The Validation of Cardiac Index and Stroke-Volume Variation Measured by the Pulse-Wave Transit Time-Analysis Versus Conventional Pulse-Contour Analysis After Off-Pump Coronary Artery Bypass Grafting: Observational Study.

OBJECTIVE: To compare the reliability of cardiac index (CI) and stroke-volume variation (SVV) measured by the pulse-wave transit-time (PWTT) method using estimated continuous cardiac output (esCCO) technique with conventional pulse-contour analysis after off-pump coronary artery bypass grafting (OPCAB). DESIGN: A single-center, prospective, observational study. SETTING: At a 1,000-bed university hospital. PARTICIPANTS: A total of 21 patients were enrolled after elective OPCAB. INTERVENTIONS: The study authors performed a method comparison study with simultaneous measurement of CI and SVV based on the esCCO technique (CIesCCO and esSVV, correspondingly) and pulse-contour analysis (CIPCA and SVVPCA, correspondingly). As a secondary analysis, they also assessed the trending ability of CIesCCO versus CIPCA. MEASUREMENTS AND MAIN RESULTS: The authors analyzed 178 measurement pairs for CI, and 174 pairs for SVV during the 10 study stages. The mean bias between CIesCCO and CIPCA was 0.06 L min/m2, with limits of agreement of ± 0.92 L min/m2 and a percentage error (PE) of 35.3%. The analysis of the trending ability of CI measured by PWTT revealed a concordance rate of 70%. The mean bias between esSVV and SVVPCA was -6.1%, with limits of agreement of ± 15.5% and a PE of 137%. CONCLUSIONS: The overall performance of CIesCCO and esSVV versus CIPCA and SVVPCA is not clinically acceptable. A further improvement of the PWTT algorithm may be required for an accurate and precise assessment of CI and SVV.

Continuous Monitoring of Lactate Using Intravascular Microdialysis in High-Risk Cardiac Surgery: A Prospective Observational Study.

OBJECTIVE: To assess the accuracy and applicability of a novel system, not requiring calibration, for continuous lactate monitoring with intravascular microdialysis in high-risk cardiac surgery. DESIGN: Single-center prospective observational study. SETTING: City Hospital #1 of Arkhangelsk, Russian Federation. PARTICIPANTS: Twenty-one adult patients undergoing elective complex repair or replacement of two or more valves or combined valve and coronary artery cardiac surgery. INTERVENTIONS: After induction of anesthesia, in all patients a dedicated triple-lumen catheter functioning as a regular central venous catheter with integrated microdialysis function was inserted via the right jugular vein for continuous lactate monitoring using the intravascular microdialysis system. MEASUREMENTS AND MAIN RESULTS: Lactate values displayed by the microdialysis system were compared with the reference arterial blood gas (ABG) values. In total, 432 paired microdialysis-ABG lactate samples were obtained. After surgery, the concentration of lactate increased significantly, peaking at 8 hours (p<0.05). The lactate clearance within 8 hours after peak concentration was 50% (39%-63%). There was a significant correlation between Lactatecont and Lactatecont (rho = 0.92, p<0.0001). Bland-Altman analysis showed a bias (mean difference)±limits of agreement (±1.96 SD) of 0.09±1.1 mmol/L. In patients with postoperative complications, peak lactate concentration was significantly higher compared with those without complications: 6.75 (4.43-7.75) mmol/L, versus 4.20 (3.95-4.87) mmol/L (p = 0.002). CONCLUSIONS: Lactate concentration increased significantly after high-risk cardiac surgery. The intravascular microdialysis technique for lactate measurement provided acceptable accuracy and can be used for continuous blood lactate monitoring in cardiac surgery.

Comparison of goal-directed hemodynamic optimization using pulmonary artery catheter and transpulmonary thermodilution in combined valve repair: a randomized clinical trial.

Our aim was to compare the effects of goal-directed therapy guided either by pulmonary artery catheter (PAC) or by transpulmonary thermodilution (TTD) combined with monitoring of oxygen transport on perioperative hemodynamics and outcome after complex elective valve surgery. Measurements and Main Results. Forty patients were randomized into two equal groups: a PAC group and a TTD group. In the PAC group, therapy was guided by mean arterial pressure (MAP), cardiac index (CI) and pulmonary artery occlusion pressure (PAOP), whereas in the TTD group we additionally used global end-diastolic volume index (GEDVI), extravascular lung water index (EVLWI), and oxygen delivery index (DO(2)I). We observed a gradual increase in GEDVI, whereas EVLWI and PAOP decreased by 20-30% postoperatively (P < 0.05). The TTD group received 20% more fluid accompanied by increased stroke volume index and DO(2)I by 15-20% compared to the PAC group (P < 0.05). Duration of mechanical ventilation was increased by 5.2 hrs in the PAC group (P = 0.04). Conclusions. As compared to the PAC-guided algorithm, goal-directed therapy based on transpulmonary thermodilution and oxygen transport increases the volume of fluid therapy, improves hemodynamics and DO(2)I, and reduces the duration of respiratory support after complex valve surgery.