The research on the effect of temperature of electro-surgical unit to surgical smoke distribution in theatre-in vitro and simulation study

In electro-surgery, surgical smoke was hazard to surgeons and patient in theatre. In order to institute effective countermeasures, quantifying of the effect of tip temperature of electro-surgical unit to surgical smoke distribution in theatre was studied. The relation of tip temperature to power of electro-surgical unit through in vitro cutting experiment. Based on experiment data, the mathematical model was established to simulate the electro-surgery in laminar operation room. As the power of electro-surgical knife increased, the knife tip temperature increased. Total content of (CO, CO2, CH4, NH3) in waste gas and net flow rate of waste gas at outlet increased with the rising temperature of knife tip and formation rate of condensed tar droplets and non-viable particles also increased. Based on simulation, it was found that The maximum height of surgical smoke rising right above the incision of electro-surgical unit was increased with rising temperature of electro-surgical knife tip. There was a spread route of dispersed surgical smoke near the walls of theatre through natural convection. The polynomial fitting relationship was derived. As the tip temperature of knife increased from 200 to 500 degrees C, maximum ascending height of surgical smoke right above the incision position of electro-surgical unit increased from 1.1 m to 1.45 m. When the tip temperature of electro-knife was more 400 degrees C, the CO content in the surgeon's operating zone was more than 200 ppm, which would cause the surgeon's HbCO level increased. As the patient's tissue in the wound during operation was open, when the electro-knife of more than 400 degrees C, the content of condensed tar droplets and in-viable particle was higher than 20 g/m3 and 12 g/m3 in the zone around patient's wound of open tissue, which should be hazard to health of patient.