Postnatal development of cardiac distribution in the pig

Area of Science:

• Physiology
• Neonatal Circulation

Background:

• Cardiac output distribution undergoes significant changes during the neonatal period.
• Understanding these shifts is crucial for assessing physiological development in newborn animals.

Purpose of the Study:

• To investigate the changes in cardiac output distribution in piglets at birth (0 hours) and after 12 hours of age, including suckling.
• To compare the blood flow allocation to various organs between neonatal piglets and those that have suckled.

Main Methods:

• Utilized 103Ruthenium-labelled microspheres (15 +/- 3 micrometer diameter) to measure cardiac output distribution.
• Compared measurements in 0-hour-old piglets versus 12-hour-old piglets that had suckled.

Main Results:

• Coronary and bronchial fractions of cardiac output were high at birth.
• Bronchial fraction significantly decreased (p < 0.05) by 12 hours, while coronary fraction remained high.
• Cardiac output to the liver, upper gastrointestinal tract, pancreas, and salivary gland significantly increased (p < 0.01) by 138%, 156%, 85%, and 109% respectively, in 12-hour-old piglets.
• Preferential blood flow shifted from lungs, adrenals, heart, thyroid, and spleen at 0h to adrenals, thyroid, heart, lungs, and diaphragm at 12h.

Conclusions:

• Neonatal piglets exhibit distinct cardiac output distribution patterns at birth.
• Suckling and 12 hours of postnatal life induce significant alterations in blood flow, favoring splanchnic circulation and specific organs like the diaphragm.