Methods of reducing blood loss and non-blood substitutes.

A variety of techniques can aid the anaesthetist in reducing requirements for perioperative blood products. These include careful preoperative assessment of the patient, and employing techniques during surgery which reduce the blood pressure and help preserve the normal haemostatic mechanism. If the level to which haematocrit will be permitted to decrease is decided, then physiological crystalloid and/or colloid solutions may be used to maintain circulating volume. Where large volumes of fluids are required cardiac filling pressures should be monitored because of the complex nature of the fluid shifts which occur. There is no evidence that any one fluid (physiological crystalloids, colloids) is better than any other in terms of the incidence of perioperative morbidity.