Intraoperative blood salvage
Encyclopedia
Intraoperative blood salvage, also known as autologous blood salvage, is a medical
procedure involving recovering blood lost during surgery
and re-infusing it into the patient.
It has been used for many years and gained greater attention over time as risks associated with allogenic blood transfusion have seen greater publicity
and more fully appreciated. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. These are used frequently in cardiothoracic and vascular surgery
, in which blood usage has traditionally been high. With a greater effort to avoid adverse events due to transfusion
there has also been an emphasis on blood conservation (see bloodless surgery
).
, AIDS/HIV, West Nile virus
(WNV), and transfusion-transmitted bacterial infection. Human errors such as misidentifying patients and drawing blood samples from the wrong person present much more of a risk than transmissible diseases.
Additional risks include transfusion related acute lung injury
(TRALI), a potentially life-threatening condition with symptoms such as dyspnea
, fever
, and hypotension
occurring within hours of transfusion, and also transfusion-associated immunomodulation, which may suppress the immune response and cause adverse effects such a small increase in the risk of postoperative infection.
Other risks such as variant Creutzfeldt-Jakob disease
(vCJD), an invariably fatal disease, remain worrisome. Blood centers worldwide have instituted criteria to reject donors who may have been exposed to vCJD. Screening for transmissible diseases and deferral policies for vCJD designed to improve safety have contributed to shrinking the donor pool. Blood shortages exist in the United States and worldwide. In many industrialized countries 5% or less of the eligible population are blood donors.
As a result, the global medical community has increasingly moved from allogenic blood (blood collected from another person) towards autologous infusion, in which patients receive their own blood. Another impetus for autologous transfusion is the position of Jehovah's Witnesses on blood transfusions
. For religious reasons, Jehovah's Witnesses will not accept any allogeneic transfusions from a volunteer's blood donation
, but may accept the use of autologous blood salvaged during surgery to restore their blood volume and homeostasis during the course of an operation, although not autologous blood donated beforehand.
. There are several so-called bloodless options. These include:
Intraoperative blood salvage has been used for many years, especially in cardiothoracic and vascular surgery, where blood usage has traditionally been high.
Regardless of manufacturer, there are many types of cell processors. Cell processors are red cell washing devices that collect anticoagulated shed or recovered blood, wash and separate the red blood cells (RBCs) by centrifugation, and reinfuse the RBCs. RBC washing devices can help remove byproducts in salvaged blood such as activated cytokine
s, anaphylatoxin
s, and other waste substances that may have been collected in the reservoir suctioned from the surgical field. However, they also remove viable platelets, clotting factors, and other [plasma proteins] essential to whole blood and homeostasis
. The various RBC-savers also yield RBC concentrates with different characteristics and quality.
Direct transfusion is a blood salvaging method associated with cardiopulmonary bypass (CPB) circuits or other extracorporeal circuits (ECC) that are used in surgery such as coronary artery bypass grafts (CABG), valve replacement, or surgical repair of the great vessels. Following bypass surgery the ECC circuit contains a significant volume of diluted whole blood that can be harvested in transfer bags and re-infused into patients. Residual CPB blood is fairly dilute ([Hb] = 6–9 g/dL; 60–90 g/L) compared to normal values (12–18 g/dL; 120–180 g/L) and can also contain potentially harmful contaminants such as activated cytokines, anaphylatoxins, and other waste substances that have been linked to organ edema
and organ dysfunction and need a diuretic
to reverse.
Hemofiltration or ultrafiltration devices constitute the third major type of blood salvage appearing in operating rooms. In general, ultrafiltration devices filter the patient's anticoagulated whole blood. The filter process removes unwanted excess non-cellular plasma water, low molecular weight solutes, platelet inhibitors and some particulate matter through hemoconcentration, including activated cytokines, anaphylatoxins, and other waste substances making concentrated whole blood available for reinfusion.
Hemofilter devices return the patient's whole blood with all the blood elements and fractions including platelets, clotting factors, and plasma proteins with a substantial Hb level. Presently, the only whole blood ultrafiltration device in clinical use is the Hemobag. These devices do not totally remove potentially harmful contaminants that can be washed away by most RBC-savers. However, the contaminants that are potentially reduced by using RBC-savers, as shown by data from in vitro
laboratory tests, are transient and reversible in vivo
with hemostatic profiles returning to baselines within hours. The key is that coagulation
and homeostasis are immediately improved with the return of concentrated autologous whole blood.
Over the years numerous studies have been done to compare these methods of blood salvage in terms of safety, patient outcomes, and cost effectiveness, often with equivocal or contradictory results.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
procedure involving recovering blood lost during surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
and re-infusing it into the patient.
It has been used for many years and gained greater attention over time as risks associated with allogenic blood transfusion have seen greater publicity
Publicity
Publicity is the deliberate attempt to manage the public's perception of a subject. The subjects of publicity include people , goods and services, organizations of all kinds, and works of art or entertainment.From a marketing perspective, publicity is one component of promotion which is one...
and more fully appreciated. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. These are used frequently in cardiothoracic and vascular surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, in which blood usage has traditionally been high. With a greater effort to avoid adverse events due to transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
there has also been an emphasis on blood conservation (see bloodless surgery
Bloodless surgery
Bloodless surgery is a term that was popularized at the beginning of the 20th century by the practice of an internationally famous orthopedic surgeon, Adolf Lorenz, who was known as "the bloodless surgeon of Vienna." This expression reflected Lorenz's methods for treating patients with noninvasive...
).
Background
Providing safe blood for transfusion remains a challenge despite advances in preventing transmission of hepatitis B, hepatitis CHepatitis C
Hepatitis C is an infectious disease primarily affecting the liver, caused by the hepatitis C virus . The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years...
, AIDS/HIV, West Nile virus
West Nile virus
West Nile virus is a virus of the family Flaviviridae. Part of the Japanese encephalitis antigenic complex of viruses, it is found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, domestic...
(WNV), and transfusion-transmitted bacterial infection. Human errors such as misidentifying patients and drawing blood samples from the wrong person present much more of a risk than transmissible diseases.
Additional risks include transfusion related acute lung injury
Transfusion related acute lung injury
In medicine, transfusion related acute lung injury is a serious blood transfusion complication characterized by the acute onset of non-cardiogenic pulmonary edema following transfusion of blood products....
(TRALI), a potentially life-threatening condition with symptoms such as dyspnea
Dyspnea
Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...
, fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, and hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
occurring within hours of transfusion, and also transfusion-associated immunomodulation, which may suppress the immune response and cause adverse effects such a small increase in the risk of postoperative infection.
Other risks such as variant Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease
Creutzfeldt–Jakob disease or CJD is a degenerative neurological disorder that is incurable and invariably fatal. CJD is at times called a human form of mad cow disease, given that bovine spongiform encephalopathy is believed to be the cause of variant Creutzfeldt–Jakob disease in humans.CJD...
(vCJD), an invariably fatal disease, remain worrisome. Blood centers worldwide have instituted criteria to reject donors who may have been exposed to vCJD. Screening for transmissible diseases and deferral policies for vCJD designed to improve safety have contributed to shrinking the donor pool. Blood shortages exist in the United States and worldwide. In many industrialized countries 5% or less of the eligible population are blood donors.
As a result, the global medical community has increasingly moved from allogenic blood (blood collected from another person) towards autologous infusion, in which patients receive their own blood. Another impetus for autologous transfusion is the position of Jehovah's Witnesses on blood transfusions
Jehovah's Witnesses and blood transfusions
Jehovah's Witnesses believe that the Bible prohibits ingesting blood and that Christians should therefore not accept blood transfusions or donate or store their own blood for transfusion...
. For religious reasons, Jehovah's Witnesses will not accept any allogeneic transfusions from a volunteer's blood donation
Blood donation
A blood donation occurs when a person voluntarily has blood drawn and used for transfusions or made into medications by a process called fractionation....
, but may accept the use of autologous blood salvaged during surgery to restore their blood volume and homeostasis during the course of an operation, although not autologous blood donated beforehand.
Bloodless options
Ways to avoid the adverse events associated with allogenic transfusion are often grouped under the umbrella term bloodless surgeryBloodless surgery
Bloodless surgery is a term that was popularized at the beginning of the 20th century by the practice of an internationally famous orthopedic surgeon, Adolf Lorenz, who was known as "the bloodless surgeon of Vienna." This expression reflected Lorenz's methods for treating patients with noninvasive...
. There are several so-called bloodless options. These include:
- Minimally invasive surgical techniques
- ErythropoietinErythropoietinErythropoietin, or its alternatives erythropoetin or erthropoyetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production...
(a hormone that stimulates peripheral stem cells in the bone marrow to produce red blood cells) - Blood substitutesBlood substitutesA blood substitute is a substance used to mimic and fulfill some functions of biological blood, usually in the oxygen-carrying sense...
such as blood volume expanders and oxygen carriers (the latter as yet unlicensed in North America) - Autologous blood donation, including pre-operative donation (suitable only for scheduled surgery in which transfusion is anticipated) and intraoperative autologous donation and blood salvage.
Intraoperative blood salvage has been used for many years, especially in cardiothoracic and vascular surgery, where blood usage has traditionally been high.
Blood salvage procedures
Several processes have been developed to assist in salvaging the patient's own whole blood in the perioperative setting. These can be categorized into three general types of salvage procedures:- Cell processors and salvage devices that wash and save red blood cells, i.e., "cell washers" or RBC-savers
- Direct transfusion
- Ultrafiltration of whole blood
Regardless of manufacturer, there are many types of cell processors. Cell processors are red cell washing devices that collect anticoagulated shed or recovered blood, wash and separate the red blood cells (RBCs) by centrifugation, and reinfuse the RBCs. RBC washing devices can help remove byproducts in salvaged blood such as activated cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
s, anaphylatoxin
Anaphylatoxin
Anaphylatoxins, or anaphylotoxins, are fragments that are produced as part of the activation of the complement system.. Complement components C3, C4 and C5 are large glycoproteins that have important functions in the immune response and host defense...
s, and other waste substances that may have been collected in the reservoir suctioned from the surgical field. However, they also remove viable platelets, clotting factors, and other [plasma proteins] essential to whole blood and homeostasis
Homeostasis
Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
. The various RBC-savers also yield RBC concentrates with different characteristics and quality.
Direct transfusion is a blood salvaging method associated with cardiopulmonary bypass (CPB) circuits or other extracorporeal circuits (ECC) that are used in surgery such as coronary artery bypass grafts (CABG), valve replacement, or surgical repair of the great vessels. Following bypass surgery the ECC circuit contains a significant volume of diluted whole blood that can be harvested in transfer bags and re-infused into patients. Residual CPB blood is fairly dilute ([Hb] = 6–9 g/dL; 60–90 g/L) compared to normal values (12–18 g/dL; 120–180 g/L) and can also contain potentially harmful contaminants such as activated cytokines, anaphylatoxins, and other waste substances that have been linked to organ edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
and organ dysfunction and need a diuretic
Diuretic
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...
to reverse.
Hemofiltration or ultrafiltration devices constitute the third major type of blood salvage appearing in operating rooms. In general, ultrafiltration devices filter the patient's anticoagulated whole blood. The filter process removes unwanted excess non-cellular plasma water, low molecular weight solutes, platelet inhibitors and some particulate matter through hemoconcentration, including activated cytokines, anaphylatoxins, and other waste substances making concentrated whole blood available for reinfusion.
Hemofilter devices return the patient's whole blood with all the blood elements and fractions including platelets, clotting factors, and plasma proteins with a substantial Hb level. Presently, the only whole blood ultrafiltration device in clinical use is the Hemobag. These devices do not totally remove potentially harmful contaminants that can be washed away by most RBC-savers. However, the contaminants that are potentially reduced by using RBC-savers, as shown by data from in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
laboratory tests, are transient and reversible in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...
with hemostatic profiles returning to baselines within hours. The key is that coagulation
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
and homeostasis are immediately improved with the return of concentrated autologous whole blood.
Over the years numerous studies have been done to compare these methods of blood salvage in terms of safety, patient outcomes, and cost effectiveness, often with equivocal or contradictory results.