Effects of aerobic exercise on depression: a controlled study.

Rejection of catheters is generally thought to be due to patients pulling out their catheters, but we found circumstantial evidence for this in only one third of cases. Some catheters with smaller balloons drop out spontaneously, perhaps owing to laxity of the pelvic floor or urethral dilatation caused by repeated catheterisation, and others are expelled forcibly, presumably owing to uninhibited contractions of the bladder. Urinary catheters may therefore drop out, be pushed out, or be pulled out. The life expectancy of catheters in this group of patients suggests the type of catheter that should be used. We recommend cheaper latex catheters and think that expensive "long life" silicon catheters are inappropriate in most long stay patients. Rejection of catheters is common in poorly mobile old people with cognitive impairment. It is associated with urethral trauma and may result in septicaemia. Long term catheterisation should therefore be considered only when other methods to promote continence and provide comfort have failed.3 Further work is needed to determine why some patients pull out their catheters and whether bladder stabilising drugs might reduce episodes of spontaneous rejection of catheters.