الفهرس | Only 14 pages are availabe for public view |
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 ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ (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. |