Background and Goal of Study:
The gamma knife is a treatment for cerebral arteriovenous malformation or some types of brain tumor. Patients are received therapy in the treatment room where is separated from the medical staff room. There is no guideline about how to monitor patients during gamma knife, because patients are received only a little local anesthesia and sedation medicine before treatment, and don't feel any pain during therapy. So many brain surgeons of gamma knife believe that they can complete their therapy without any fear. We studied how gamma knife patients changes their respiratory condition and when we should pay attention during treatment.
Materials and Methods:
We selected patients scheduled gamma knife treatment at Tokyo women's medical university hosiptal from April 2016 to March 2017, and checked patients' oxygen saturation using Capnostream (Covidien japan corp) during gamma knife irradiation. Capnostream can save saturation data every 5 second. After treatment, we made scatter plots from patients' data.
Results and Discussion:
We got 171 patients data. Within that, 103 patients (60.2%) reduced their oxygen saturation under 93 during treatment, and 38 (22.2%) patients had oxygen desaturation under 90.  And,by looking at the scatter plots, we found many patients start reducing their oxygen saturation from 15-20 minutes after entering the treatment room.
Conclusion(s):
During the gamma knife therapy, many patients may have bad respiratory conditions. Especially, we should pay attention from 15 minutes have passed after starting treatment.


08 / The necessity of monitorng oxygen saturation during gamma knife radio surgery