Blood Exchange Protocol in Child’s Surgery Helps Prevent Complications
A child with erythropoietic protoporphyria (EPP) — marked by skin hypersensitivity to sunlight and sometimes artificial light — underwent cardiac surgery with minimal issues due to a blood exchange protocol that prevented photosensitivity effects and potential hemolysis, or the destruction of red blood cells, according to a recent case report.
“During any operation involving cardiopulmonary bypass, blood flows through tubing outside the body and hence is extensively exposed to operating theatre lights. This places EPP patients at a risk of severe [surgical] and post-operative haemolysis in addition to the risk of skin photosensitivity,” the researchers wrote, further noting, “In our patient, this risk was greatly reduced via an [blood] exchange transfusion.”
The study, “Cardiopulmonary bypass in a child with erythropoietic protoporphyria,” was published in the Australasian Journal of Dermatology.
EPP is an inherited dermatological condition resulting from a mutation in the FECH gene, which codes for the enzyme ferrochelatase. That enzyme is a key component of the pathway to convert protoporphyrin into heme — an integral part of hemoglobin, which transports oxygen throughout the body in the bloodstream.
Due to this deficiency, patients with EPP have a buildup of protoporphyrin and porphyrin in the skin, liver, and red blood cells. In the skin, protoporphyrin absorbs light and creates reactive oxygen species — molecules that are extra reactive and can ultimately lead to cell damage.
In patients with EPP, these reactive oxygen species can lead to tissue injury and cause patients to have painful skin photosensitivity, which is extreme sensitivity to light. This photosensitivity mostly occurs along the visible light spectrum, which includes artificial lights and UVA, the ultraviolet waves present in sunlight.
Given this, people with EPP need to avoid unnecessary exposure to sunlight, wear protective clothing, and use broad-spectrum sunscreens that protect against UVA rays.
The buildup of protoporphyrins in the liver and blood is not usually a considerable issue because those tissues are not exposed to light. However, during surgical procedures, the operating room lights can trigger hemolytic anemia, or a lack of oxygen to tissues due to red blood cell destruction, potentially damaging internal organs. Additionally, blood loss can trigger new red blood cell production and increase porphyrin levels.
Moreover, during surgeries in which a cardiac bypass is needed, blood flows through clear tubing, exposing the blood to the bright operating room lights and potentially resulting in hemolysis complications.
This new case report follows a 4-year-old boy with EPP who required cardiac bypass for an operation to repair a ventricular septal defect. With this birth defect, there is a hole in the separation between the chambers of the heart.
The boy had several episodes of painful skin reddening, called erythema, and swelling after sun exposure, beginning at age 2. At around age 3, he was found to have mutations on both copies — one is inherited from each parent — of the FECH gene. Both mutations have been associated with EPP and reduced ferrochelatase enzyme production.
His total red cell porphyrin at the time of diagnosis was 32 micromoles per liter (mcmol/L; less than 2 mcmol/L is the normal value), and he also was found to have iron-deficiency anemia. His EPP was mostly managed with good sun protection and his episodes of painful photosensitivity decreased.
Both the hematology and dermatology teams were consulted prior to the surgery to help manage his EPP during the procedure.
His anesthetic medications for the surgery included sevoflurane, fentanyl, dexmedetomidine, tranexamic acid, and pancuronium — medications typically used during surgery for sedation, pain relief, bleeding control, and muscle relaxation.
In an effort to manage his EPP, the clinicians chose to prime his bypass machine with blood and perform an exchange transfusion during the surgery.
“In consultation between the surgical and dermatology teams, the decision was made to begin the heart repair with an exchange transfusion, replacing the protoporphyrin loaded blood cells with normal blood cells,” the researchers wrote.
The patient’s blood volume was calculated to be 1,460 milliliters, and a two-thirds exchange transfusion was conducted, during which 970 milliliters (about two-thirds of the total) were removed and replaced with donor red blood cells and plasma. The blood removal was done via a cell saver — a special machine that can save lost blood if it is needed later on in surgery.
The surgery for the septal defect was uncomplicated, and the patient came off of bypass without incident. No hemolysis was observed during surgery.
There was some residual bleeding post-bypass with an indication of an underlying coagulopathy — a disturbance of normal blood functioning resulting in either excessive bleeding or clotting.
After anesthesia was induced and immediately prior to surgery, the patient’s total red cell porphyrin level was 40 mcmol/L. Following the exchange transfusion and at the end of surgery, the level was 12 mcmol/L, a reduction to one-third of his levels. Meanwhile, hemoglobin was 9.2 g/dL prior to the surgery, 10.6 g/dL 15 minutes after starting the bypass exchange, and 11.3 g/dL on the first day after surgery without any post-surgery transfusion needed.
Additional measures to safeguard the patient were taken during his surgery, including adjusting the wavelength of the operating room lights to favor higher wavelength visible light that would cause fewer issues for the patient. Additionally, the clear tubing of the bypass machine was partially draped with opaque sheeting to prevent exposure of the blood to light.
During recovery, the boy was kept in low light and low ultraviolet settings. He was discharged from the intensive care unit on the first day after surgery, and went home on the fourth day after the procedure. Ten days after surgery, he seemed to be recovering well.
“This is the first reported case of EPP being successfully managed with an exchange transfusion in the setting of cardiopulmonary bypass,” the researchers concluded. “The child had no post-operative complications.”