Patient controlled analgesia, or PCA, was developed in the 1960s. This mode of opioid administration allows patients to directly respond to their individual levels of pain. It is estimated there are now somewhere between six and 15 million uses annually.Two parallel sections enclosed in cream coloured metal casing and joined in the centre via a brown metal section that also forms the base and stand. The left side has a dark brown perspex cover with a small brushed metal latch and handle. The right has a grey metal panel with dial, knobs and a rolled paper dispenser. A clear plastic intravenous bag is attached to the device by a clear plastic tube.There is also a black plastic coated wire attached to a handle with a red button on top. This is used for the patient to administer the analgesia. analgesia, intravenous, flinders medical centre, janssen scientific instruments, patient controlled