Endoscopic endocrine neck surgery with carbon dioxide insufflation: The effect on intracranial pressure in a large animal model

Background. Endoscopic endocrine neck surgery requires insufflation, with c arbon dioxide (CO2) at 10 to 15 mm Hg, which may decrease the cerebral veno us return and increase intracranial pressure. This study evaluated the effe ct of CO2 neck insufflation on intracranial pressure (ICP) and hemodynamic parameters. Methods. Fifteen pigs underwent endoscopic thyroid dissection. Insufflation was performed with CO2 at 0 (sham), 10, 15, and 20 mm Hg and with helium a t 20 mm Hg with 3 pigs in each group. ICP, mean arterial pressure, central venous pressure (CVD), cardiac output, and blood gas were measured at basel ine, 30, 60, and 120 minutes. Results, There were no differences in mean ICP between the sham group and C O2 insufflation at 10 mm Hg. Mean ICP increased significantly with CO2 at 1 5 and 20 mm Hg and with helium at 20 mm Hg A significant increase in CVP oc curred in pigs operated with CO2 at 20 mm Hg. We observed jugular vein coll apse under all insufflation pressures, however, pigs operated at 10 mm Hg w ere able to maintain an intermittent blood flow. Conclusions. A severe increase in ICP occurs with insufflation pressures hi gher than 15 mm Hg; possibly as a result of decreased cervical venous blood flow. Carbon dioxide insufflation up to 10 mm Hg does not alter ICP and is recommended for clinical application in endoscopic neck surgery.