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Veno-venous
bypass
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CASE REPORT
A 23-yr-old Asian man was admitted to an outside transplant center
in fulminant hepatic failure. He was well until 2 wk prior to presentation
when he developed symptoms of nausea. vomiting and weakness which progressed
to jaundice, confusion and gastrointestinal bleeding. At the time of presentation
to the transplant center he had stage II encephalopathy and his laboratory
studies showed a bilirubin greater than 40 mg/dL, aspartate aminotransferase
(AST) of 2800U/L, alanine aminotransferase (ALT) of 2300 U/L and
a protime international normalized ratio (INR) of 3.6. His viral serologies
revealed positive hepatitis B surface antigen, negative hepatitis B IgM
core antibody, positive hepatitis B e antibody, and negative hepatitis
C antibody. He had no history of exposure or ingestion of potential hepatotoxins,
and no risk factors for hepatitis B except for his Asian background. He
deteriorated over the next 12 h and required intubation. It became known
that the patient was a Jehovah's Witness and that he had expressed
a strong convinction not to receive any blood or blood products,
even in life threatening situations. This was supported by a previously
signed statement, as well as by family members. Though liver
transplantation was felt to be necessary, it was considered too hazardous
and supportive measures were instituted. Bacause of continued deterioration
our center was contacted and we accepted the patient as a liver transplant
candidate since this was the only option in this young man.
Upon arrival, the patient was in fulminant hepatic failure with stage
IV coma. He had good renal funcion, a hematocrit of 34%, protime of 46
s, bilirubin of 32.2 mg/dL, and no evidence of contraindications to liver
transplantation. The therapeutic options were discussed with patient's
family, who reaffirmed their religious convincion that no blood or blood
products, including albumin, be administered. They consented to a liver
transplant with the understanding that the patient may exsanguinate without
blood transfusions. They also consented to the use of veno-venous bypass
and a continuous circuit cell saver during the operation.
A suitable donor became available within 12h, and the patient underwent
orthotopic liver tranplantation on 21 Jaunary 1995 using standard techniques
including veno-venous bypass. Intraoperative monitors included radial and
pulmonary arterial pressure catheters, as well as standard electrocardiogram,
blood pressure and pulse oximetry. Anesthesia was maintained with isoflurane
0,2%, thiopental 1-3 mg/kg/h, and supplemented with fentanyl. Aprotinin
was administered throughout the case (test dose, bolus of 2x106
U, then infusion of 50,000 U/h). Estimated blood loss was 400 cm3
and the total fluid replacement was 4300 cm3 of PlasmalyteR.
The patient remained hemodynamically stable throughout the procedure, and
immediate graft function was noted. Immunosuppression was with steroids
and FK506. Hepatitis B immune globulin was administred according to the
UCLA protocol. Post-operative blood draws were kept to a minimum, and pediatric
phlebotomy tubes were used. The patient's mental status normalized, and
he was extubated on postoperative day (POD) 5, and transferred out of the
ICU on POD 7. He was started on erythropoietin, and oral iron supplementation
was initiated when the patient as able to resume a diet. His immediate
postoperative hematocrit was 29%; the nadir was 23,5% on POD 8, but increased
steadily since then. He was discharged from the hospital on POD 18 with
excellent hepatic funcion. He is doing well 6 months post-transplant, and
his most recent hematocrit is 44%.
DISCUSSION
...Liver transplantation without using blood presents a formidable
challenge. With the numerous advances in liver tranaplantation and increased
experience, there has been a trend towards liberalization of recipient
selection criteria. More difficult and challenging patients have been succcessfully
transplanted. The transplantation of a Jehovah's Witness patient is an
extreme example of this trend. Ramos et al.in 1994 reported 4 JW patients
who underwent liver transplantation. These patients were selected on strict
criteria that included a protime less 15 s, hematocrit greater than 35%
and the absence of renal failure or other organ dynsfunction. They were
prepared preoperatively by weeks of erythropoietin therapy, and the use
of albumin was accepted by the patients. Three patients that met the criteria
were successfully transplanted without transfusions. Our patient differed
in that he met non of the above criteria. He was in fulminant hepatica
failure with encefalopathy; his protime was 46 s, his
hematocrit was 34%, and the use of albumin was not acceptable.
given the advanced nature of our patient's hepatic failure, and continued
deterioration despite medical management, his prognosis was dismal without
transplantation. Owing to the emergent nature of the transplantation, preoperative
preparation with erythropoietin was not an option.. We felt, however,
that given the fact that liver replacement was the only optin for patient
survival in this previously healthy patient, the risks were acceptable
for an experienced team.
Intraoperative measures in this patient included meticulous
dissection, wich was done exclusively wit electrocautery,
and use of veno-venous bypass. Though
use of veno-venous bypass requires two extra incisions and additional operative
time, we chose to use it in this case for several reasons. It allows for
hemodynamic stability without excessive fluid administration and safe extension
of the anhepatic phase for precise vascular anastomoses and for achieving
adequate hemostasis, expecially in retrohepatic space. Studies have suggested
decreased blood requirements as well as better support of renal function
with veno-venous bypass. Use of the cell saver
in this patients required modification of the tubing circuit in order to
accomodate the wishes of the family that withdrawn blood be kept in continuity
with the patient at all times. It was, however, not a factor due to the
low volume of blood loss.
In addition to meticulous surgical techinque, antifibrinolytic agents
have been shown to be beneficial in liver transplantation. We chose to
use aprotinin for its potent antifibrinolytic
effects and demonstrated benefits in decreasing the need for transfusion
during liver transplantation. Aprtotinin's mechanism of action appears
to be a reduction in tissue plasminogen activator activity and a reducion
in alpha-2-antiplasmin degradation. The drug is usually well tolerated,
though anaphylactic reactions and thrombotic complications may result from
its use. The precise indications for aprotinin use in liver transplantation
have yet to be determined; however, it is a powerful antifibrinolytic drug
that can be an important adjunct to careful surgical technique.
The precise crystalloid solution chosen
to mantain normovolemia was carefully considered. Infusion of more than
15 cm3/kg/h of normal saline dilutes extracellular buffers and may cause
hyperchloremic acidosis. For this reason crystalloid replacement was accomplished
with Plasmalyte, a balanced salt solution.
We were limited in the colloid solutions that could be used, since albumin
was not permitted. Hetastarch is an option
that may be useful in maintaining osmotic pressure in patients with liver
disease and severe hypoalbuminemia. It was not used, however, due to its
potential for worsening coagulopaty and dissemiated intravascular coagulation.
Barbiturates were used as a maintenance
anesthetic because of their known effects in decreasing cerebral oxygen
consumption and possibly decreasing total body oxygen consumption. A majior
factor in decreasing oxygen consumption is the treatment of hyperthermia.
In this case, the patient was allowed to become mildly hypothermic, but
severe hypothermia was avoided due to its deleterious
effect on coagulation.
During the postoperative period, we maximized erythropoiesis with early
total parenteral nutrition, iron
supplementation and erythropoietin.
Erythropoietin has been shown to be effective in treating anemia in renal
failure patients and has also bee used succesfully in surgical JW patients.
Other measures that have been used in severely anemic JW patients are parenteral
iron and perfluorochemical blood substitute,
Fluosol, but these were not necessary in our patient.
This case demonstrates that emergent liver transplantation is
possible without the use of blood and blood products in the hands of ana
experienced team, and that these patients should not be a priori excluded
from this life-saving procedure. |