Journal article

Characteristics and physiological basis of falls in ventricular outputs after immediate cord clamping at delivery in preterm fetal lambs.

Joseph J Smolich, Kelly R Kenna, Sarah E Phillips, Jonathan P Mynard, Michael MM Cheung, Gavin W Lambert

The Journal of Physiology | Wiley | Published : 2021

Abstract

KEY POINTS: Controversy exists about the physiological mechanism(s) underlying decreases in cardiac output after immediate clamping of the umbilical cord at birth To define these mechanisms, the four major determinants of ventricular output (afterload, preload, heart rate and contractility) were measured concurrently in fetal lambs at 15s intervals over a 2-minute period after cord clamping and before ventilation following delivery After cord clamping, right (but not left) ventricular output fell by 20% in the initial 30s, due to increased afterload associated with higher arterial blood pressures, but both outputs then halved over 45s, due to a falling heart rate and deteriorating ventricula..

View full abstract