A drainage device and method of draining a biological fluid from the body of a patient is disclosed. The drainage device includes a drainage tube, a pressure relief assembly, a cleaner assembly, and a housing. The drainage tube includes an array of apertures in it through which biological fluid from the patient can flow for collection by a collection canister. The cleaner assembly includes a squeegee unit configured to be pulled in a proximal direction from a distally located position in the drainage tube to scrape any biological material adhering on the inner surface of the drainage tube and carry it to the collection canister. The pressure relief assembly serves to equalize the pressure in the drainage tube as it is being cleaned. The squeegee unit also acts as a pressure relief valve to equalize the pressure within the drainage tube when the squeegee unit is retracted back to its distally located position.
