PSI - Department of Anaesthesia

Course of anaesthesia in small children undergoing proton radiation therapy at the PSI 

Proton radiation therapy in small children at the Paul Scherrer Institute in Villigen is done under general anaesthesia (normally in the form of deep sedation with spontaneous breathing). The children are treated on a day case basis 4-5 times a week. At the kids corner in the waiting room they can stay with their parents, brothers and sisters and play until the induction of anaesthesia starts.
Parents are allowed to stay with their children in the anaesthesia room until the patient is asleep. In general, the patients have an indwelling central venous catheter (Port-a-cath or Broviac, Cook or Hickman Catheter) allowing a smooth induction.
As soon as the child is asleep, oxygen is administered through the nasal prongs and the monitoring is installed which includes pulse oxymetry, blood pressure, electrocardiogram (ECG) and body temperature measured at the ear. The nasal prongs serve also as a monitoring of spontaneous breathing as the expired CO2 in each breath can be measured. Anaesthesia is maintained with propofol continuously administered by a syringe infusion pump.
Transportation to the CT room and the Gantry radiation room is done on a special transporter. The child is placed inside his/her own individual “whole body mould” mounted on the transporter. In cases of radiotherapy in the head and neck area, the head is fixed with an individual bite block or mask.
Before each proton therapy session a CT scan of the field is performed and the current positioning is compared with the positioning in the first CT scan for safety reasons.
The Gantry is insulated from the environment by thick concrete walls and can be reached from the CT room through a 15m long corridor.
The patient table and the mobile gantry can be moved to different positions so that the tumour can be targeted from different directions. During radiation treatment nobody is allowed to stay in the Gantry room with the patient.
By means of video cameras the patient, the vital signs monitoring system and the syringe infusion pump is supervised. The vital data are transferred from the patient monitor to the central monitors in the control room and in the anaesthesia room. Pulse tone, acoustic alarms of the monitor or infusion pump are transferred by a microphone from the Gantry to the control room.
After radiation therapy the child is brought back to the anaesthesia room and bedded in his/her bed. The intravenous anaesthetic is stopped, the central venous catheter flushed with NaCl 0,9% and heparin. Once a week one blood sample is withdrawn for control (by order of the paediatric oncologist.
In the recovery room the parents (and siblings) accompany the child again. As long as the child is sleeping, oxygen is administered and heart rate as well as oxygen saturation are monitored. The patient is allowed to eat and drink immediately when fully awake. Normally 30 – 60 minutes after the patient is fully awake, the patient and parents can leave the hospital for home.