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OBJECTIVE: To measure and define the best achievable outcome after major hepatectomy. BACKGROUND: No reference values are available on outcomes after major hepatectomies. Analysis in living liver donors, with safety as the highest priority, offers the opportunity to define outcome benchmarks as the best possible results. METHODS: Outcome analyses of 5202 hemi-hepatectomies from living donors (LDs) from 12 high-volume centers worldwide were performed for a 10-year period. Endpoints, calculated at discharge, 3 and 6 months postoperatively, included postoperative morbidity measured by the Clavien-Dindo classification, the Comprehensive Complication Index (CCI), and liver failure according to different definitions. Benchmark values were defined as the 75th percentile of median morbidity values to represent the best achievable results at 3 month postoperatively. RESULTS: Patients were young (34 ± [9] years), predominantly male (65%) and healthy. Surgery lasted 7 ± [2] hours; 2% needed blood transfusions. Mean hospital stay was 11.7± [5] days. 12% of patients developed at least 1 complication, of which 3.8% were major events (≥grade III, including 1 death), mostly related to biliary/bleeding events, and were twice higher after right hepatectomy. The incidence of postoperative liver failure was low. Within 3-month follow-up, benchmark values for overall complication were ≤31 %, for minor/major complications ≤23% and ≤9%, respectively, and a CCI ≤33 in LDs with complications. Centers having performed ≥100 hepatectomies had significantly lower rates for overall (10.2% vs 35.9%, P < 0.001) and major (3% vs 12.1%, P < 0.001) complications and overall CCI (2.1 vs 8.5, P < 0.001). CONCLUSIONS: The thorough outcome analysis of healthy LDs may serve as a reference for evaluating surgical performance in patients undergoing major liver resection across centers and different patient populations. Further benchmark studies are needed to develop risk-adjusted comparisons of surgical out

This research presents seven different control strategies for an inverter-based compensator used to achieve fast-acting reactive current compensation. Two feedforward schemes and five feedforward/feedback structures are analyzed. The first feedforward configuration uses phase-shift control (or simply [delta]-control) and results from shifting the fundamental component of a fixed pulse-width square wave an angle 8 with respect to the sinusoidal network voltage. The second feedforward scheme uses phase-shift/pulse-width control (or simply [delta]/[mu]-control) and allows, in addition to the phase-shift, a variation of the pulse-width parameterized by [mu]. One feedforward/feedback scheme uses phase-shift control and the remaining feedforward/feedback schemes use phase-shift/pulse-width control. A linearized average model that only considers the fundamental components of the circuit variables, and an exact model that takes into account all the non-linearities of the system are developed. The former model is suitable for control synthesis and stability analysis while the latter is used to benchmark the average model and to evaluate the effect of neglecting the higher-order harmonics. All the control structures are examined in dynamic conditions by analyzing the transition from a capacitive to inductive mode of compensation, and vice-versa. The feedforward structures are also evaluated under stationary conditions in inductive and capacitive compensation modes. The performance achieved by each control strategy is evaluated by examining the compensator's dynamic response, using performance measures. The simulation results indicate that the variation of the pulse-width enables keeping a constant link voltage, and that the best performance is achieved with the [delta]/[mu] feedforward/Is-feedback to [delta] control.