What problems should be paid attention to in anesthesia for patients after radiotherapy

I often encounter radiotherapy patients in clinical practice.
Difficult airways should be the easiest for everyone to think of complications related to anesthesia; but besides this, what issues need to be considered for radiotherapy patients before surgery? After consulting the relevant knowledge on UpToDate, I will summarize and discuss with you.
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Early radiotherapy was dominated by nuclide decay, mainly cobalt-60 decay; Gamma Knife is composed of more than 200 cobalt-60 radioactive sources, all beams emitted by the radioactive source converge to the same point, called the isocenter.
The positioning accuracy of the array can reach 0.
1-1mm.

Nowadays, the most widely used linear accelerator can use photons, electrons or protons to achieve the purpose of treatment; among them, photons have strong penetrability and are the most widely used; electron penetrability is poor, but they have obvious advantages in skin and breast tumors; protons are the latest Application direction, the energy carried is released after entering the tissue for a certain distance, but the treatment product neutron may cause the second tumor risk.

There are various radiotherapy techniques, mainly external irradiation, among which three-dimensional conformal radiotherapy (3D-CRT) is the most commonly used technique to protect important organs near the tumor.

Late complications after radiotherapy are mostly related to tissue fibrosis.
The main complications related to anesthesia are mouth opening, radiation pneumonitis, and late complications of craniocerebral irradiation, which are briefly introduced below.

Difficulty in opening the mouth caused by radiotherapy is significantly reduced after the application of more precise intensity-modulated radiotherapy techniques, but the changes caused are almost irreversible; difficulty in opening the mouth is a common cause of difficult airways, and anatomical abnormalities caused by fibrosis of the throat mucosa can also be further To increase the difficulty of ventilation or intubation, sufficient attention and evaluation should be made before surgery.

Radiation-induced pulmonary fibrosis usually occurs after half a year, and it is mostly manifested as a decrease in restrictive ventilation caused by pulmonary interstitial changes.
Priority should be given to assessing activity tolerance, SpO2, blood gas or lung function before surgery.After craniocerebral irradiation, the risk of stroke is significantly increased in patients.
In the main cerebral blood vessels that are invaded, the circle of Wills may be more severely involved.
This may be related to the failure of the circle of Wills to normally compensate the blood supply to the brain in each area; at the same time, radiotherapy is definitely possible.
Cause cognitive dysfunction, the anesthesiologist should fully evaluate the above two aspects and inform the preoperative risk.

Reading "Miller's Anesthesiology", I found only the above short relevant explanations, which did not mention the possible risks of stroke and cognitive function caused by craniocerebral irradiation, but the above risks are higher in the perioperative period after radiotherapy.
Inform the necessary monitoring measures before the conversation.

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