Preload indexes in thoracic anesthesia

Perioperative Pulse Contour Cardiac Output Analysis in a Patient with Severe Cardiac Dysfunction

We describe a patient with severe left ventricular dysfunction simultaneously monitored with pulse contour cardiac output (PiCCO) analysis, a continuous cardiac output pulmonary artery catheter (continuous COPAC) and intraoperative transoesophageal echocardiography (TOE).

There was good agreement between cardiac output (CO) measurements obtained by the three techniques prior to cardiopulmonary bypass (CPB). Agreement of CO measurements following CPB was initially poor, but improved following recalibration of PiCCO.

PiCCO-derived global end-diastolic volume index (GEDVI) and cardiac function index (CFI), were assessed as markers of left ventricular preload and myocardial contractility, respectively. GEDVI correlated well with CO in the postoperative period.

CFI increased more than two -fold following coronary revascularization and milrinone administration, and there was also a temporal relationship between the CFI and the dose of milrinone in the first 24 hours of treatment.

Global end-diastolic volume and cardiac function index may be useful additional measures of left ventricular preload and myocardial contractility in patients with severe left ventricular dysfunction.

Stroke volume variation fail to predict fluid responsiveness in patients undergoing pulmonary lobectomy with one-lung ventilation using thoracotomy

The purpose of this study was to investigate the ability of stroke volume variation (SVV) to predict fluid responsiveness in patients undergoing pulmonary lobectomy with one lung ventilation (OLV). Thirty patients intubated with double-lumen tube were scheduled for a pulmonary lobectomy requiring OLV for at least 1 hour under general anesthesia. Hemodynamic variables including heart rate, mean arterial pressure, cardiac index (CI), stroke volume index (SVI), central venous pressure (CVP) and SVV were measured before and after volume expansion (VE) (8 mL/kg of 6% hydroxyethyl starch). Fluid responsiveness was defined as an increase in CI ≥ 10% after VE. Of the 30 patients, 16 (53%) were responders and 14 (47%) were nonresponders to intravascular VE. There were significant increases of CI, SVI in responders after VE (p < 0.01), but there were no significant changes in SVV in responders and nonresponders (p > 0.05). The baseline value of SVV, CVP, CI and SVI did not correlate significantly with ΔCI (p > 0.05). The area under the Receiver Operating Characteristic (ROC) curve were 0.507 for SVV (95% confidence interval, 0.294-0.720) and 0.556 for CVP (95% confidence interval, 0.339-0.773), neither was able to predict fluid responsiveness with sufficient statistical power. SVV measured by the Vigileo-FloTrac system was not able to predict fluid responsiveness in patients undergoing pulmonary lobectomy with OLV after thoractomy.

Pulse pressure variation as a predictor of fluid responsiveness during one-lung ventilation for lung surgery using thoracotomy: randomised controlled study

BACKGROUND AND OBJECTIVE

Pulse pressure variation (PPV) is increasingly advocated as a predictor of fluid responsiveness in patients receiving mechanical ventilation. However, the ability of PPV has never been studied during one-lung ventilation (OLV). Therefore, we evaluated the value of PPV to predict fluid responsiveness in patients receiving conventional and protective OLV using receiver operating characteristic (ROC) analysis, respectively.

METHODS

Forty-nine patients undergoing lung surgery requiring OLV were enrolled in this study. Patients were randomised either to group P [patients receiving protective OLV with tidal volume 6 ml kg, inspired oxygen fraction (FIO2) of 0.5 and positive end-expiratory pressure (PEEP) of 5 cmH2O) or group C (patients receiving conventional OLV with tidal volume of 10 ml kg, FIO2 of 1.0 and no PEEP). Following OLV, PPV and cardiac output were measured before and 12 min after fluid loading (7 ml kg hydroxyethyl starch 6%). Patients whose cardiac indices increased by at least 15% to fluid loading were defined as the responders.

RESULTS

The areas under ROC curve for PPV were 0.857 (P = 0.006) in group P and 0.524 (P = 0.839) in group C, respectively. The optimal threshold value given by ROC analysis for PPV was 5.8% in group P.

CONCLUSIONS

PPV could predict fluid responsiveness only during protective OLV, but not conventional OLV. PPV would be helpful for fluid management in patients receiving protective OLV for lung surgery using thoracotomy.