Drain (surgery)

Tube used to remove pus, blood or other fluids from a wound

A surgical drain is a tube used to remove pus, blood or other fluids from a wound, body cavity, or organ. They are commonly placed by surgeons or interventional radiologists after procedures or some types of injuries, but they can also be used as an intervention for decompression. There are several types of drains, and selection of which to use often depends on the placement site and how long the drain is needed.

Drains help to remove contents, usually fluids, from inside the body. This is beneficial since fluid accumulation may cause distension and pressure, which can lead to pain. For example, nasogastric (NG) tubes inserted through the nose and into the stomach can help remove stomach contents for patients who have a blockage further along in their gastrointestinal tract. After surgery, drains can be placed to remove blood, lymph, or other fluids that accumulate in the wound bed. This helps to promote wound healing and allows healthcare providers to monitor the wound for any signs of internal infection or damage to surgically repaired structures. Drains may be classified as passive or active, open or closed, and external or internal. Passive drains rely on gravity or capillary action to remove fluid, whereas active drains rely on a suction/vacuum force, whether that be through connection to wall suction, a portable suction device, or a bulb that has been squeezed to create a vacuum. Open drains are commonly used for superficial wounds and drain into dressings or a stoma bag. Closed drains are tubes or other channel like structures that are connected to a container, thereby creating a closed system. External drains go from inside the body to outside the body and can be seen, while internal drains are completely inside the body. An example of an internal drain is a ventriculo peritoneal shunt, which is a tube that connects ventricles of the brain to the peritoneal cavity. This helps remove extra cerebrospinal fluid from the brain. Accurate recording of the volume of drainage as well as the contents is vital to ensure proper healing and monitor for excessive bleeding. Depending on the amount of drainage, a patient may have the drain in place one day to weeks. Drains will have protective dressings that will need to be changed daily/as needed. The routine use of drains for surgical procedures is diminishing as better radiological investigation and confidence in surgical technique have reduced their necessity. It is felt now that drains may hinder recovery by acting as an 'anchor' limiting mobility post surgery and the drain itself may allow infection into the wound. In certain situations their use is unavoidable.

Drains risk becoming occluded or clogged, resulting in retained fluid that can contribute to infection or other complications. Thus efforts must be made to maintain and assess patency (condition of being open) when they are in use. Once a drain becomes clogged or occluded, it should be removed, as it is no longer providing any benefit.