Blood Protection Method: Retrograde Autologous Prime
In order to carry out open heart surgery, the functions of the heart and lungs must be stopped and the blood inside the heart should be drained during the operation. During surgery, the functions of the heart and lungs are provided outside the body with a device called a heart lung machine (cardiopulmonary bypass). The heart lung machine is used by a perfusionist. This prosudüre is called cardiopulmonary bypass (KPB). Various configurations of the heart lung machine can be found. It mainly works on the principle that the blood taken from a central vein is passed through a perfusion circuit outside the body, collected in a reservoir, pumped and filtered after blood-gas exchange with the help of oxygenator and returned to the body with the help of arterial system to ensure the circulation of other tissues and organs. The main components of a heart lung machine are the pump (artificial heart), oxygenator (artificial lung), venous reservoir, arterial and venous cannulas, connection lines, arterial filter and heat exchanger. Before starting KPB, the lines between the patient and the pump are filled with oxygenator and venous reservoir starter solution, creating a closed circulatory system with no air that can create embolism. This initial solution, which has a near-normal pH value that fills arterial and venous lines and allows the removal of air, and whose ion content resembles plasma, is called a prime solution. Previously prepared using high volume donor blood, starting solutions are preferred from blood poor except for severe anemias, as they cause complications such as fluid loading, capillary obstruction, tissue perfusion disorders, convulsions, stroke, pump lung in the postoperative period. In the adult patient, the prime solution, which is about 1650 ml, is mixed into the circulation and this solution provides normovolemic hemodilation. Prime, balanced electrolyte solutions that provide hemodilution. Crystalloid and colloid fluids are used for hemodilution.
The most important problems we encounter in standard KPB applications are bleeding due to systemic heparinization, high blood transfusion rates and hemodilution due to prime process.
Hemodilution leads to a decrease in the shaped elements of the blood, especially erythrocytes, and due to hemodilital anemia, the O2 carrying capacity of the blood decreases, resulting in the need for blood transfusion.
Blood transfusions can cause hemolytic, allergic, febrile reactions, risk infecting infectious diseases such as hepatitis, cytomegalovirus (CMV) and human immunodeficieny virus (HIV), but the association with immunosuppression and transfusion is acute lung injury syndrome (Transfusion-related acute lung injury); TRALI) as well as early and late complications, as well as known and as yet unknown side effects. In addition, the use of blood and blood products increases hospital costs.
In studies, hemodilative anemia has been shown to have a negative effect in terms of organ functions and cognitive functions. It is known that the minimum level of hematocrit that must be in order to ensure adequate oxygen delivery is around 20%. It has been reported that low hematocrit value causes tissue hypoxia, causing negative effects such as hyperlactemia. In addition, with the onset of KPB, hemodilution caused by the initial solution can cause tissue edema due to colloid osmotic pressure. Tissue edema can be seen in myocardia as well as in many organs and myocardical damage can be improved.
Clinically, the most pronounced effect of hemodilation is the decrease in perfusion pressure at the onset of KPB. Due to the non-physiological conditions of KPB, it is reported that it affects some organ functions besides tissue edema, especially due to fluid escape to the extravascular area. In particular, the lung is very affected by this edema fluid and causes respiratory dysfunction after surgery.
Hemodilution also causes a 30-35% reduction in the total platelet count and causes bleeding problems observed in cardiac surgery.
Homologous blood transfusion is frequently used in open heart surgery to protect against the undesirable effects of hemolystial anemia. Stating the various harmful effects of blood transfusions suggests that autologous blood should be used and patient blood should be better evaluated. In recent years, a number of blood protective techniques have been introduced as clinics in order to get rid of the increasing knowledge and undesirable effects of blood transfusion and hemolytic anemia. These applications can be summarized as acute normovolemic hemodilation (ANH), cell saver, retrograde autologous prime (ROP), mini cardioplegia, hemofiltration, use of minimal circulatory systems, heparin coated systems, venous vacuum drainage systems.
One of these methods, ROP method, is to empty the prime solution into a bag in the amount allowed by hemodynamic parameters before starting KPB, filling the lines with the patient’s own blood and trying to reduce the hemodiluation by reducing the prime solution to the minimum possible level. With ROP application, it is aimed to examine hemoglobin, hematocrit values and effects on blood and blood product transfusion in intraoperative and postoperative periods with this study.
Prime Solutions
In the perfusion circuit, it is mandatory to use a minimum prime solution that will fill the system, provide sufficient current and do not cause air embolism. Prime solutions cause hemodilution and affect hematocrit values.
Full blood was used as the prime solution with the idea that KPB would be more physiological in its initial times. Excessive blood use increased the cost of heart surgery, requiring significant blood bank support. With the use of high amounts of blood, the likelihood of infection and viral diseases was also increasing. The use of blood as a prime solution has been abandoned because many organ dysfunctions, especially pulmonary functions, have been seen. The first use of non-blood prime solution was expressed by Nepture and Panico in 1959, and since then, the use of crystalloid and plasma expander colloid fluid as a prime solution has increased and blood use has decreased. The important thing in the selection of prime solution is that the osmolarity of the selected fluids is close to human serum osmosis and does not disturb the distribution of fluids and electrolytes of the body. 60% of the total body mass in men and 50% in women consists of water. 40% of total body water is intracelar, 20% is in the extravalular area, 15% of the extravalular fluid is in the interstitial and 5% is located in the intravascular region.
When water passes directly through the cell membrane without the need for energy, the movements of the water are determined by the osmolarity of the environment. This osmolarity, which is important in the mobility of water between compartments, consists of the sum of the molecular numbers of all substances dissolved in water and the amount of substance dissolved in one liter of water is called osmolarity. Apart from the shaped elements of the blood, the rest is expressed as plasma and 93% of the plasma consists of water and 7% consists of proteins and lipids.
Crystalloid Fluids
Compounds created by decomposition of certain small molecules such as Na+ (23 Dalton), K+ (39.1 Dalton), C1- (35.5 Dalton) and dextrose (180 Dalton) are called crystalloid solutions.
Crystalloids are simple volume-enhancing solutions that spread rapidly between compartments, are close to plasma electrolyte quantities, human plasma electrolytes, viral disease transmission, allergic and no side effects risks, low cost and easily available volume enhancer solutions.
The most preferred crystalloids are liquids with a pH of 7.4, calcium and dextrose, and no need for additional sodium bicarbonate. Solutions with dextrose can increase the risk of intraoperative hyperglycemia. Hyperglycemia also increases lactate accumulation in target organs, which reduces intracellar pH, having a negative effect on neurological outcomes. In the use of calcium-containing liquids, it is reported that thrombus may occur in the cannulas and lines, and additional anticoagulan can be used to prevent this.
The reason why crystalloids are preferred as prime solution is that they are easy to breakthrough with the use of diuretics.
When only crystalloid fluids are used without the use of colloid fluids in the prime solution, plasma can cause oncotic pressure to decrease, which can cause tissue edema in various organs, including myocardial.
Crystalloid fluids are divided into three solutions as isotonic, hypotonic, hypertonic solutions. Solutions close to osmolarity human serum osmolarity are called isotonic solutions, osmolarity is called solutions lower than human serum osmolarity, hypotonic solutions, osmolarity is higher than human serum osmolarity and solutions with higher osmolarity than human serum osmolarity are called hypertonic solutions.
Lactate Ringer and Isolyt S solutions used as prime solutions are balanced crystalloid solutions. They have a neutral pH. They contain electrolytes at rates similar to the electrolyte ion value in human plasma.
Lactate Ringer is the most physiological fluid in light hypotonic and electrolyte content. In 1880, a ringer solution was created by Sydney Ringer, and in 1930 Alexis Hartmann added lactate to the ringer solution and named it The Lactate Ringer (Hartmann solution).
In terms of electrolyte content and osmolarity, ringer lactate (RL) solution appears to be the closest to plasma. Lactate-containing solutions should be used carefully as lactate can turn into glucose by glycogenic means in diabetic patients. Lactate is used as a source of bicarbonate in lactate ringer solution. Lactate in lactate Ringer turns into bicarbonate in the liver, which is effective in preventing the formation of metabolic acidosis and in the treatment of existing metabolic acidosis.
Instead of lactate, which is used as a source of bicarbonate in lactate ringer solution, isolayt S solution has acetate and gluconate. Mg myocardia in the content of Isolayt S has an important role in adenosine triphosphate (ATP) methodbolism and intracellar energy.
The 5% dextrose solution contains 50g/L dextrose and has 250 mOsm/L osmalirite. 5% Sugar in the solution of dextrose in water is rapidly metabolized. Insulin is used to prevent hypoglycemia in diabetic patients who should be used.
In prime solution, bicarbonate is used as a buffer, mannitol (3mg/kg) as a kidney protector and heparin as anticoagulan.
Colloid Fluids
Compounds consisting of waterborne solutions of large molecules such as albumin (69000 Dalton) and dexstran (70000 Dalton) are called colloid solutions. Colloid solutions; they can replace plasma, perform some of the tasks of plasma proteins. Since the most important of these functions is the liquid binding capacity called colloid osmotic pressure (KOB) pressure, these solutions are also called plasma extenders. Colloid solutions have less properties of passing through the capillary and glomerular membrane than crystalloid solutions. The colloid osmotic activities of the high molecular weight substances contained in their contents ensure that these solutions remain in the vein. The majority intravascular half-life of colloid solutions varies between 3-6 hours.
An ideal colloid solution should have an appropriate colloid osmotic pressure and should only remain in the intravascular area, have a long half-life and cost-appropriate, have a long shelf life and have no special storage conditions, be free of toxic substances, have no side effects, do not cause infection, should not affect organ functions and immune functions.
Colloid solutions are divided into natural colloids and artificial colloids.
Natural Colloid Fluids
Plasma protein fraction (PPF), human serum albumin (HSA), fresh frozen plasma (TDP) are natural colloids. Natural colloids are expensive, costly and hard to supply.
Plasma Protein Fraction (PPF)
After the precipitation of human plasma with cold ethanol, it is prepared by pasteurization. It is found in 15% globulin with 85% albumin in its content. Its effects and the way it is used are similar to albumin. due to the cause of precalcinac activator in the cericon and its allergic structure, it can cause excessive hypotension and out-of-vein exit. It is found in 4-5% solutions.
Human Serum Albumini (HSA)
It is a volume-enhancing protein obtained by gradual fractionation of large amounts of plasma and pasteurization of the end product. It’s derived from human plasma or plesenta. It has a half-life and 17 m/g water binding capacity between 10 and 15 hours and is available in various solutions of 5%, 20%, 25%. The oncotic pressure of the 5% album (50 g/L) is 20 mmHg, while its oncotic effect is approximately 12-18 hours. The oncotic pressure of the 25% album (250g/L) is 70 mmHg and can extend the plasma volume by 4-5 times the infused volume. In hypovolemia, 25% albumin should not be used for volume replacement purposes as it draws fluid from the intersitisal area. In case of hypoproteinemia, it is used for the transfer of fluid from the intersitisal area to the vascular area. When used by adding to the prime solution, it delays platelet activation by covering the surfaces in the perfusion system with a protein layer. It should be used with caution as it can lead to pulmonary payment by sudden expansion of the intravenous volume. It can cause allergic and anaphylactic reactions and infectious infections such as hepatitis and HIV, and its production is costly.
Fresh frozen plasma (TDP)
The rest of the blood is called plasma immediately after it is taken or after the cooling centrifuge of the shaped elements in it by waiting for a maximum of 6 hours between +2 and +6 degrees. It is called fresh frozen plasma, frozen with shock or dry ice within a few hours. It can be stored for 24 months below -40 degrees, – 12 months at 30 degrees, 6 months at -25 degrees and 3 months at -18 degrees. Dissolution is carried out in 30-37 °C water in approximately 15-20 minutes. It should be used immediately after thawing and should not be frozen again. It contains normal levels of clotting factors, 400-800 mg fibrinogen, 100-300U factor 8. It is used to eliminate the inadequacy of clotting factors and to replace plasma losses due to burns and bleeding. Cross match is not required and is used based on ABO compliance, there is a risk of hepatitis B, HCV and HIV infection. The daily usage amount varies between 12-15 ml/kg (2-4 packs).
Artificial Colloids
Dexstrate solutions are starch solutions and gelatin preparations. They are easy to obtain and have volume-expanding effects as much as natural colloids. They do not carry the risk of infection, they are inexpensive, there is no significant difference between them and natural colloids in terms of side effects. For these reasons, artificial colloids are preferred more than natural colloids in cases where volume treatment and hemodilation are required.
Dexstrate Solutions
It is a solution obtained by hydrolysis of high molecular weight natural polysaccharides and has a water binding capacity of 20-25 ml/g and an oncotic pressure of 40 mmHg and its main ingredient is sugar beet. The two most commonly used varieties are Dextran 70 (Makrodex MA 70000, Pharmacist Baxter, Istanbul, Turkey) 6% and dextran 40 (Rheomacrodex MA 40000, Pharmacist Baxter, Istanbul, Turkey) 10%.
It is stored by amylase in the blood and its destruction is ensured. Dextran 70 is more preferred in the treatment of volume replacement due to its long effectiveness (semi-foreground 12 hours). Dextran 40 reduces blood vizcosity and improves microcirculation. Dextrans significantly lower antithrombin3 and fibrinogen levels due to antiplatelet effects and impair platelet function. If it exceeds the dose of 1.5 g/kg per day, it increases the tendency to bleed, and when given above 20 ml/kg per day, it leads to prolonged bleeding time and impaired kidney function. Dextrans have antigenic properties.
Starch Solutions
Hydroxide starch (HES) is its main ingredient in corn starch, obtained from amylopeectin in corn starch by hydroxide subcitusion. There are varieties such as low (130,000 D), medium-low (200,000 D) and high (450,000 D) according to molecular weights. Hespan (Hetastarch, Novaplus, USA) are high molecular weight, Heas Sterile (Pentastarch) medium-low molecular weight, Voluven (Tetrastach, Fresenus, Deutschland) are low molecular weight solutions.
Molecular weight (Mw) is important in determining the colloid osmotic strength, pharmacokinetics, alumulation and periphrbic effects of HES in tissue and plasma (on coagulation and kidney function). The halving life of the hespan (Hetastarch) high molecular weight solution is approximately 10-12 hours, the volume extender effect time is between 6-8 hours and is used as a long-term volume replacement. The halving life of the Heas Sterile (Pentastach) medium-low molecular weight solution is approximately 3 hours, the volume expander effect time is between 4 hours and is used as a medium-term volume replacement. The volume-expanding effect time of the voluven (Tetrastach) low molecular weight solution is about 4 hours and its use is mostly preferred in the treatment of hypovolemia and shock.
HES is an effective and inexpensive volume extender. The incidence of allergic reactions is less than in the preparations of dextran solutions and gelatin. Nausea, vomiting, fever, chills, skin rash, long-term and persistent itching can be seen as side effects.
Gelatin Preparations
Using the bone and collagen tissues of large head animals as the main substance, the hydrolysis process of collagen is obtained. There are 2 types of modified liquid gelatin (3% Gelefusine, Braun, Melsungen, Germany), Polygel (3.5% Haemaccel, Dem, Kadikoy, Istanbul).
Gelatin preparations are used as hypovolemia, shock therapy, intraoperative hemodilation and prime fluid. They are excreted through a large amount of kidneys, and their effects are as short as 2-3 hours, as their excretion occurs quickly because their molecular weight is low. They show a mild diuretic effect and increase the specific weight of urine. When given in large volumes, they cause insufficient clot formation. Because they are of animal origin, they can cause creutzfeldt-jacob disease (Mad calf disease) and Bovine Spongioform Encephalitis (BSE).
Mechanical Methods To Reduce Blood Use in Cardiopulmonary Bypass
Acute Normovolemic Hemodilution
Acute normovolemic hemodilation is a form of autotransfusion developed to avoid blood transfusion or to minimize the amount of transfusion, which involves taking and storing the patient’s own blood after induction and giving it back to the same patient in the perioperative period.
It is based on the principle of rectating the volume with solutions such as crystalloids or colloids and returning the blood taken to the patient when necessary, while blood is taken from a peripheral thick vein, central catheter or artery to bags containing anticoagulants (CPDA -1) immediately after anesthesia induction. Peripheral oxygen saturation, blood pressure, heart rate and electrocardiogram (ECG), central venous pressure measurement (CVP) parameters should be monitored during the procedure.
Acute normovolemic hemodilation is applied by taking 1500-2000 ml or 10-15 ml/kg of blood in patients with a hematocrit value of 36% and hemoglobin levels above 12 gr/dl. The amount of blood to be taken varies depending on the targeted degree of hemodthil and the level of hematocrit.
For 1 ml of blood taken during the removal of autologous blood, 1 ml of colloid and 0.5-1 ml crystalloid solution should be given and the excretion of crystalloid and colloid solutions given by applying furosemid at a dose of 0.15-1 mg/kg 5-15 minutes before the return of the removed autologous blood to the patient should be ensured.
If the bagged blood is to be given before 6 hours, it should be stored at room temperature to maintain platelet functions, and cooled if it will take more than 6 hours to give.
Decrease in homologous blood transfusion of acute normovolemic hemodilation, reduction in postoperative blood loss, increasing tissue perfusion and oxygen delivery to tissue, low cost, no extra time, absence of transfusion-related diseases, lack of hemolithic, allergic reactions, ease of application, availability of ready-made blood in case of excessive bleeding and negative effects of KPB as well as disadvantages such as additional monitoring, equipment and personnel requirements and deterioration of anemia and hemodynamic parameters depending on the amount taken.
Ultrafiltration
Ultrafiltrators are devices consisting of micro-perforated precipitated fibers (0.3-0.4 μ) that are added to the KPB circuit, removing excess fluid by removing the excess fluid from the arterial end and filtering it out by throwing it towards the venous end.
Ultrafiltration provides liquid transport by applying pressure as the basis. During this fluid transport, water, electrolytes and small molecules are transferred to the other side by applying hydrostatic pressure on a semi-permeable membrane, while the passage of large molecules such as blood cells and plasma proteins is prevented.
The aim of ultrafiltration is to eliminate the volume load caused by the addition of the initial volume to total bodily fluid during KPB and increased capillary permeability due to the inflammatory response, to maintain concentration, to increase blood hemoglobin levels and to reduce inflammatory response. It is a very effective and easy method of eliminating dilutional anemia that occurs during KPB and does not cause any changes in serum electrolyte concentrations or acid-base balance.
It is an inexpensive, effective and simple method that helps control volume for perfusionist. Ultrafiltration is divided into two types according to the time applied and the method used when applying it. The form of ultrafiltration applied during KPB and mostly during the warming period is called Conventional Ultrafiltration (KUF), the form of ultrafiltration applied after the termination of KPB is often applied by removing the blood from the aortic cannula, passing it through the hemocencentrantrator and giving it from the venous cannula to the right atrium.
Autotransfusion
The system of collecting blood, washing, processing and returning it to the patient with serum physiological method by applying aspiration method with autotransfusion (cell saver) device is called autotansfusion. One of the most important complications of open heart surgery with autotransfusion method, blood lost by bleeding can be replaced, homologous blood use decreases and hematocrit levels increase.
Anticoagulation is provided before systemic heparinization and after protamine neutralization by aspirating blood with double lumen aspirator tubing system and often mixed with anticoagulants, which are heparinized isotonic. Anticoagulated blood is filtered and pumped from the autotransfusion reservoir into a centrifugal latham pool, where it is separated from its cellular components to separate erythrocytes from plasma. The decomposed erythrocytes are washed with saline solution, reducing activated leukocytes, fibrin demolition products, inflammatory agents and tissue particles and removing heparin. The resulting erythrocytes are sent to the blood bag for re-infusion and the autotransfusion process is completed and the process is repeated for the blood coming into the reservoir. During the process, washing speeds, high washing speeds (>600 ml/min) can cause erythrocytes to break down and disperse, while low washing speeds (<200 ml/min) can cause insufficient cleaning of residues.
Although damaged erythrocytes and other tissue particles are largely cleaned by washing with autotransfusion system, infection agents and tumor cells are not suitable for use in infected and oncological patients because they cannot be completely destroyed. It is thought to pose a risk of postoperative bleeding and infection due to the fact that it also washes away plasma proteins, platelets and leukocytes from the blood. It is also a costly system due to the use of special sets and systems.
Venous Vacuum Drainage System
Venous vacuum drainage is a simple and effective system used to achieve sufficient current by increasing venous drainage with the help of vacuum in cases where venous rotation is not sufficient due to the effect of gravity during KPB. The main purpose is to increase venous rotation by vacuuming into the venous reservoir and not to use additional mai or blood products. In order to reduce the risk of microemboly and blood trauma, low vacuum should be applied below -30 mmHg as much as possible (55). Before starting vacuum-assisted venous drainage, the free air outlet part of the oxygenator must be closed and no open sections should be left in the reservoir to leak vacuums. When venous vacuum drainage is terminated, the free air outlet of the oxygenator should be opened, preventing the air entering the oxygenator from becoming trapped, causing massive air embolism.
The advantages of venous vacuum drainage method by increasing venous rotation, to relieve the surgical site and to reach sufficient current, to enable the use of fine venous lines and small venous cannulas, to reduce blood use by preventing additional mai requirement and hemodilution, microembolym possibility and to increase the risk of blood trauma can also be listed as disadvantages.
Mini Cardioplegie (Microplegia)
All solutions developed to quickly stop the heart at the diastolic stage during KPB and protect the myocardia against ischemia and reperfusion damage that develop in the heart after arrest are called cardioplegi solutions. Although the application of cardiopegia solutions is different in heat, methods and contents, they are generally divided into three types: crystalloid, crystalloid and blood mixture and blood cardioplegia only. Microbes are a 1/4 crystalloid-blood mixture or a method of giving cardioplegie using the patient’s own blood without using crystalloid cardioplegia. Thus, the hemodilution created using crystalloid cardioplegia decreases and the amount of blood and blood products used to prevent hemodilutional anemia decreases.
If blood cardioplegia is to be used, its contents can be given by adding oxygen to the blood taken from the pump. In the case of 1/4 blood cardioplegie, blood and crystalloid cardioplegie taken directly from the oxygenator can be passed through a separate roller pump and the roles can be mixed after the pump and heat, pressure and current can be controlled. In cases where blood cardioplegia is intended to be given as a low dose, it is possible that the contents of K+ and Mg in the injector can be added to the blood via the perfusion pump and given in a current and pressure controlled after a role is passed through the pump.
Although the amounts of drugs applied to cardioplegic solutions may vary according to clinics, the K+ ratio is usually set at 30 mEq/lt in the first dose cardioplegi, while in repeat doses at intervals of 20 minutes it can decrease to 10-15 mEq/lt.
Heparin Coated Systems
During or after KPB, together with anticoagulation created to prevent clotting during KPB; Bleeding, pulmonary edema, neurological changes and multiorgan damage can be seen as a result of the deterioration of the hemostatic mechanism with the contact of the blood with the foreign surface. During the studies to reduce contraindications caused by KPB, it was seen that heparin-like molecules (heparan sulfate) were present on the luminal surface of microvascular endothelium along with biological active substances and it was considered to heparin cover the surfaces of KPB systems. It is reported that heparin coated system (HKS) can reduce the amount of bleeding and the negative effects of KPB on erythrocytes with low dose systemic heparinization method (1.5 mg/kg) and low ACT values.
Mini Roaming Systems
Mini circulatory systems are minimalized, closed system perfusion circuits with shorter tubing systems than standard perfusion circuits, which do not contain cardiotomy reservoirs. Since it is a closed system, autotransfusion system is used as aspirator and santrifugal pump is used as pump head. There is a drip chamber for volume control and vent line connection. During perfusion, air entering the system and removing the air entering the system can cause problems due to the fact that there is no venous reservoir in minimal circuits, which are closed systems. There is a bubble detector for air control and a venous bubble trap for removing the collected air. Cardioplegie is given as normotermic mini blood cardioplegia from the perfusion system. Half a dose of heparinization (150 IU/kg) is performed before KPB and the ACT value is studied to be kept between 250 and 300 seconds during KPB. The amount of prime is no more than 900 ml. Hemoglobin and hemocarditis values were reported to be higher with decreased hemodilation and less use of blood and blood products. It is also stated that platelet functions are better protected and the amount of postoperative drainage is less than open systems due to lack of blood air contact. Among other methods of preventing blood use, it is a costly system due to the fact that it requires extra sets and equipment.
Retrograde Autologous Prime (ROP)
Before starting KPB, the ROP method is a method that tries to reduce the primary solution to my minumum by filling the perfusion system with the patient’s own blood, limiting hemodilution, reducing hemodilutional anemia, reducing blood use and/or preventing it.
With the onset of KPB, mandatory hemodilution occurs due to pump prime solution. In heart surgery patients, this hemodilation and the hemodilial anemia it creates pose a great risk for blood transfusion. The ROP method uses the patient’s own blood as the pump starter solution. In order to apply the ROP method, a line is added to the perfusion system before KPB starts, the prime solution is taken to a bag connected to this line and the system is filled with the patient’s own blood in the amount allowed by hemodinami. Thus, the prime solution is reduced to the minimum possible level and the dilution due to the prime solution is tried to be prevented before it occurs. It is reported that hemodilial anemia caused by the onset of ROP method can be prevented and blood transfusion can decrease significantly.
ROP is a very low-cost application proposed by Panico and Neptune in 1959, which is a modification of the method of using the external initial solution of bank blood. It was first described by Rosengart and his friends in 1998.
Previously, in patients with preoperative anemia and risk factors such as small body surface area, hematocrit was increased by reducing hemodilution with ROP application, blood transfusion was reduced during KPB and intraoperative period, and then recommended for all open heart surgery patients.
Before starting the ROP process, a system is placed in the perfusion circuit that will allow the bagging of the prime solution.
ROP process is started immediately after the patient is fully hypnified and cannuced and all preparations for KPB are completed and immediately before the transition to KPB in order to start the KPB immediately as soon as there is a deterioration in the hemododymide during the procedure.
The goal is to make sure that you Since reducing the amount of prime solution to a minimum level and increasing the amount of the bagged solution to reduce or prevent hemodilusion caused by the prime solution, the bagging process should be continued in the amount that hemodynamic parameters allows.
As with all stages of KPB during the procedure, monitoring monitoring and cooperation with the anesthesiology team are of great importance. Arterial blood pressure, peripheral O2 saturation, electrocardiography (ECG), central venous pressure (CVP); pulmonary artery pressure (PAP) and cerebral oxygen saturation (NIRS) parameters should be continuously monitored. During ROP, systolic artery pressure should not be allowed to fall below 80 mmHg, patients should be placed in a 30 degree upside position and vasocornrüktur should be supported with drugs. If there is deterioration and decrease in arterial blood pressure in any of the following parameters, the process should be terminated and KPB should be started immediately.
ROP should be applied gradually in about 5-8 minutes. Since the procedure can cause sudden deterioration of hemoddinamide when performed quickly, it may be necessary to terminate it before it reaches its goal and start perfusion immediately. The process begins from the arterial line before. By opening the clingfilm of the prime bagging line, the prime solution in the arterial line and arterial filter is gradually bagged by drainage under the influence of gravity, filling the line with the patient’s blood and closing the clamp after the line is filled with patient blood.
Then the prime solution of the venous line is bagged. During bagging, the clamp placed on the venous line is gradually opened at regular intervals and the prime solution is directed to the bag with the effect of gravity. Depending on the preference of the perfusionist, this section can be done in the form of direct orientation to the bag or in the reservoir and from there to the bag. By not opening the clamp suddenly, the patient’s sudden volume loss and hemodynamic parameters are tried to be prevented. After the venous line is filled with patient blood, the clamps of the bagging line and venous line are closed.
Finally, the primary solution of the reservoir, pump turn headline and oxygenator is bagged, respectively. Before starting the procedure, clamping is placed on the arterial line and when the pump head starts to rotate, the prime solution is prevented from going to the arterial line and the patient. The venous line is opened intermittently and patient blood is directed from the venous line to the reservoir, during which the pump head is rotated so as not to create pressure within the perfusion system and sent to the prime bag in the reservoir. The bagging process of these sections can also be performed by opening the shunt between the venous reservoir and the arterial filter outside the venous line and transferring patient blood from the arterial line to the venous reservoir, depending on the preference of the perfusionist. After the prime bagging process of these sections is completed, the clamps of the venous line and prime bagging line are closed and the clamp placed on the arterial line is removed. After all the procedures are completed, the perfusion begins.
After the perfusion is terminated, the process in which the bagged prime solution is re-given to the system and sent to the patient, and the patient blood is not left in the oxygenator and tubing set, is called Antegrade Autolog prime (AOP). AOP procedure can be performed by giving the patient’s blood from the aortic cannula after the air check after perfusion or by giving it from the venous cannula to the right atrium.
ROP application does not require additional intervention to the patient, can be performed at very low costs and in very short periods of time, prevents mandatory hemodilution due to prime solution, reduces and/or reduces blood transfusion to minumumum, reduces and/or prevents the passage of transfusion-related diseases and can be easily applied.
Besides the advantages of KPB, which has an important place in cardiac surgery, it is the subject of various studies due to its complications. Among the most discussed topics are the hemodilution, amount of prime solution, blood transfusions and complications caused by the start of KPB and prime solution. Blood transfusions bring complications in cardiac surgery, where blood use is higher than other surgeries. Blood transfusions can cause respiratory complications, an increase in bacterial infections and allergic transfusion reactions, as well as cost high costs. For this reason, blood transfusion should be avoided as much as possible and applied in cases where the benefit is much superior to the damage that may occur.
However, severe preoperative anemia also involves risks that may affect the outcome of the operation. Wound infections, impaired renal and pulmonary functions, prolongation and increased mortality during intensive care and hospital stay are complications that can be seen as a result of preoperative anemia. In large-scale observational studies, a direct correlation between hematocrit values and hemodthial effect and perioperative morbidity and mortality during KPB was determined. With the effect of hemodiglution, O2 presentation to the tissue decreases. In anemia, the Hb level can be created that can deliver sufficient levels of O2 to the target tissue. This level may vary depending on the patient, age and additional pathologies. The permitted anemia limits are 8gr/100 ml over the age of 70 and 7gr/100 ml under 70 years of age.
Bank blood can transmit infection even if routine serological tests are carried out and they are undergone various process stages to prevent the risk of infection. Although serological tests before giving blood from 3,000 donors were negative, subsequent post-transfusion PRC tests revealed positive hepatitis B in 2 patients and hepatitis C in 24 patients, Schootstedt and his colleagues reported.
Chikvem and his colleagues identified 364 healthy blood donors as 14.9% hepatitis B, 5.8% HIV-1 and 4.1% Plasmodium Falciparum seropositive in their studies. The results of both studies suggest how rigorously blood use can be treated in the canus.
The risks posed by homologous blood transfusion have encouraged researchers to develop cheap, reliable and methods to reduce blood use. The use of methods to prevent blood loss and use significantly reduces the need for blood transfusion.
In order to prevent the risks it poses in open heart surgery and to provide a more reliable operation, the use of blood and blood products is tried to be minimized by various methods as clinics. The basis of this study was based on researching the effects of ROP application on Hb, HCT rates and blood and blood products use compared to standard prime solution use.
Many blood protection methods reduce blood use but can cause high costs as they require extra equipment. Some require high costs, some of them have possible complications, others require long periods of time, so they are not always available everywhere.
The ANH method applied as an intraoperative blood protection system has disadvantages such as deterioration in anemia and hemodynamic parameters depending on the amount taken, and the venous vacuum drainage system can increase the risk of microemboly and blood trauma.
Another of the blood protection methods is the use of cell saver. One of the disadvantages of the cell saver method is that it cannot be used in every operation due to its high price for routine use, and another disadvantage is that it is thought to pose a risk of postoperative bleeding and infection due to the fact that it removes plasma proteins, platelets and leukocytes from the blood by washing them.
Ultrafiltration system is a method used to draw excess fluid. Since the correction of the resulting hemodiluation is slow, time is required. In addition, since it creates a shunt in the extracorporeal system, it requires an increase in arterial pump flow. It is a method that brings extra costs and tries to block dilution after it has occurred.
mini circulatory systems and heparin-coated systems, which are other traoperative blood protection methods, are also not always available in every clinic due to the fact that they are quite costly for routine use.
The ROP method, which is one of the blood protection techniques that reduces transfusion and can be applied routinely in open heart surgeries, is highly reliable, low cost, does not require additional personnel and high technological equipment in its implementation, does not have serious side effects for the patient and does not require extra intervention to the patient, does not cause time loss by performing in very short periods of time, not after the formation of dilution, it is a simple and easy to apply method.
Rosengart and his colleagues administered an average of 880±150 ml of ROP in the 30-person ROP group in their study, which included 60 patients. They found the lowest hematocrit value in the ROP group as 22±3% and in the control group as 20±3%. They reported that hemodilation and the number of patients requiring transfusion decreased in the ROP group, that ROP was a safe and effective method, and that interest in ROP method increased after their studies.
As a result of their study involving 60 patients, Srinivas and his colleagues found that the lowest hematocrit value in 30 disease ROP groups was 39.5% and in the control group it was 27.03%, and found that ROP significantly reduced the need for bank blood.
In their study involving 120 patients, Hou X and his colleagues found that 83.3% of control group patients and 26.7% of patients in the ROP group needed transfusion and the overall transfusion rate of the ROP group was significantly lower.
Vandewielea and her colleagues included a total of 753 patients in their study. They administered an average of 475ml of ROP to 498 of the patients. As a result of their studies, they reported that ROP application is an effective help in dealing with the negative clinical effects of KPB-related hemodilation and hemodilism and reducing blood transfusion rate.
He and his colleagues included 100 patients who underwent open heart surgery. The ROP group administered an average of 782ml ROP to 50 patients. The lowest hematocrit value in the ROP group was 26%, while in the control group it was 22%. In the ROP-administered group, hemoglobin reported higher hematocrit values and less dilutional anemia and blood use.
In their study of 62 patients, Ricardo and his colleagues found that hemodilation was less and blood transfusion rate was significantly lower in the group of 27 patients who underwent ROP.
There are studies that report that ROP application has positive effects in the prostoperative period.
Neurological complications are most commonly observed in the postoperative period after KPB. Impairment of cerebral oxygenation due to hemolythial anemia during the operation is an important risk factor in the development of neurological complications.
In their study of 94 patients, Hwang and his colleagues said that hemodthilization was lower, hematocrit levels and cerebral oxygenation were higher in the patient group they administered ROP, and that ROP was neurologically beneficial by increasing cerebral oxygenation. The results of these studies show us that even by applying a simple and cost-free procedure such as ROP, we can prevent neurocognitive disorders from occurring in patients by increasing the cerebral oxygenation of patients.
Eising and his colleagues included a total of 20 patients in their study. They found that the amount of extravascular lung water (EVLW) did not change in the ROP group, but increased by 21% after 2 hours in the group where they applied standard prime. Colloid osmotic pressure (COB) decreased by 55% and 41% in the ROP group when standard prime was applied during KPB. Fluid balance was found to be better (2831 ± 637 ml) and posroperative time was shorter in patients with ROP group.
There was no significant difference in postoperative time and fluid balance± but the amount of postoperative drainage was 733.40± 599.05 in the ROP group, 1207.6± 704 in the control group and significantly lower in the ROP group (p<0.05).
Murpy and his colleagues included 559 patients in their study. In their study, they found that the number of patients who had postoperative cardiac arrest in the group they administered ROP was lower and they thought ROP could have positive effects on a safe technique and postoperative outcomes.
It is stated that blood use increases the cost and methods to reduce blood use reduce the cost.
As a result of their study involving a total of 193 patients, Kearsey and his colleagues reported that hospital stays were significantly lower during the postoperative period in the group that received ROP. They said that shorter hospital stays can reduce hospital costs or improve patient safety by protecting patients from hospital-based infections.
Trapy and his colleagues divided the patients into three groups in their study. They used standard KPB and standard prime in the first group, standard KPB and ROP in the second group and mini circuit (MECC) in the third group. Cross-country clamp and KPB durations were found to be significantly lower in the third group where they used mini-circuits. Hemoglobin and hematocrit levels differed significantly between the three groups, during KPB and during the postoperative period.
As a result, they reported that ROP is a safe and cost-effective application that reduces hemodilusion and blood transfusion.
Another advantage of ROP application compared to other protective methods is that all KPB circuits can be easily modified for ROP at costs as low as zero and without causing time loss.
As a result; Intraoperative Hb, Hct levels were higher, hemodilution was lower and intraoperative and postoperative blood transfusion was lower by applying ROP procedure in a multidisciplinary approach depending on individual patient characteristics. With ROP application, it was determined that not only did the side effects and complications of blood transfusion decrease, but the amount of postoperative drainage was positively affected and significantly decreased. Therefore, we believe that ROP procedure, which we believe can be modified for ROP application and become routine application with the small touches of perfusionist friends in all open heart surgery units, is a technically easy, effective and cost-effective method with no serious side effects.
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