The spring balance: a simple monitoring system for fluid overload during hysteroscopic surgery.

Fluid overload may arise during hysteroscopic surgery, caused by absorption of fluid used to distend the uterus. Continuous monitoring of the fluid balance is required to prevent this serious complication. Commercial equipment does not serve this purpose adequately. We describe a simple solution. We weigh the inflow and outflow volumes together on a spring balance; this method provides information about fluid balance, since any fluid lost as spillage or by absorption is reflected by a loss of weight on the balance. The method is simple, accurate, and inexpensive, and the components can be purchased readily.