an autotransfusion system for collecting blood from a patient and reinfusing the blood back into the patient is disclosed . the system includes a collection unit , a manually operable portable suction evacuator removably connected to the collection unit , and a blood reinfusion bag removably connected to the collection unit . the collection unit includes a collection chamber that is oversized relative to the volume of blood that the unit is intended to contain , and an airflow port located and oriented in the collection chamber to prevent blood from leaking into the port when the collection unit is oriented upright or on its side . when connected to the patient , the collection unit and portable suction evacuator are maintained free of blood by enclosing them within a substantially transparent , flexible envelope . the envelope enables the unit and evacuator to be connected and set - up for proper operation while preventing blood from contacting the outer surfaces of the unit and evacuator .