Strain induced esophageal growth in a novel rodent model.

PURPOSE: Longitudinal esophageal strain has been shown to increase esophageal length but the contribution of tissue hyperplasia to this growth is unknown. We used a novel model of esophageal stretch to determine the cellular response to the strain stimulus. METHODS: Male Sprague-Dawley rats underwent transection of the distal esophagus. The distal stump was ligated and stretched over a silicone tube. The proximal esophageal stump was anastomosed to the stomach to restore continuity. After two, four, or seven days, the silicone tube was removed and the esophageal segment was measured and compared to its initial length. Sham animals had only a thin piece of silicone tubing placed. Standardized histologic sections were evaluated for wall thickness. Immunofluorescence with DAPI, Ki-67, and Myogenin antibodies was used to assess nuclear density, proliferation indices, and myoblast differentiation indices. RESULTS: Experimental animals demonstrated a significant increase in esophageal length compared to sham controls at four and seven days with no difference at two days. There was significant lengthening between four and seven days among the experimental animals. There was no change in wall thickness between experimental and sham animals at any time point. Nuclear density was increased at all time points, although this only reached significance at day four. Proliferation indices were significantly increased relative to sham controls at all time points. Esophageal strain induced significantly increased myoblast differentiation. CONCLUSION: In this novel rat model of esophageal strain, lengthening is associated with stable esophageal wall thickness, increased nuclear density, increased cellular proliferation, and increased myogenin expression. These data suggest that true tissue hyperplasia may contribute to the increased length seen after esophageal strain.

Immediate extubation after pediatric liver transplantation: a single-center experience.

The care of pediatric liver transplant recipients has traditionally included postoperative mechanical ventilation. In 2005, we started extubating children undergoing liver transplantation in the operating room according to standard criteria for extubation used for general surgery cases. We reviewed our single-center experience to determine our rates of immediate extubation and practice since that time. The records of 84 children who underwent liver transplantation from 2005 to 2011 were retrospectively reviewed. The immediate extubation rate increased from 33% during 2005-2008 to 67% during 2009-2011. Immediate extubation did not result in an increased reintubation rate in comparison with delayed extubation in the intensive care unit (ICU). Patients undergoing immediate extubation had a trend toward a shorter mean ICU stay as well as a significantly decreased overall hospital length of stay. Our findings suggest that there is a learning curve for instituting immediate extubation in the operating room after liver transplantation and that the majority of pediatric liver recipients can safely undergo immediate extubation.