"Aggressive shock therapy": a relic?

Ohne Zusammenfassung Prof. Dr. W.F. Dick Klinik für Anaesthesiologie des Klinikums der Universit?t Mainz, Langenbeckstra?e 1, 55131 Mainz, E-mail: dick@anaesthesie.klinik.uni-mainz.de     

What constitutes a "high-volume" hospital for pancreatic resection?

BACKGROUND: Annual institution resection volume has been proposed for defining centers of excellence, with various cut-offs for defining "high-volume" centers used. This study aimed to define an objective, evidence-based operative volume threshold associated with improved postoperative outcomes after pancreatic resection. STUDY DESIGN: This retrospective analysis of patients who underwent pancreatic resection in the Nationwide Inpatient Sample, a 20% representative sample of patients in the US between 1998 and 2003, was performed using multivariable logistic regression. Different models of annual hospital resection volume were analyzed and the goodness of fit of each "high-volume" model to postoperative mortality was compared through use of the pseudo r(2). RESULTS: Based on analysis of 7,558 patients who underwent pancreatic resection, median annual institution resection volume was 15 (range 1 to 254), and overall in-hospital mortality was 7.6%. The best model of "high-volume" centers was an annual institution resection volume of 19 or more, as determined by goodness of fit (r(2) of 5.29%). But there was little difference in data variance explained between this best model and other "high-volume" models. The model without any volume variable had a goodness-of-fit r(2) of 3.57%, suggesting that volume explains less than 2% of data variance in perioperative death after pancreatic resection. CONCLUSIONS: Very little difference was observed in the explanatory powers of models of "high-volume" centers. Although volume has an important impact on mortality, volume cut-off is necessary but insufficient for defining centers of excellence. Volume appears to function as an imperfect surrogate for other variables, which may better define centers of excellence.     

Minimal change disease: a "two-hit" podocyte immune disorder?

Minimal change disease (MCD) is the most common nephrotic syndrome in children and is commonly thought to be a T-cell disorder mediated by a circulating factor that alters podocyte function resulting in massive proteinuria. We suggest that MCD is a “two-hit” disorder. As originally hypothesized by Reiser et al. in 2004, we propose that the initial hit is the induction of CD80 (also known as B7.1) on the podocyte, and that this results in an alteration in shape with actin rearrangement that alters glomerular permeability and causes proteinuria. We propose that CD80 expression may result from either direct binding of the podocyte by cytokines from activated T cells or by activation of podocyte toll-like receptors (TLR) by viral products or allergens. We further hypothesize that under normal circumstances, CD80 expression is only transiently expressed and proteinuria is minimal due to rapid autoregulatory response by circulating T regulatory cells or by the podocyte itself, probably due to the expression of factors [cytotoxic T-lymphocyte-associated (CTLA)-4, interleukin (IL)-10, and possibly transforming growth factor (TGF)-β] that downregulate the podocyte CD80 response. In MCD, however, there is a defect in CD80 podocyte autoregulation. This results in persistent CD80 expression and persistent proteinuria. If correct, this hypothesis may lead to both new diagnostic tests and potential therapeutics for this important renal disease.     

Is there a "learning curve" for muscle perforator flaps?

Although soft tissue free flaps have been in the mainstream for over 40 years, muscle perforator flaps per se are a relatively recent addition to the armamentarium of the reconstructive microvascular surgeon. Even though actually only a fasciocutaneous flap subtype, a distinctively different approach is necessary for their safe and reliable use, which has deterred many from adopting this valuable asset for fear of not being able to master an implied "learning curve." Whether this is a justifiable excuse led to our examination of our original microsurgical experience from 1982-1986, which in retrospect had its own learning curve. All 30 soft tissue flaps during that initiation period were muscle free flaps, which not only had a now unacceptable 37% major complication rate but also a complete failure rate of 26% due specifically to our technical inadequacies with the requisite microanastomoses. When compared with our first 30 muscle perforator flaps, there was a similar incidence of major complications (30%), although the eventual transferred flap success rate was 97%. This confirmed the existence of a learning curve in our preliminary experience with muscle perforator flaps that was consistent with any surgical innovation. However, our microsurgical prowess by this time had facilitated the acquisition of the skills to comfortably harvest a muscle perforator flap with a very acceptable success rate that minimized the steepness of our particular learning curve. Just what will be the configuration of the unavoidable muscle perforator flap learning curve specific for each individual will depend on their own capabilities, the relative technical difficulty of a given flap, and the level of competency expected.