Diagnostic ultrasound ( PDFDrive )

CHAPTER 46 Duplex Sonography of the Neonatal and Infant Brain 1579
A
B
FIG. 46.5 High-Frequency Ventilation of Premature Infants. Pulsed wave Doppler tracing shows ventilation-related oscillations next to the
arterial low (A) and venous low (B).
.08
PW PWR <100
30dB 0/–/D
7.0mm/1
PW D= 64mm>
.08
.40
m/s
.20
A
B
FIG. 46.6 Doppler Changes During Extracorporeal Membrane Oxygenation (ECMO). (A) Continuous nonpulsatile low on pulsed wave
Doppler tracing from the anterior cerebral artery in an infant with congenital heart disease and severe cardiac dysfunction during venoatrial ECMO
shows absent arterial pulsatility. (B) In a different infant, residual pulsatile low on pulsed wave Doppler tracing from the anterior cerebral artery in
an infant with congenital heart disease and moderate cardiac dysfunction during venovenous ECMO shows minimal arterial pulsatility.
disappear altogether, especially in association with severe cardiac
dysfunction. 30 Venous drainage and low are typically also afected,
partially as a result of the jugular vein ligation. 27,31
More recently, double-lumen venous cannulas have allowed
the use of venovenous circuits (venovenous extracorporeal
membrane oxygenation [VV-ECMO]) in which the functionally
intact let side of the heart pumps the oxygenated blood (delivered
to the right side of the heart by the VV-ECMO circuit) into the
systemic circulation. Major diferences between the VV-ECMO
circuit and the VA-ECMO circuit are the maintenance of pulsatile
blood low (see Fig. 46.6B), avoidance of ligation of the carotid
artery, and perfusion of the pulmonary and coronary circulation
by well-oxygenated blood. 32 VV-ECMO is used when there is
only pulmonary dysfunction.