CI). Conclusions: Changes in the ductus venosus waveform during systole and early diastole are linked to alterations in acid base status at birth and intrauterine death. Augmented pulsations in this part of the DV wave may give valuable additional information on pre-terminal deterioration of the fetal circulation.