Aggressive management of surgical emergencies

Consequences of surgical stress on the kinetics of skin wound healing: partial hepatectomy delays and functionally alters dermal repair

The objective was to determine the significance of surgical trauma in dermal wound healing. Using intravital microscopy, we analyzed the healing kinetics of full-thickness dermal wounds in the ears of SKH1 mice. Partial hepatectomy (pHx) simulated major surgical trauma, while laparotomy only served as a sham operation (sham). Animals without abdominal surgery served as controls (control). Laparotomy wounds were analyzed for biomechanical qualities and collagen deposition. Morphological characterization of skin repair was performed by histology/immunohistochemistry. In vitro cell assays assessed the paracrine effects of surgical stress. PHx caused a transient increase in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels and led to weight loss, reflecting the host's overall response to surgery. Wound closure in pHx animals was delayed vs. control and sham animals, as indicated by significantly lower values of epithelialization and neovascularization over 10 days. Ear wound histology further revealed a provisional wound matrix with a reduced microvessel density. Moreover, pHx-laparotomy wounds showed a reduced bursting strength coexisting with significantly decreased collagen content. PHx and sham serum caused a significant alteration in in vitro fibroblast viability. Skin healing is dependent on the extent of surgery and is influenced by its paracrine effects. Therefore, considerable effort should be focused on the development of strategies limiting surgery-associated perturbations of dermal repair.

The role of prebiotics and synbiotics in critically ill patients

PURPOSE OF REVIEW

To examine current knowledge regarding the role of prebiotics in critical illness when administered singly or in combinations with probiotics (synbiotics).

RECENT FINDINGS

Recent experimental and clinical studies support the fact that bioecological intestinal control with early enteral nutrition enriched with synbiotics may reduce systemic inflammation, improve the immunological status of the intestinal mucosa and help prevent infections in critically ill patients. Three prebiotics, oligofructose, galactooligosaccharides and lactulose are able to modify the balance of intestinal microbiota. It appears that treatment with synbiotics during critical illness should restore the balance of microbial communities in a beneficial way with positive effects on intestinal permeability and bacterial translocation. Only data from small trials are currently available to support use of prebiotics and synbiotics in the treatment of different clinical scenarios. However, in some critical conditions, this supplementation has so far not been effective.

SUMMARY

Numerous questions about the molecular mechanisms of action or clinical indications of prebiotics remain unanswered. Large, randomized, multicentre trials are necessary to precisely define the role of prebiotics as therapeutic agents in critical illness. These trials must identify clinically significant improvements in relevant clinical endpoints before any large-scale usage is advocated for critical illness.

Immunoparalysis after multiple trauma

The immunological sequelae following multiple trauma constitute an ongoing challenge in critical care management. The overall immune response to multiple trauma is a multilevel complex interdependently involving neurohormonal, cellular and haemodynamic factors. Immunoparalysis is characterised by a reduced capacity to present antigens via downregulated HLA-DR and an unbalanced monocyte-T cell interaction. Trauma-induced death of functionally conducive immune cells in the early recovery phase is significant in the emergence of posttraumatic multiple organ dysfunction or failure. Novel findings may contribute to more appropriate immunomonitoring and improved treatment. We must consider the preservation and support of immune function as the ultimate therapeutic goal, which may override the current strategy of simply antagonising excessive pro- or anti-inflammatory immune responses of the severely injured person. This review focuses on the injury-induced conduct of key immune effector cells and associated effects promoting immunoparalysis after multiple trauma.