Deep propofol sedation for vacuum-assisted bite-block immobilization in children undergoing proton radiation therapy of cranial tumors.

Background: Vacuum-assisted bite-block immobilization of the head is a reliable technique for reproducible precise head positioning as used for proton radiation in adults. We report preliminary experience using deep propofol sedation without an artificial airway in children undergoing proton radiation of cranial tumors requiring vacuum-assisted bite-block immobilization.

Methods: Sedation was started with a bolus of i.v. midazolam followed by repeated small boluses of propofol as required to tolerate bite-block insertion and patient positioning. Sedation was maintained by continuous propofol infusion until removal of the bite block. Oxygen was administered by a nasal cannula. SpO2, endtidal CO2 taken at the nose and respiratory adverse events such as coughing, bucking, airway obstruction, regurgitation or aspiration were recorded. Data are mean+/-sd.

Results: Ten children aged 2.6+/-0.8 years were treated to date. For each child, cumulative 26.7+/-1.9 radiation fractions were administered. Propofol dose administered for induction, bite-block insertion and patient positioning was 3.9+/-0.5 mg.kg(-1). Time from insertion to removal of the bite block lasted 48.3+/-6.2 min. Endtidal CO2 values were 5.6+/-0.8 kPa (43+/-7 mmHg) and SpO2 values were 98.3+/-1.9% with spontaneous breathing, supplemental oxygen and bite block inserted. No respiratory adverse events occurred during the 267 sedation procedures performed.

Conclusion: Deep propofol sedation without the use of an artificial airway is an interesting technique for vacuum-assisted bite-block immobilization in young children undergoing precise radiation therapy of cranial tumors. However, simultaneous individual anesthetic challenges require pediatric anesthesiologists highly experienced with the pediatric airway, clinical alertness and closed monitoring.