End-tidal carbon dioxide

End-tidal carbon dioxide (ET-CO2) values and capnography can provide useful diagnostic information concerning critical events in the operating room, including those that may be life-threatening. The clinical interpretation of changes to the capnogram and the numerical ET-CO2 value displayed during a surgical procedure can alert the anesthesia provider to a variety of critical perioperative events. The concepts of autoregulation and CO2 reactivity are important to the care of patients undergoing neurosurgical procedures. The levels of CO2 have proven to influence autoregulation and play an important role in the recovery from traumatic brain injury (TBI). Within clinically relevant ranges, cerebrovascular reactivity to CO2 seems to remain intact with both inhaled and intravenous anesthetic agents. A recent randomized, crossover trial was conducted to determine the efficacy of moderate hyperventilation on patients undergoing elective craniotomy for resection of supratentorial tumors with either propofol or isoflurane anesthesia.