A medical device is provided for irrigation of a patient wound site. The device contains a tube having a proximal portion adapted to receive an irrigation solution, a distal portion having a nozzle and an intermediate portion for transporting the solution. The tube has a barrel portion that may be manipulated by a user to position the device relative to the wound site. A distinctive nozzle has a body formed with a distally leading channel presenting a semispherical first spatial conformation and a proximally leading opening formed in the body presenting a second spatial conformation intersecting the semispherical terminus. This geometry, derived from principles of flow mechanics discussed herein, defines what will be described as an “effective diameter” of the nozzle. An assembly and system utilizing the device am also disclosed. The invention utilizes a fluid-isolating durable peristaltic pump for a continuous flow of irrigation solution, along with a single use tube set that embodies the device.