Individualized intraoperative patient optimization using uncalibrated arterial pressure waveform analysis in high-risk patients undergoing major abdominal surgery

Introduction

Established methods to optimize cardiac function and fluid balance based on flow-related variables are invasive or require considerable attentiveness. The purpose of this study was to guide intraoperative fluid and catecholamine therapy in patients with pre-existing cardiac disease undergoing major abdominal surgery using a recently introduced less-invasive device without the need for manual calibration (FloTrac/Vigileo™) and to determine possible improvement in outcome by means of N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels and the duration of hospital stay.

Methods

Forty American Society of Anesthesiologists III patients scheduled for elective major abdominal surgery with pre-existing cardiac disease (coronary artery disease, myocardial infarction, cardiac surgery, heart failure, cardiomyopathy) were studied. Patients were randomly allocated into a standard care group and an intervention group, where a stroke volume variation (SVV) and cardiac index (CI)-based protocol for volume and catecholamine therapy was implemented until the end of surgery. In brief, CI ≥ 2.5 l/min/m² was aimed for, with a SVV threshold value for fluid challenge of 12%. After the baseline (skin incision), haemodynamic data and plasma NT-proBNP levels were obtained after 180 minutes, at the end of surgery, 5 hours post surgery, and on postoperative days 1 and 2, and the ICU and hospital stays were recorded.

Results

Demographic data and Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity physiology and operation score values were comparable between the groups. The intervention group received significantly more colloid volume replacement and more dobutamine; crystalloid volume replacement and norepinephrine consumption did not differ. Plasma NT-proBNP levels were significantly higher in the standard care group on postoperative days 1 and 2 (832 ± 675 vs. 1,633 ± 690 pg/ml and 1,097 ± 827 vs. 2,085 ± 871 pg/ml). The mean hospital stay was reduced in the intervention group (14.8 ± 4.7 days) versus 20.6 ± 8.1 days in the standard care group (P = 0.009), whereas the ICU stay did not differ significantly.

Conclusion

The use of uncalibrated arterial waveform analysis (FloTrac/Vigileo™) for intraoperative patient optimization in patients with pre-existing cardiac disease undergoing major abdominal surgery is associated with a reduction of hospital stay and lower plasma NT-proBNP levels.