What Should We Do about Low Blood Pressure in Preterm Infants

The management of preterm infants with low blood pressure soon after birth remains unresolved. The definition of what constitutes low blood pressure is uncertain. At birth, mean blood pressure appears to be gestation specific and increases in the first few days of life. Antenatal steroids, delayed cord clamping, and the avoidance of mechanical ventilation are all associated with higher mean blood pressure and less hypotension after birth. Rates of hypotension of 15-50% have been reported in various studies of extremely preterm infants. However, only about 10% of all extremely preterm infants receive inotropes, suggesting that clinicians take into account other factors such as clinical, biochemical, and echocardiographic findings before deciding to intervene. The exact role of functional echocardiography in assessing the need for treatment of low blood pressure in extremely preterm infants remains to be determined. Near- infrared spectroscopy to assess cerebral perfusion may also have a role to play. Volume expansion (usually 10 mL/kg of saline) remains the most commonly used intervention for low blood pressure but evidence of benefit is lacking and there may be safety concerns. Whilst dopamine is the most commonly used inotropic drug, dobutamine, epinephrine, corticosteroids, milrinone, and vasopressin have also been utilised in preterm infants with low blood pressure. Clinical trials with long-term outcomes are needed to determine the most suitable inotrope and when to use it. Early hypotension differs from late hypotension with regard to cause, treatment, and outcome. A number of recent studies aimed at improving the evidence base for the treatment of early hypotension in extremely preterm infants have been terminated early because of poor recruitment. Currently, the answer to the question of what to do about low blood pressure in preterm infants remains unclear.