Evaluation of capnography to predict arterial PCO 2 in neurosurgical patients.

This study was designed to see if capnography could be used to predict PaCO 2 so as to adjust ventilation to maintain PaCO 2 within the desired range in head-injured patients undergoing prolonged mechanical ventilation. It was further designed to see if P ETCO 2 could accurately predict PaCO 2 based on only one arterial blood gas (ABG) measurement or if more frequent, i.e., daily, ABG measurements were required.