The role of peri-hepatic drain placement in liver surgery: a prospective analysis

AbstractBackgroundThe standard use of an intra-operative perihepatic drain (IPD) in liver surgery is controversial and mainly supported by retrospective data. The aim of this study was to evaluate the role of IPD in liver surgery.MethodsAll patients included in a previous, randomized trial were analysed to determine the association between IPD placement, post-operative complications (PC) and treatment. A multivariate analysis identified predictive factors of PC.ResultsOne hundred and ninety-nine patients were included in the final analysis of which 114 (57%) had colorectal liver metastases. IPD (n = 87, 44%) was associated with pre-operative biliary instrumentation (P = 0.023), intra-operative bleeding (P < 0.011), Pringle's manoeuver(P < 0.001) and extent of resection (P = 0.001). Seventy-seven (39%) patients had a PC, which was associated with pre-operative biliary instrumentation (P = 0.048), extent of resection (P = 0.002) and a blood transfusion (P = 0.001). Patients with IPD had a higher rate of high-grade PC (25% versus 12%, P = 0.008). Nineteen patients (9.5%) developed a post-operative collection [IPD (n = 10, 11.5%) vs. no drains (n = 9, 8%), P = 0.470]. Seven (8%) patients treated with and 9(8%) without a IPD needed a second drain after surgery, P = 1. Resection of ≥3 segments was the only independent factor associated with PC [odds ratio (OR) = 2, P = 0.025, 95% confidence interval (CI) 1.1–3.7].DiscussionIn spite of preferential IPD use in patients with more complex tumours/resections, IPD did not decrease the rate of PC, collections and the need for a percutaneous post-operative drain. IPD should be reserved for exceptional circumstances in liver surgery

Empirical Phi-Discrepancies and Quasi-Empirical Likelihood: Exponential Bounds

We review some recent extensions of the so-called generalized empirical likelihood method, when the Kullback distance is replaced by some general convex divergence. We propose to use, instead of empirical likelihood, some regularized form or quasi-empirical likelihood method, corresponding to a convex combination of Kullback and χ2 discrepancies. We show that for some adequate choice of the weight in this combination, the corresponding quasi-empirical likelihood is Bartlett-correctable. We also establish some non-asymptotic exponential bounds for the confidence regions obtained by using this method. These bounds are derived via bounds for self-normalized sums in the multivariate case obtained in a previous work by the authors. We also show that this kind of results may be extended to process valued infinite dimensional parameters. In this case some known results about self-normalized processes may be used to control the behavior of generalized empirical likelihood