History and Objectives: Considering the importance of respiratory changes following neurosurgical operations in patients under general anesthesia and with regard to its basis (Reduction of arterial PCo2), this study was conducted in Naghavi hospital in Kashan from 1998 to 1999.

Materials and Methods: The semi-experimental strategy of this study was carried out on 113 referrals of operation room. Then, the parameters EtCO2, SPO2 and RR were determined in addition of type of operation and its duration.

Results: Out of 113 patients, 70 cases (61.9%) were male and 43 cases (38.1%) were female and they had an age range of 0-75 years with the highest frequency greater than 40 years. Level of parameters was greater in men than women. In addition, EtCO2, SPO2 and RR in cases with an age greater than 40 years was less than from cases with an age range 20-40 years. As it is expected, the changes were greater for operations longer than 2h in relation to operation less than this duration. Meanwhile, the observed differences were significant statistically.

Conclusion and Recommendations: A significant change was observed in respiratory indices following neurosurgical operation and its differences were dependent on position, duration and type of surgery. Therefore, it is recommended to continually monitor respiratory parameters through capnography and ABG and to conduct more studies in this field.