Perioperative Interstitial Fluid Expansion Predicts Major Morbidity Following Pancreatic Surgery: Appraisal by Bioimpedance Vector Analysis

Objective: To evaluate whether perioperative bioimpedance vector analysis (BIVA) predicts the occurrence of surgery-related morbidity. Summary Background Data: BIVA is a reliable tool to assess hydration status and compartimentalized fluid distribution. Methods: The BIVA of patients undergoing resection for pancreatic malignancies was prospectively measured on the day prior to surgery and on postoperative day (POD)1. Postoperative morbidity was scored per the Clavien-Dindo classification (CDC), and the Comprehensive Complication Index (CCI). Results: Out of 249 patients, the overall and major complication rates were 61% and 16.5% respectively. The median CCI was 24 (IQR 0.0–24.2), and 24 patients (9.6%) had a complication burden with CCI≥40. At baseline the impedance vectors of severe complicated patients were shorter compared to the vectors of uncomplicated patients only for the female subgroup (P=0.016). The preoperative extracellular water (ECW) was significantly higher in patients who experienced severe morbidity according to the CDC or not [19.4L (17.5–22.0) vs. 18.2L (15.6–20.6), P=0.009, respectively] and CCI≥40, or not [20.3L (18.5–22.7) vs. 18.3L (15.6–20.6), P=0.002, respectively]. The hydration index on POD1 was significantly higher in patients who experienced major complications than in uncomplicated patients (P=0.020 and P=0.025 for CDC and CCI, respectively). At a linear regression model, age (β=0.14, P=0.035), sex female (β=0.40, P<0.001), BMI (β=0.30, P<0.001), and malnutrition (β=0.14, P=0.037) were independent predictors of postoperative ECW. Conclusion: The amount of extracellular fluid accumulation predicts major morbidity after pancreatic surgery. Female, obese and malnourished patients were at high risk of extracellular fluid accumulation.