Peripheral oxygenation and management in the perinatal period

The mechanisms for the adequate provision of oxygen to the peripheral tissues are complex. They involve control of the microcirculation and peripheral blood flow, the position of the oxygen dissociation curve including the proportion of fetal and adult haemoglobin, blood gases and viscosity. Systemic blood pressure appears to have little effect, at least in the non-shocked state. The adequate delivery of oxygen (DO2) depends on consumption (VO2), which is variable. The balance between VO2 and DO2 is given by fractional oxygen extraction (FOE=VO2/DO2). FOE varies from organ to organ and with levels of activity. Measurements of FOE for the whole body produce a range of about 0.15–0.33, i.e. the body consumes 15–33% of oxygen transported.