[What's the best assessment of preload after cardiac surgery?]

The assessment of the role of transesophageal echocardiography and invasive tests with pulmonary modified catheter to monitor the preload indexes in patients in intensive-care-unit after cardiac coronary surgery.

Between January and December 2004 24 patients (14 male, 10 female) with coronary artery disease were prospectively enrolled for preload assessment during off-pump myocardial revascularization. Pulmonary Capillary Wedge Pressure (PCWP), Left Ventricular End Diastolic Indexed Area (LVEDAI), delta Aortic Velocity (deltaVAo), Right Ventricular End Diastolic Volume (RVEDVI) as preload indexes were evaluated. Transesophageal echocardiography and pulmonary modified catheter monitoring were performed during the preoperative period at T1 and after fluid infusion (T2). Patients were considered Responders (R) or No Responders (NR) if the Stroke Volume Index increase at T2 was >20% with respect to T1.

Mean T1 PCWP was similar in both groups (12.8+/-2.2 in R vs. 11.4+/-3 mmHg in NR; p=NS) and mean increase of PCWP at T2 was similar in both groups (1.5+/-0.3% in R vs. 1.2+/-3% in NR; p=NS). Mean T1 RVEDVI was similar in both groups (97.33+/-34 in R vs. 101+/-21 ml/m2 in NR; p=NS); T2 RVEDVI was similar in R and NR Groups (122.11+/-49 vs. 138.54+/-30 ml/m2; p=NS); mean T1 and T2 LVEDAI was similar in R and NR (11.2+/-3.5 vs. 10.2+/-2.3 at T1 and 14.04+/-3.35 vs. 14.67+/-2.1 cm2/m2 at T2 respectively; p=NS). Higher mean value of T1 deltaVAo (20+/-7% in R vs. 10+/-2% in NR; p=0.006) were recorded while similar mean value of T2 deltaVAo were observed (11+/-3% in R vs. 5+/-2% in NR; p=0.743). Correlation index between T1 and T2 deltaVAo (R=0.82) in R was significant (p=0.0002), while correlation index between T1 and T2 deltaVAo (R=0.11) in NR was not significant.

Our study showed in patients soon after coronary cardiac surgery deltaVAo is the only predictor of "fluid responsiveness" and of ventricular compliance.