Patologias

CARVALHO, CATRE, PEREIRA ET AL.

Anesthesia in Patients with Positive
Direct Coombs Test. Report of Three
Cases
Joana Patrícia dos Santos Carvalho, M.D., Dora Lopes
Castelo Branco Catre, M.D., Cláudia Margarida Brito
Pereira, M.D., Marina Costa, M.D.

INTRODUCTION
Autoimmune hemolytic anemia (AHA) is caused by the presence
of non-specific and identifiable antibodies that react withantigens
on the surface of red blood cells. Anemia develops when the percentage of red blood cells destroyed exceeds the regenerative
capacity of the bone marrow. In autoimmune hemolysis, autoantibodies coating the red blood cells do not damage them, but they
cause hemolysis by activating complement, inducing interactions
with the mononuclear phagocytic system.
Neoplastic disease can beassociated with autoimmune hemolytic anemia (AHA), with consequent blood incompatibility
that hinders blood transfusion in those patients1.
The nature of the clinical evolution of AHA and treatment modalities includes therapeutic transfusions2.
Coombs test or Direct Antiglobulin Test (DAT) represents an
elementary and simple in vivo test to demonstrate the presence
of IgG and/or complement coatingthe surface of erythrocytes.
The use of DAT is more appropriate in hemolytic anemia when
an autoimmune origin is suspected. Positive DAT has an elevated predictive value of autoimmune origin in a patient with hemolytic anemia. However, a positive DAT does not necessarily
mean that an individual has hemolytic anemia and, at times, it
is positive in individuals histologically normal3.
In patientswith AHA, which is defined by the short life of red
blood cells due to the autoimmune humoral response associated
with a positive DAT, alloantibodies and, probably, autoantibodies, hinder the determination of compatibility when blood transfusions are necessary. In those patients, blood transfusions can
be disastrous and cause severe deleterious effects3.
The objective of this study was toreport and discuss the conduct in three patients with positive direct Coombs Test (CT)
and the impossibility to determine their blood group for surgical interventions for neoplastic disease.

CASE REPORT
Table I summarizes the evolution and the approach of the
three cases.

CASE 1
A 78-year old male patient previously healthy, without any history of prior transfusions or anesthetic-surgicalprocedures.
80

The patient was scheduled for exploratory laparotomy for a
colon neoplasia. Clinically, the patient had anemia (hemoglobin 8.8 g.dL-1) with positive DAT (Ig3+), which made it impossible to determine his blood type. He was treated with iron,
erythropoietin, immunoglobulin, and corticoids, and after five
days we were able to determine his blood type, O Rh negative. He wasclassified as ASA III.
The surgery (colostomy) was performed under general balanced anesthesia lasting 60 minutes. One unit of packed-red
blood cells (PRBC) was transfused due to blood loss with
hemodynamic instability. Post-transfusional exams showed
hemoglobin of 9.0 g.dL-1. The patient remained hemodynamically stable during the 120 minutes he stayed in the PostAnesthetic Care Unit (PACU).
In theward, four hours after discharge from the PACU, the patient became comatose (Glasgow 4) associated with worsening of the anemia (hemoglobin 7.0 g.dL-1, hematocrit 20%).
The patient died 24 hours after the surgery with a diagnosis of
an ischemic stroke.

CASE 2
A 77-year old male patient without history of blood transfusions or anesthetic-surgical procedures, scheduled for gastrectomy for anadenocarcinoma of the stomach.
The patient had atrial fibrillation (AF) and hypertension (HTN),
clinically controlled. He was classified as ASA III.
Laboratorial tests showed hemoglobin (Hb) at 14.0 g.dL-1 and
thrombocytopenia with 55x109 platelets.L-1. Since he had a
positive DAT (Ig4+), he was treated with corticoids and immunoglobulin for 25 days, but we were unable to determine his...