When you have a wound, it goes through several healing processes, including bleeding and scabbing. As a result, it's also normal to have minimal to moderate discharge during the first week that appears thin, clear, or pale yellow.
But if you notice pus or thick, discolored drainage, especially in large quantities, it can indicate infection. To avoid this infection you must go through post-surgical drainage treatment. You can get more information regarding post-surgical drain from https://www.centese.com/.
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Some operations involve 'juicy parts' of the body, areas that make lots of fluids or juices. One example is the removal of an armpit (axilla), which is commonly done in conjunction with breast cancer surgery. After being operated on, the armpit produces a lot of fluid. The fluid could build up and cause pain if it is not drained.
The fluid pressure inside can cause the wound to stop healing. The surgical drain allows for extra fluid to drain away safely. The drain can be easily removed after the fluid has drained off.
Some operations do not require a drain. Your surgeon will let you know if one is required. Before the surgery, your surgeon will discuss whether or not you will require a drain. If you have surgical drains, follow-up appointments are especially important to keep.