Cardiac function and morphology studied by two‐dimensional doppler echocardiography in unsedated newborn pigs

Abstract

S U M M A R YThe newborn pig is currently the most used species in animal neonatal research. Valid noninvasive monitoring is important in particular for long-term survival of unsedated aniimals. In the unsedated newborn pig ( n = 35, median age 24 h, range 7-48 h) we standairdized twodimensional Doppler echocardiography and determined the normal ranges for cardiac function. Probe positioning had to be adjusted to the V-shaped thorax and the mid-line position of the heart. Six out of the sixteen animals c 20 h had a patent ductus arteriosus compared with one of the twenty animals > 20 h old. One atrial septal defect (5 mm) and one small ventricular septal defect were diagnosed. The average heart size was 0.7-0.9 % of body weight which is similar to human infants of the same size. The mean aortic diameter was 6.0 f 0.5 mm (mean f s.D.) and cardiac output was 0.38 Ifr 0.08 1 min-'; both correlate with body weight (r = 0.80 and 0.73, respectively).Tricuspid regurgitation velocity was 3.0 f 0.4 m s-' (mean f S.D.), giving an estimated pressure gradient across the tricuspid valve of 37 f 9.7 mmHg. The aortic diameter and the heart weight per kg body weight are comparable to those reported for preterm neonates. The cardiac output and velocities across the four valves are more comparable with term neonates.

The use of live three-dimensional Doppler echocardiography in the measurement of cardiac output

“…Cardiac output values in these animals were in the physiological ranges for animals of this size, approximately 100 ml/kg (25,26). In this study, the 3-DE results overestimated the CO by 7.3%.…”

Xenon offers stable haemodynamics independent of induced hypothermia after hypoxia–ischaemia in newborn pigs

“…The neuroprotection effects of the Xe and HT combination from this study have already been published [10]. Here we aimed to determine the effects of Xe and HT on blood pressure, inotropic support and HR after global HI in a newborn pig model, which has cardiovascular physiology [17,18] and haemodynamic responses similar to asphyxiated newborn babies.…”

Cardiac output, pulmonary artery pressure, and patent ductus arteriosus during therapeutic cooling after global hypoxia-ischaemia

“…From the low midcostal long and short axis views and a right sided parasternal long axis view, the cardiac morphology, the occurrence of a PDA, the aortic valve diameter, and the forward peak velocities across the four valves were measured using echocardiographs, Doppler ultrasound, and colour Doppler as previously described. 7 The tricuspid regurgitation (TR) peak velocity signal was manually traced for calculation of the pressure gradient between the right ventricle and right atrium (mm Hg). For this calculation, the in built program in the CFM 750 applies the modified Bernoulli's equation.…”

“…7 The aim of the present study was also to assess by Doppler echocardiography the effects on CO, PAP, and the presence of PDA of 24 hours of mild hypothermia without sedation as compared with normothermia, after a global hypoxicischaemic insult in newborn piglets.…”