Dear Editor, Proton therapy involves the acceleration of protons in a rotating gantry and focusing it upon the tumour, where the electrons split from the atom, leading to cell nucleus damage. Everything behind the tumour remains free from radiation. Hence, it is an important treatment modality in paediatric cancer patients. It requires delivery of multiple fractions of the total radiation dose, given daily over several weeks.1 Although the treatment is painless, children have difficulty maintaining immobility, required to ensure precision of delivery. Parental separation anxiety combined with presence of healthcare personnel necessitate general anaesthesia. Furthermore, local immobilisation for consistent delivery of the beam is achieved with an individualised patient immobilisation system from Orfit, made from a thermoplastic material.2 The role of an anaesthesiologist is facilitating immobilisation of the child, weighed against unique ergonomics and remote monitoring, for safe and effective anaesthesia.1,3,4 We present anaesthesia management of a paediatric case of left orbital rhabdomyosarcoma with a fitted head and neck immobilisation mould. A 6-year-old child, weighing 20 kg with relapsed left orbital rhabdomyosarcoma, was planned for proton therapy (20 cycles). We planned general anaesthesia, with a supraglottic airway (SGA). Cutout was made in the immobiliser mould, over the mouth to accommodate the SGA (Ambu AuraGain size-2) Figure 1. Anaesthesia management included oral midazolam for premedication followed by induction of anaesthesia with sevoflurane. Intravenous (IV) 24G access was taken after induction, and the SGA was inserted and attached to the Limb-O circuit (length 9 feet). Anaesthesia was maintained on sevoflurane in oxygen: air mixture with spontaneous respiration. Continuous monitoring was done as per ASA standards with a multipara monitor. Both the gantries were rotating over a belt, as also the patient table was rotated to focus the beam nozzle Figure 2. Initially, the child’s gantry duration was 80 min, after which he was discharged home with an IV cannula requiring changes every 3–4 days; however, for the subsequent ten cycles, anaesthesia was successfully induced with 40–60 mg of IV propofol, reducing the gantry time to 45–50 min, and for the remaining cycles, anaesthesia was maintained safely using propofol total intravenous anaesthesia (TIVA) (4–6 mg/min) with spontaneous respiration and oxygen-insufflation, reducing the gantry time further to 25–35 min and resulting in no reported complications.Figure 1: A hole made through the head and neck immobilisation mould (Orfit) for the supraglottic device (SGA). The blue arrow shows the placement of the extra Gamgee pads to prevent the SGA displacementFigure 2: The changing positions of the table along with the rotating gantry. The picture on the extreme right shows the remote monitoring of the patient via multiple camerasProton therapy is an example of non-operating room anaesthesia and is housed far away from the major operating theatres. It was the first case to be performed under anaesthesia at our centre. The rigid fit of the immobiliser mould restricted the access to airway, and the need for repetitive anaesthesia was challenging, along with unique ergonomics. Our gradual change from SGA to TIVA with oxygen insufflation showcased our growing comfort in later cycles, at par with internationally reported standards.1,3,4 An international survey reported that 57% respondents (n = 8) preferred TIVA with propofol and an unprotected airway, 36% (n = 5) preferred general anaesthesia with sevoflurane and a laryngeal mask airway and only 7% (n = 1) preferred intubation.4 The reported complications range from 0 to 2% with bradycardia, aspiration, laryngospasm and bronchospasm being the only ‘rare’ complications being reported.1,3,4,5 A trained paediatric anaesthesiologist is imperative. Careful patient selection and communication between the radiation oncologist, medical physicist and anaesthesiologists are central to safe conduct. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Author contribution Dr. Anjana Sagar Wajekar: Drafting the letter, literature review, consent taking, data collection, data storage and confidentiality. Dr. Paras Anjaria: Conduct of case, writing the letter, literature review, consent taking, data collection. Dr. Bhakti Trivedi: Concept, design, conduct of case, ensuring scientific accuracy. Dr. Ashwini Rane: Concept, writing the letter, literature review, ensuring scientific accuracy Disclosure of use of artificial intelligence (AI)-assistive or generative tools Not Used. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Wajekar et al. (Thu,) studied this question.