Hemodynamic monitoring during cardiac surgery in France: a multicentric prospective study.

Background and Goal of study.
New monitoring systems and inotropic drugs, developed in the past decade, have modified the hemodynamic management during and after cardiac surgery. However, only sparse data are available to reflect these changes and the last national inquiry in France was performed in 2005. This study aimed at giving an up-to-date overview of advanced hemodynamic monitoring in cardiac surgery in France.

Material and Methods.
This national inquiry was proposed to every cardiac surgery center in France. Patient medical history, monitoring characteristics, type and outcomes of surgery were prospectively recorded during 7 weeks for every patients who underwent cardiac surgery in the participating centers. Primary objective was the description of advanced monitoring. Secondary outcome was to assess the influence of monitoring on post-operative outcomes.

Results and Discussion.
During the inclusion period, 3100 patients underwent cardiac surgery in 37 centers. Among them, 1656 (53.4%) beneficiated from advanced hemodynamic monitoring. Cardiac output was monitored by transesophageal echocardiogram (1139, 36.8%), thermodilution (370, 11.9%), pulse contour analysis (32, 1.0%), esophageal Doppler (14, 0.5%) or thoracic impedancemetry (3, 0.1%). Metabolic balance was monitored by ScvO2 (485, 15.7%) or SVO2 (206, 6.6%).
Advanced monitoring was more often used on patients who presented Left-Ventricular Ejection Fraction impairment, pre-operative kidney failure, anemia, and who underwent combined (valvular and coronary) surgery, or in emergency situations. The mean Euroscore II was higher for the monitored patients (4.7 +/- 7.5 vs3.3 +/- 5.2, p<.001).
New inotropic drugs were rarely used (Levosimendan: 8 (0.3%), Milrinone: 22 (0.7%)) compared to dobutamine (422 (13.6%)). 
Finally, monitored patients presented more post-operative complications than the others (63.6% vs 45.1%, p<.001) and a higher mortality (5.1% vs 2.3%, p<.001) as expected by pre-operative Euroscore II. However, in the elderly population (over 80 years old), though monitored patients had more serious preoperative condition (Euroscore II 7.5 +/- 11.8 vs 5.0 +/- 6.1, p<.001), they did not presented more post-operative complications (55.2% vs 48.6 %, p=0.388) nor mortality (6.1% vs 4.4%, p=0.782). 

Conclusions
These findings support the hypothesis that specific subgroups of patients, such as elderly patients, may beneficiate more from advanced monitoring than others.