Loss of blood at operation; a method for continuous measurement.

A method for continuous measurement of surgical blood loss has been devised and has been used clinically in some 400 cases. The method combines volumetric measure of the suction loss and gravimetric measure of the sponge loss. The volumetric device automatically deducts the volume of rinse water used and thus measures the amount of blood collected in a metering cylinder. The suction loss scale shows continuously the amount of blood in the metering cylinder. The gravimetric device requires counting sponges into the weighing pan, and turning a dial scale to deduct the initial weight of the sponges. The volume of blood in the sponges is then read directly on the dial scale. Use of the instrument, which is under the supervision of the anesthesiologist, adds about two minutes per hour to the time normally required for counting the sponges; and about three minutes per hour is required for tending the volumetric instrument.In clinical use, knowing constantly the amount of blood loss permits the starting of transfusion before serious deficit develops, and then maintaining the patient's blood volume at a predetermined optimum level. In some 400 cases the continuous measurement of the blood loss served as a reliable guide for carrying out the loss-replacement plan within close limits of accuracy.