الفهرس 
Doppler effectOnly 14 pages are availabe for public view
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Abstract
Transoesophageal echocardiography (TOE) has been applied widely in ventilated patients with haemodynamic instability. For more than 25 years, pulmonary artery catheterisation has been the clinical
standard in the management of the haemodynamically unstable patient
and, in particular, for determining cardiac output. However, both
methodological and patient-related theoretical and practical problems
have been described with respect to estimation of cardiac output by
the thermodilution technique. In mechanically ventilated patients, left
ventricular compliance may vary significantly throughout the
ventilatory cycle. The consequence is a simultaneously changing left
ventricular preload, resulting in a condition of nonconstant blood flow
during the thermodilution cardiac output measurement.
The current study was designed to evaluate the feasibility and
accuracy of determining Doppler cardiac output at the level of the
LVOT using either pulsed- or continuous-wave Doppler in both a
transverse and longitudinal plane. The Doppler data were obtained in
various haemo-dynamically different situations in the peri-operative
setting of coronary artery bypass surgery and compared with
thermodilution cardiac output measurements.
Summary and conclusion
Discussion
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(138)
The study was done at National Heart Institute during the period
from December 2001 to April 2002. The patients were thirty in
number, they suffered from ischemic heart disease as designated by
symptoms, ECG and thallium scanning and documented by coronary
angiography.
The current study primarily demonstrated that cardiac output data,
estimated either with pulsed- or continuous-wave Doppler of the
LVOT, obtained from a deep transgastric view, correlate well with
those derived from thermodilution cardiac output. Repeated
measurements: immediately post-induction of anesthesia, 20-minutes
after cardio-pulmonary bypass and 1 hour postoperatively showed
almost the same strong positive correlation between the two methods.
In conclusion, this study demonstrates the feasibility of measuring
cardiac output reliably and offers a valuable alternative to the
thermodilution technique, in particular in view of the additional value
of TOE. Either pulsed- or continuous-wave Doppler can be used to
measure cardiac output in patients after cardiac surgery without
tricuspid regurgitation or aortic valvular pathology from a deep transgastric image in a transverse plane with a low failure rate.