Table 1.
Calculations 1 for blood flow, nutrient uptake, nutrient utilization, and quotients.
| Blood Flow (Doppler Ultrasound) | |
|---|---|
| Pulsatility index | (PSV–EDV)/Timed-average mean velocity (TAMV) |
| Resistance index | (PSV-EDV)/PSV |
| Umbilical Blood Flow (mL/min) | TAMV × (π/4) × Artery cross-sectional area × 60 |
| Blood Flow (3H2O Tracer) | |
| Rinf 3H2O (dpm/min) | Pump rate × [infusate] |
| Racc(f) (dpm/min) | αpl slope × (0.8 × fetal weight) |
| Racc(m) (dpm/min) | Racc(f) + [αpl slope × 0.8(uterine weight)] |
| Umbilical Blood Flow (UBF; mL/min) | (Rinf − Racc(f))/([3H2O]α(WB) − [3H2O]γ(WB)) |
| Umbilical Plasma Flow (UPF; mL/min) | UBF × [1 − Hctf(avg)] |
| Uterine Blood Flow (UtBF; mL/min) | (Rinf − Racc(m))/([3H2O]V(WB) − [3H2O]A(WB)) |
| Uterine Plasma Flow (UtPF; mL/min) | UtBF × [1 − Hctm(avg)] |
| Nutrient Uptake and Utilization Rates | |
| Umbilical Oxygen Uptake (UOU; mmol/min) | UBF × ([O2]γ(WB) − [O2]α(WB)) |
| Uterine Oxygen Uptake (UtOU; mmol/min) | UtBF × ([O2]A(WB) − [O2]V(WB)) |
| Uteroplacental Oxygen Utilization (mmol/min) | UtOU − UOU |
| Plasma to WB Glucose Conversion | [G]pl × [1 − (0.24 × Hct)] − (3.3 × Hct) |
| Umbilical Glucose Uptake (UGU; µmol/min) | UBF × ([G]γ(WB) − [G]α(WB)) |
| Uterine Glucose Uptake (UtGU; µmol/min) | UtBF × ([G]A(WB) − [G]V(WB)) |
| Uteroplacental Glucose Utilization (µmol/min) | UtGU − UGU |
| Umbilical Lactate Uptake (µmol/min; ULU) | UBF × ([L]γ(pl) − [L]α(pl)) |
| Uterine Lactate Secretion (µmol/min; UtLS) | UtBF × ([L]V(pl) − [L]A(pl)) |
| Uteroplacental Lactate Production (µmol/min) | ULU + UtLS |
| Umbilical AA Uptake (µmol/min; UAAU) | UPF × ([AA]γ(pl) − [AA]α(pl)) |
| Uterine AA Uptake (µmol/min; UtAAU) | UtPF × ([AA]A(pl) − [AA]V(pl)) |
| Umbilical AA Carbon Uptake (µmol/min; UCU) | (#AA carbons) × UAAU |
| Uterine AA Carbon Uptake (µmol/min; UtCU) | (#AA carbons) × UtAAU |
| Umbilical AA Nitrogen Uptake (µmol/min; UNU) | (#AA nitrogens) × UAAU |
| Uterine AA Nitrogen Uptake (µmol/min; (UtNU) | (#AA nitrogens) × UtAAU |
| Fetal Nutrient: Oxygen Quotients | |
| Glucose:Oxygen (G:O) quotient | 6 × ([G]γ(WB) − [G]α(WB))/([O2]γ(WB) − [O2]α(WB)) |
| Lactate:Oxygen (L:O) quotient | 3 × ([L]γ(pl) − [L]α(pl))/([O2]γ(WB) − [O2]α(WB)) |
| Amino Acid:Oxygen (AA:O) quotient | Q × ([AA]γ(pl) − [AA]α(pl))/([O2]γ(WB) − [O2]α(WB)) |
| Total Nutrient:Oxygen quotient | G:O quotient + L:O quotient + Total AA:O quotient |
1 Calculations are derived from Cilvik et al., 2021.