Important factors in the maintenance of homeostasis in the surgical patient

Three factors that influence homeostasis are discussed: fluids and electrolytes, energy and nutrition, and immune response mediators. Cell injury induces changes in the sodium-potassium pump that disrupt fluid and electrolyte homeostasis, and surgery causes changes in functional extracellular fluid. Caloric requirements increase in proportion to the severity of the injury, and are generally greater than expected. Both parenteral and enteric feeding restore alanine and glutamine levels toward normal. Studies suggest that some of the adverse effects of surgery on homeostasis may be alleviated by specific treatments. A major key in modulating the stress response to surgery may lie in controlling immune response mediators, in particular cachectin, which has been shown to cause effects identical to those of septic shock. Recent studies have indicated that injections of small doses of specific monoclonal antibody to cachectin can avert all of the mediator's adverse effects.