Reimer P, et al. - The primary aim of this study is to assess the predictive value of heart-rate variability (HRV) concerning the development of postoperative complications in patients undergoing major abdominal surgery (MAS). The secondary goals are to recognize the relationship of HRV and utilization of vasoactive drugs amid anesthesia, intensive care unit length of stay (ICU-LOS), and hospital length of stay (H-LOS). Preoperative HRV assessment amid orthostatic load is objective and valuable for identifying patients with low autonomic physiological reserves and high risk of poor post­operative course.

Methods

• For this research, they designed a prospective, single-center, observational study.
• Total 65 patients scheduled for elective MAS were enrolled in this study.
• HRV was measured by spectral analysis (SA) preoperatively amid orthostatic load.
• They divided patients according to cardiac autonomic reactivity (CAR; n=23) and non-cardiac autonomic reactivity (NCAR; n=30).

Results

• Total 53 patients were included in the final analysis.
• There was no significant difference between the two groups regarding type of surgery, utilization of minimally invasive techniques or epidural catheter, duration of surgery and anesthesia, or the amount of fluid administered intraoperatively.
• The NCAR group had significantly greater intraoperative blood loss than the CAR group (541.7±541.9 mL vs 269.6±174.3 mL, p<0.05).
• In the NCAR group, vasoactive drugs were utilized amid anesthesia more frequently (n=21 vs n=4; p<0.001), and more patients had at least one postoperative complication compared to the CAR group (n=19 vs n=4; p<0.01).
• Besides, the NCAR group had more serious complications (Clavien–Dindo ≥ Grade III n=6 vs n=0; p<0.05) and a greater number of complications than the CAR group (n=57 vs n=5; p<0.001).
• Significant differences were found for two specific subgroups of complications: hypotension requiring vasoactive drugs (NCAR: n=10 vs CAR: n=0; p<0.01) and ileus (NCAR: n=11 vs CAR: n=2; p<0.05).
• Moreover, important differences were seen in the ICU-LOS (NCAR: 5.7±3.5 days vs CAR: 2.6±0.7 days; p<0.0001) and H-LOS (NCAR: 12.2±5.6 days vs CAR: 7.2±1.7 days; p<0.0001).