After preoperative autologous donation and intraoperative hemodilution, intraoperative and postoperative blood salvage are the third and fourth components of a complete blood conservation program. (See "Surgical blood conservation: Preoperative autologous blood donation" and "Surgical blood conservation: Intraoperative hemodilution".)
In salvage techniques, blood that is shed during or after surgery (or trauma) is retrieved, processed in some fashion, and returned to the patient. Processing can be as simple as filtration or, most commonly, involves centrifugation and washing prior to re-transfusion.
INTRAOPERATIVE BLOOD SALVAGE
Intraoperative blood salvage (IBS) is also known as intraoperative autologous transfusion, intraoperative salvage, or intraoperative autotransfusion. IBS is unique among autologous transfusion methods because of its capacity to provide immense quantities of autologous blood very rapidly. In comparison, preoperative collection is limited by time constraints and patient tolerance, hemodilution is limited by blood volume and hemodynamic considerations, and postoperative salvage is limited by mechanical problems and concern about microbial contamination. IBS can be utilized throughout a surgical procedure and can replace blood in proportion to the volume lost. In certain situations, most notably liver transplantation, the rate and volume of replacement may be extraordinary .
Technology — The modern era of IBS technology began in the mid-1970s when the two currently available salvage systems – a centrifuge-based cell salvage instrument and a passive canister collection system (used with or without supplementary washing) – were introduced. The first commercially available instrument that could concentrate and wash salvaged red cells was the Cell Saver, introduced in 1974. Cell Saver technology has become so widely accepted (through five generations of Cell Savers) that virtually all similar IBS instruments are referred to as "cell savers."
The procedure starts with the surgeon aspirating blood from the surgical field through a suction wand attached to dual-channel tubing; this allows anticoagulant and blood to be mixed as the blood is aspirated. The aspirated blood is collected in a reservoir (usually a cardiotomy reservoir) until there is sufficient blood for processing. At this point, the salvaged blood is pumped into the centrifuge bowl, where it is concentrated and then washed with an isotonic electrolyte solution, most often saline. The processed red cell suspension is then pumped from the centrifuge bowl into an infusion bag. Modern cell salvage instruments can process a full reservoir of blood and provide 225 mL of washed, saline-suspended red cells with a hematocrit of 50 percent or more in approximately three minutes. Thus, a massively bleeding patient can be provided with the equivalent of 12 units of banked blood per hour.