Fluid shifts between extracellular and intracellular compartments have not been characterized during laparoscopic surgery. Bioimpedance analysis consists of the non-invasive measurement of the characteristics of tissues after an electrical current has been applied. Using standard regression equations after application of different levels of current, intracellular and extracellular volumes may be extrapolated. We compared the fluid shifts measured by bioimpedance techniques in an animal model of elective laparoscopic and open general surgery, and correlated them with central venous pressures (CVP). Under institutional approval, we performed a five laparoscopic and five open right hemicolectomies in ten male white New Zealand rabbits. In all instances, the procedure lasted 90 minutes, and rabbits were given 10 ml/kg/hr intravenous fluids as a standard rate. Serial bioimpedance data was collected at 15 minute intervals, including phase angle, capacitance, resistance and reactance. There were no major intraoperative complications or deaths. In all animals, CVP and bioimpedance data suggested minimal changes in total body water or its distribution. A sample data plot, normalized to unity, is presented for the variables of CVP, phase angle, capacitance, resistance and reactance for a representative animal.In the rabbit model, overall fluid homeostasis was maintained by the animals during both laparoscopic and open procedures. There were no appreciable fluid shifts between intra and extracellular compartments during either laparoscopic or open surgery, as measured by serial bioimpedance determinations as well as CVP measurements. Fluid shifts are not substantially different between routine laparoscopic and open surgery. In addition, this preliminary data suggests that non-invasive bioimpedance may be used in place of CVP measurements for physiologic monitoring during routine procedures.