Dementia in the elderly: diagnosis and assessment.

Abstract

In operation the pump is connected to the patient's bladder (B), to a bag under the bed (A), and to a bottle of normal saline over the bed (C) (fig. 3). In the piston's normal or resting position the urine from the bladder will run directly into the bag under the bed along the groove in the piston. In the event of the cath eter becoming blocked the pump handle is rotated clockwise through 90 degrees. This links up the groove in the piston with the port in the cylinder connected to the bottle over the bed. The piston is then withdrawn to its limit, thus filling the cylinder with saline. When the handle is rotated through a further 90 degrees the contents of the cylinder are connected to the bladder into which they are emptied when the piston is pushed into the cylinder. In this position only one movement is allowed by the location of the peg in the piston, and this is upwards, with drawing fluid from the bladder. A further rotation of 90 degrees brings the groove in the piston next to port A, into which the contents of the cylinder can then be pumped. The final rotation of the handle through 90 degrees brings the piston back to its starting point, the groove joining port B to port A. No internal dimension within the pump is less than t in (6 mm) in diameter and this appears to be adequate to prevent blockage by blood clots. The pump has been used successfully on patients and the nursing staff find the sequence of operations easy to follow, as the pump allows only one movement from a given position. The pump can break up quite large clots and eject them into the drainage bag. Because any fluid used to wash out the bladder is metered into the drainage bag urine output is easy to calculate. The piston of the prototype pump was made from poly tetrafluoroethylene and the cylinder was made from Perspex. The device has been sterilized in glutaraldehyde (Cidex) as the present materials do not withstand autoclaving. The possibility of making the pump out of stainless steel in a form which will allow it to be taken apart for cleaning and autoclaving is being investigated.