Upgrading your medical equipment is a key aspect in Two Point Hospital. Your basic equipment will not increase the probability of treating your patients. Although it barely makes any difference in case of standard illnesses, more complicated diseases will be hard to treat.
An upgrade needs to be unlocked first. This can happen in two ways. You can receive a special technology as a reward for your achievements in a given hospital (this usually includes getting three stars in a hospital).
The second solution is to conduct a research. Once you have your research room ready, you will have an option to start research projects. This way, you can unlock new rooms and upgrades for your existing rooms. Unfortunately, this takes time as researching new technologies requires you to generate enough research points. The speed of the progress depends on the number of doctors assigned to the project, and design elements located in the room.
Discover a technology and you will be able to implement it. All you need is a janitor with mechanics qualifications. Select equipment that you want to upgrade and click the appropriate icon (see screenshot).
The selected piece of equipment will start upgrading. Keep in mind that the cabinet, in which the process is taking place, will be out of order. Thus, if you have more than one device of a given type in your hospital, you can feel free to upgrade it. This way, you will not delay your work. If you really need to upgrade a piece of medical equipment that is one of a kind, try to perform the upgrade when there are no patients waiting in line to use it. If that is not an option, pick a moment when there are 1-2 people waiting.