[PULSE WAVE TRANSIT TIME - ONE MORE ATTEMPT OF NON-INVASIVE CARDIAC OUTPUT MEASUREMENT.]

Background: Estimated continuous cardiac output (esCCOTM) based on pulse wave transit time is one of alternative non-invasive CO measurement techniques.

Methods: Randomized study included 23 scheduled patients operated upon due to cardiovascular diseases. Cardiac index (CI) was measured Comparative analyses of esCCO and others CO measurement methods used intraoperative was carried out. In the first group (n = 9) esCCO was compared with transpulmonary thermodilution (PiCCO-plus); in the second group (n = 8) - with pulmonary artery thermodilution; in the third group (n = 6) - with transoesophageal echocardiography (velocity-time integral).

Results: In the 1st group direct correlation was found (r = 0,773, p <0.0001), but overestimation was found in 39% of cases; underestimation in 4%. The 2nd group showed direct correlation (r = 0.586, p <0.0001). The 3d group showed direct relationship (r = 0.68, p = 0.0018), but 66.7% of the measurements were out of reference interval (more than ? 15%). Blend- Altman method showed the dispersion of results in all groups.

Conclusions: 1. Estimated continuous cardiac output measurement technique based on PWTT has a direct correla- tion with prepulmonary thermodilution and transoesophageal echocardiography, medium and high power respectively. 2. esCCO has significant differences with the referential techniques during general anesthesia in cardiac surgery pa- tients. 3. Calibration based on invasive blood pressure and outside cardiac output measurement does not increase the accuracy of measurements. 4. esCCO has a negative diagnostic value and cannot be recommendedfor the cardiac out- put evaluation during cardiac surgery. 5. This method can be useful for analyze general effectiveness of perioperative hemodynamics.