foetal circulation
Before birth
Umbilical vessels
Umbilical vein x 1
Umbilical arteries x 2
Uterine flow = 600mL/min
Maternal [Hb] = 120g/L
p50 = 26.6mmHg
NB:
Uterine blood flow = 500-750mL/min
85% of uterine blood flow goes to placenta
Umbilical flow = 300mL/min
Foetal [Hb] = 170g/L
p50 = 18-20mmHg
pO2 = 18mmHg
pO2 = 28mmHg
=====
[KB2:p251]
Respiratory parameters: Neonate vs adult
Neonate | Adult | units | |
Dead space | 2.2 | 2.2 | mL/kg |
Tidal volume | 7 | 7 | mL/kg |
Vd/Vt | 0.3 | 0.3 | mL/kg |
Alveolar ventilation | 120-140 | 60-70 | mL/kg/min |
RR | 30-40 | 10-15 | breath/min |
I:E | 1 | 1.5 | |
FRC | 30 | 30 | mL/kg |
Specific compliance | 0.05 | 0.05 | /cmH2O |
Oxygen consumption | 6-7 | 3-3.5 | mL/kg/min |
NB: Foetal oxygen consumption at term = 5 mL/kg/min
=====
[KB2:p6]
During pregnancy,
Blood volume increase by 40 to 45% by term
Plasma volume increase by 50% by term
--> Hemodilution
--> Physiological anaemia of pregnancy
NB: