Download Sickle Cell Anemia in an Infant with Tricuspid Atresia

PBLD Table #2
Sickle Cell Anemia in an Infant with Tricuspid Atresia
Problem Based Learning Discussion
James J. Fehr, MD, Departments of Anesthesiology & Pediatrics
Kelly Chilson, MD, Department of Anesthesiology
Washington University in St. Louis
St. Louis Children’s Hospital
The perioperative management of patients with cyanotic heart disease is challenging and requires
close cooperation between anesthesiologists, cardiac surgeons, cardiologists and pediatric intensivists.
The perioperative management of sickle cell anemia presents considerable challenges as anesthetics for
even minor procedures hold the potential for significant complications. The combination of sickle cell
disease with cyanotic heart disease is encountered infrequently but when present can prove deadly.
Goals:
1. Understand the pathophysiology and palliation of tricuspid atresia
2. Discuss the anesthetic management of a patient with tricuspid atresia
3. Review newborn screening for sickle cell anemia
4. Review the anesthetic approach to patients with sickle cell disease
5. Discuss the management of cyanotic heart disease in a patient with sickle cell disease
Case:
Our patient had a prenatal diagnosis of tricuspid atresia. He was born at term to a 19 year old
P1G1 mother by cesarean section due to failure to progress. His birth weight was 2.97 kilograms and his
Apgars were 5 and 8. An umbilical venous line was placed and prostaglandin initiated. An
echocardiogram confirmed the diagnosis of tricuspid atresia with pulmonary atresia, a large atrial septal
defect, a single coronary artery and ductal dependant flow. He underwent a Blalock-Taussig shunt on his
sixth day of life, was extubated on the first postoperative day and had an uncomplicated postoperative
period. His newborn screen, sent while he was recovering from surgery, returned from the state lab two
weeks later positive for Hemoglobin SS [HbSS]. He subsequently required multiple anesthetics for
cardiac catheterizations and a Glenn shunt. This PBLD will review tricuspid atresia, the screening,
presentation and treatment of sickle cell disease, and how hemoglobinopathy complicates the
perioperative management of cyanotic heart disease. We will consider the challenges and pitfalls
inherent in anesthetizing a patient with tricuspid atresia and sickle cell disease.
Questions:
1. What is tricuspid atresia? How and when is it typically diagnosed?
2. What is the management of tricuspid atresia? What are the anesthetic concerns?
3. What is sickle cell disease? How and when is sickle cell anemia diagnosed?
4. What are principles guiding anesthetic management for patients with sickle cell disease?
5. How does sickle cell anemia complicate the anesthetic management of tricuspid atresia?
6. What is the long term impact of sickle cell anemia on the management of tricuspid atresia?
Tricuspid Atresia [TA] is a single ventricle lesion where there is complete obstruction of the
atrioventricular valve of the right ventricle. The prevalence ranges from 0.3-3.7% of congenital heart
defects and it occurs in approximately 1 in 15,000 live births. The majority of cases of TA [70%] have
normally related great arteries and about one third have D-transposition of the great arteries. Patients
with TA often have obstruction of pulmonary blood flow and typically present with central cyanosis
shortly after birth; echocardiography confirms the diagnosis. In order to survive, patients with TA
require an interatrial communication, such as a patent foramen ovale or an atrial septal defect, to provide
a pathway for systemic venous return. The treatment is surgical and patients are managed through a
series of staged procedures beginning with a Blalock-Taussig [BT] shunt, proceeding through Glenn
shunt, and concluding with the Fontan procedure. The BT shunt is a systemic to pulmonary connection,
most commonly from the left subclavian to the left pulmonary artery. The Glenn procedure, performed
at around 6 months of age, connects the superior vena cava directly to the pulmonary artery; the BT
shunt is taken down at that time. The final stage, the Fontan, performed by 2 or 3 years of age, connects
the inferior vena cava directly to the pulmonary artery and completes the repair. The Glenn and Fontan
procedures are preceded by a cardiac catheterization to assess pulmonary artery pressures and both
procedures are performed under cardiopulmonary bypass.
Tricuspid atresia is a challenging cyanotic heart lesion as a fine balance must be maintained
between the pulmonary and systemic circulations. Hyperventilation or high FiO2 delivery can result in
pulmonary vasodilatation and can lead to excessive pulmonary blood flow, high oxygen saturations and
hypotension. Hypoventilation or hypoxia can result in increased pulmonary vascular resistance and
decreased pulmonary blood flow, which can present as profound hypoxia with a satisfactory blood
pressure. Balancing the pulmonary and systemic blood flow is the principal challenge in managing a
child with a single ventricle. These children typically have umbilical arterial and venous access which
can be used for induction.
Our patient had been prenatally diagnosed with tricuspid atresia and was started on prostaglandin
following delivery and transferred to our cardiac intensive care. He underwent a successful BlalockTaussig shunt on day of life 6 and was extubated on the first postoperative day. The newborn screen was
sent in the postoperative period and returned two weeks later indicating that he had hemoglobin SS
disease. He was referred to the hematology sickle cell clinic and started on penicillin.
Sickle cell disease is an autosomal recessively inherited
disease in which a single amino acid substitution leads to
abnormal Hemoglobin S which aggregates in the presence of
hypoxia. These friable crescent shaped erythrocytes readily
hemolyze and their abnormal shape results in increased blood
viscosity, sludging and numerous severe and potentially life
threatening sequelae including acute chest syndrome, pain crises,
hemolytic crises and cerebrovascular accidents. Patients with
sickle cell are usually identified on the newborn screen, but the
timing of the newborn screen and the mechanism for follow up of
the results is variable amongst the states. Thus newborn babies
may present for anesthesia with unidentified sickle cell disease.
The presence of a high level of HbF is protective for newborns
and provides some degree of protection against sickle crises.
Patients with sickle cell disease may be diagnosed early in
life presenting with dactylitis, pain crises, hemolysis or stroke.
Sickle cell disease patients must remain well hydrated, and
precipitants of sickling such as hypoxia, hypotension, cold
temperature and inadequate pain relief, must be avoided. The perioperative management of these
patients is a significant challenge for the anesthesiologist as significant complications can occur even
with tight control of the patient’s physiology and the ambient environment. The inflammatory response
has also been implicated as a precipitating event for sickle cell crises and is a particular concern with
cardiac surgery as patients are exposed to the cardiopulmonary bypass circuit and frequently to extreme
temperatures.
The perioperative care of children with sickle cell typically includes reduction of their sickle
percent and optimization of their hematocrit through a simple transfusion or an exchange transfusion.
Recent practice has moved toward limiting transfusion for minor surgeries like myringotomies or
procedures such as MRI. Cases involving cardiopulmonary bypass, however, are never minor and would
always require exchange transfusion. An exchange transfusion is performed by removing the patient’s
blood and replacing it with an equal volume of packed red blood cells. This effectively dilutes the
percent of sickle cells in the patient’s bloodstream.
Children with sickle cell disease are at risk for multiple medical and functional complications.
They have an increased incidence of reactive airway disease and more frequent school absences than the
general population. They have medical complications which require surgical intervention including
cholelithiasis leading to cholecystectomy and sequestration requiring splenectomy. Of greatest concern,
children with sickle cell disease have an increased risk of stroke as well as silent ischemic events and
decreased cerebral blood velocity on transcranial Doppler studies. One third of these children will suffer
a stroke or silent ischemic event by the time they reach school age.
Our patient was seen at 3 months of age by hematology and cardiology who felt he was doing
satisfactorily. He was noted to be feeding well and gaining weight, his oxygen saturations were 85% and
he was taking aspirin and penicillin. His labs demonstrated a hemoglobin level of 16.3, and his Hb
electrophoresis demonstrated 50% HbF and 50% HbS. Due to the increased risk of stroke with his
elevated HbF, he was admitted to the hospital for exchange transfusion and cardiac catheterization in
anticipation of his Glenn shunt. The goal was to reduce his sickle percent to less than 10%; despite
multiple transfusions and multiple central lines, his lowest sickle percent was 27%. He went to OR for
Glenn shunt at 4 months of age, which was complicated by bleeding, but no significant hypotension; he
did well postoperatively and was extubated on postop day one. The child was transferred to the floor and
on the fifth postoperative day was noted to have two 30 second focal seizures. A stat head CT revealed a
large left sided middle cerebral artery infarction.
The administration of anesthetics for children with sickle cell disease must be guided by clear
communication between the anesthesiologist, the hematologist and the surgeon. Children who are
having a major procedure require optimization of their hemoglobin level with a simple or exchange
transfusion. This is for procedures with potential for significant blood loss, fluid shifts, or the need for
cardiopulmonary bypass. The goal would be to have a hematocrit around 30%; excessive transfusion
increases blood viscosity and increases the potential for stroke. The children should be encouraged to
take clear liquids up to 2 hours prior to surgery in order to remain well hydrated. They should be
instructed in the use of an incentive spironometer and should not undergo an elective procedure if they
have had an upper respiratory infection in the previous 4 weeks. It is preferable that these children do
not receive anesthesia at odd hours for elective cases due to their risk of perioperative complications.
Children with sickle cell can receive an oral premedication and induction can be by mask or
intravenously. However, obtaining intravenous access is often difficult in these children. The room
should be warm and an active warming system should be used to maintain normothermia. Fluids should
be administered to address maintenance needs as well as to replace ongoing and third spacing losses. If
blood loss is anticipated to be sufficient to require replacement, the blood should be set up ahead of time
as antibodies can result in significant difficulties in crossmatching blood products. Like hypotension and
hypothermia, hypoxia is to be avoided as all of these can initiate and exacerbated the cascade of
sickling. Pain should be well controlled. Regional techniques offer the potential to provide ongoing
satisfactory pain relief into the postoperative period. Patients with sickle cell disease often are on
chronic opiates and have increased opiate needs due to tolerance. There should be rapid correction of
poorly controlled pain and a PCA is reasonable approach to providing ongoing pain relief. The
administration of narcotics must be balanced with the predictable potential for respiratory depression as
well as the anticipated atelectasis that frequently occurs postoperatively. Patients must utilize incentive
spironometry, ambulate as early as possible, perform deep breathing and receive supplemental oxygen
as needed.
References:
1) Buchanan, GR, DeBaun, MR, et al. Sickle Cell Disease. Hematology, 2004; 35-47.
2) Firth, PG, Head, A. Sickle Cell Disease and Anesthesia. Anesthesiology, Sept 2004;101:766-785.
3) Josephson, CD, Su, L, et al. Transfusion in the Patient with Sickle Cell Disease: A Critical
Review of the Literature and Transfusion Guidelines. Transfusion Med Reviews, 2007; 118-133.
4) Law, MA, Dreyer, Z, et al. Staged Single Ventricle Palliation in an infant with Hemoglobin SC
Disease. Tex Heart Inst J, 2007; 34(4):439-441.
5) Lok, JM, Spevak, PJ et al. Tricuspid Atresia in Critical Heart Disease in Infants and Children.
2006; 799-822.
6) Marchant, WA, Walker, I. Anesthetic Management of the Child with Sickle Cell Disease. Ped
Anes, 2003; 13(6):473-489.
7) Sittiwangkul, R, Azakie, A, et al. Outcomes of Tricuspid Atresia in the Fontan Era, 2004. Ann
Thorac Surg, 2004; 77:889-894.