MedStar Bloodless asked Dr. Estioko to elaborate on some key points in his report, Redo-Cardiac Surgery Without Blood Transfusion In Adult Jehovah’s Witness Patients.
Here are his replies:
Blood flows unimpeded inside the arteries and veins which are lined by smooth surface that is biologically active and provides a friendly environment for the blood. This is disturbed when there is injury to the surface lining of the blood vessels which triggers the aggregation of platelets and formation of fibrin matrix which now traps red blood cells to form a clot that seals the bleeding site and stops bleeding. The same mechanism is involved in forming clots that can obstruct the blood flow. For example, if this occurs in the coronary artery, it can lead to heart attack.
Surgery can never be 100% bloodless; there is always some blood loss. However, the surgeon can minimize this by meticulous technique, which involves controlling bleeding sites at every step of the operation, mainly using the electrocautery. He therefore makes controlled cuts instead of making big incisions and trying to catch the bleeders later, in which case blood is lost in the process. With meticulous surgery, whatever blood is spilled in the surgical field is collected in the pericardial sac and can then be recovered by using the cardiotomy suction which returns it to the heart lung (HL) machine. The less spillage the better. If there is excessive blood loss, which is not desirable, the cell saver is needed. The cell saver suction collects the blood and processes it, which involves spinning it and concentrating it to remove the excess fluid. Too much use of the cell saver is not recommended. It gives a false since of security, instead of avoiding blood loss as a primary mission. The intervention of processing causes breakdown of the blood elements. The goal of the cell saver is to recover the red blood cells and discard the liquid portion, which contains the clotting factors.
He therefore makes controlled cuts instead of making big incisions and trying to catch the bleeders later, in which case blood is lost in the process.
The HL machine, although now much improved, is only a temporary way to support the patient’s circulation during the operation. It is not as good as the body’s normal circulation. Many heart operations require the use of the HL machine for one to two hours, which is well tolerated with few ill effects. However, if the operation last longer than four hours, and the cell saver is used because of significant blood loss, there is an increased risk and occurrence of coagulation problems and poorer outcomes.
The use of Heparin is mandatory with the HL machine, to ensure that the blood does not clot as it is circulated in the bypass system. A calculated full Heparin dose is given through a central venous line (CVP), not a peripheral IV line, which maybe unreliable. This procedure is critical. If through medical error the Heparin is not delivered centrally, it is almost sure to lead to clotting of the whole blood in the system in minutes, with immediate fatal outcome.
After the conclusion of the operation, heart perfusion is restarted by removing the aortic cross clamp. The heart now is being nourished with blood and oxygen, and is also rewarmed to get rid of the effect of the cold K cardioplegia that was used to protect the heart. The vast majority of hearts start beating right away; a few require electric shock or pacing. It takes about 10 to 20 minutes for the heart to recover, which is evaluated by direct vision and the use of the transesophageal echocardiogram (TEE), plus pressure measurements. If the surgical team determines that the heart is contracting well, the flow of the HL machine can now be gradually decreased, allowing the heart to gradually take over the work of circulation. This procedure is what we call the weaning process. During full bypass, the machine is pumping about four to five liters every minute. The bypass can now be gradually dialed down to 3 liters, 2 liters, and down to zero. The machine is discontinued when the patient is tolerating things well with good cardiac contractility and good blood pressure.
Once bypass has been completely discontinued, the surgeon rechecks the suture lines and surgical sites and controls any bleeding. Careful hemostasis is particularly important in redo-surgery, because there are more dissections due to the presence of scar tissue. At this time, the fluid and blood in the bypass circuit is gradually returned to the patient via the cannula tubings, which are still in place, so actually no blood is lost. Since there is not a lot of fluid, volume overload and accompanying stress on the heart are avoided. The drug Protamine is next given to reverse the effect of Heparin and to allow the clotting function to return to normal. We suture, legate, and cauterize bleeders, but we cannot do these with the tiny capillary oozing. Repair at the capillary level must rely on normal clotting. A good illustration of this is when one falls and has a deep abrasion of the knee. This cannot be treated by suturing; compression must be used as we wait for normal clotting to do its work.
The reversal of heparinization is not like an electrical off-switch. It takes some time, depending how the blood clotting properties have been adversely affected during surgery. The less trauma to the blood, the sooner normal clotting returns. So if there is no bleeding and the clotting function is restored, the chest can now be closed after placing a couple of drainage tubes. Postoperatively, some small amount of oozing occurs inside the chest. The resulting fluid is drained by the tubes, which allows monitoring to be sure there is no bleeding (the tubes are removed in two days). The patient now is transferred to the intensive care unit (ICU) for recovery.
Historically, the early HL machines were large, requiring large priming volumes of 3 to 5 liters, and blood was used from the outset of the surgery, as part of the priming volume. With technical improvement through the years, more efficient machines were developed so that less than a liter (800 ml) of total prime is needed, without using blood; saline and other solutions are used.
Another development in the early years of heart surgery arose because the first HL machines did not reliably maintain good perfusion. This created the need for surgeons to work fast. Thus the era of the “virtuoso surgeons” was born. These were surgeons who pioneered heart surgery, such as my friend and colleague Dr. Denton Cooley, who developed and excelled in Bloodless Surgery and began performing successful bloodless heart surgery for Jehovah’s Witnesses during the 1960’s.
The human body is wonderfully made and the circulatory system is a marvel of creation. The heart pumps about five liters (depending on the patient’s size) to perfuse the tissues of the whole body. Aside from the arteries and veins there is an enormous capillary network with intricate movements of blood and other fluids. With the use of high-powered microscopes, capillary circulation has been observed to flow and ebb in constant flux, with some channels open and others closed at any given time. The organs and tissues that are working harder at a given time (the digestive tract after eating, the muscles during exercise) require and receive more blood circulation. This shows that there is not always continuous flow even in nature. When we stop the heart lung machine, the blood in the bypass system is not actually circulating but the system is still in continuity with the circulatory system, and hence may be considered to be an extension of the patient’s circulation. The blood removed in the process of ANH before the use of the HL machine and returned to the patient at the end of the procedure may be viewed in the same way. This blood is kept in continuity with the bypass-patient circuit but is not in continuous flow. The Heparin must be reversed prior to returning the blood conserved in the ANH process. The Heparin has predominant effect of not allowing clotting, so it will be of no value to return this blood prematurely. If ANH is properly utilized, it provides two benefits: it improves coagulation and increases the patient’s hemoglobin and hematocrit to levels favorable for good recovery.
Manuel R. Estioko, MD is a Cardiac Surgeon from Los Angeles, California. He first developed an interest and involvement in Bloodless Surgery because of the very high incidence of Hepatitis C in open heart patients (18 % in New York City). At that time (late 1960’s & 1970):
In 1996, Dr. Estioko coined and popularized the term “Transfusion Free Surgery” which is the other widely used designation for Bloodless Surgery.
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