sickle cell anemia

1. Sickle Cell Anemia
Case presentation for caesarian section
1397/6/13
Reference :
stoelting's anesthesia and co-existing
disease ( seventh edition )

2. Sickle S Hemoglobin
• Sickle cell disease is a disorder caused by the substitution of
valine for glutamic acid in the β-globin subunit.
• In the deoxygenated state, HbS undergoes conformational
changes that expose a hydrophobic region of the molecule. In
states of severe deoxygenation the hydrophobic regions
aggregate, and this results in distortion of the erythrocyte
membrane, oxidative damage to the membrane, impaired
deformability, and a shortened lifespan of only 10–20 days.

3. • Sickle cell anemia, the homozygous form of HbS disease,
presents early in life with severe hemolytic anemia and
progresses to significant end-organ damage involving the bone
marrow, spleen, kidneys, and central nervous system.
• Patients experience episodic painful crises (vasoocclusive
crises) characterized by bone and joint pain that may or may not
be associated with concurrent illness, stress, or dehydration.
• The severity and progression of the disease can vary
remarkably.
• Organ damage can start early in childhood, with recurrent
splenic infarction culminating in loss of splenic function in the
first decade of life.

4. • The kidney can demonstrate painless hematuria and loss of
concentrating ability as an early feature and then progress to
chronic renal failure in the third or fourth decade of life.
• Pulmonary and neurologic complications are the major
causes of morbidity and mortality.
• Lung damage results from chronic persistent inflammation.
• Neurologic complications include stroke, usually as a result of
arterial disease rather than sickling. Adolescents present
with cerebral infarction, whereas adults typically develop
hemorrhagic strokes.

5. • Acute chest syndrome, a pneumonia-like complication, is
characterized by the presence of a new pulmonary
infiltrate involving at least one entire lung segment plus at
least one of the following
 chest pain
 fever
 tachypnea
 Wheezing
 cough

6. Sickle C Hemoglobin
• The prevalence of HbC is about one-fourth that of HbS.
• HbC causes the erythrocyte to lose water via enhanced activity
of the potassium chloride cotransport system. This results in
cellular dehydration that in the homozygous state may produce
a mild to moderate hemolytic anemia.
• HbS trait or HbC trait in isolation cause no symptoms.However,
when they are present together (HbSC disease) they can
produce sickling and complications similar to those of HbSS
disease.
• It appears that the dehydration produced by HbC increases the
concentration of HbS within the erythrocyte, exacerbating its
insolubility and tendency to polymerize.

7. Sickle Hemoglobin–β-Thalassemia
• Among African Americans, the frequency of the β-thalassemia
gene is only onetenth that of the gene for HbS.
• The clinical presentation of this compound heterozygous state
is largely determined by whether it is associated with reduced
amounts of HbA (sickle cell–β+ thalassemia) or no HbA
whatsoever (sickle cell–β0 thalassemia).
• In the absence of any HbA, patients experience acute
vasoocclusive crises, acute chest syndrome, and other sickling
complications at rates approaching those of patients with HbSS.

8. Management
of
Anesthesia

9. Management of Anesthesia.
• Sickle cell trait does not cause an increase in perioperative
morbidity or mortality.
• However, sickle cell disease is associated with a high incidence
of perioperative complications.
• Risk factors include :
 Advanced age
 Frequent and severe recent episodes of sickling
 Evidence of end organ damage (e.g., low baseline oxygen
saturation, elevated creatinine level, cardiac dysfunction,
history of stroke)
 Concurrent infection

10. Risks intrinsic to the type of surgery are also important
considerations :
 Minor procedures considered to be low risk
 Intra abdominal operations categorized as intermediate risk
 Intracranial and intra thoracic procedures classified as high
risk
Among orthopedic procedures, hip surgery and hip
replacement in particular are associated with a high risk of
complications, including excessive blood loss and sickling events.

11. • Patients undergoing low-risk procedures now rarely require
any preoperative transfusion
• patients undergoing moderate- to high-risk operations need
only have preoperative anemia corrected to a target Hct (all Hb
types) of 30%.However, some suggest that HbS levels below
30% are desirable for major noncardiac surgery, and HbS
levels below 5% are desirable for cardiac surgery involving
cardiopulmonary bypass, which is associated with several
factors that can promote sickling and hemolysis.
• In such patients, exchange transfusion can be used
perioperatively in conjunction with hydroxyurea (which
increases levels of HbF) to achieve the desired low
concentration of HbS.

12. • Anesthetic technique does not appear to significantly affect
the risk of complications stemming from sickle cell disease.
• Secondary goals like avoiding dehydration, acidosis, and
hypothermia do help reduce the risk of perioperative sickling
events.
• Use of occlusive orthopedic tourniquets is not
contraindicated, but the incidence of perioperative
complications is increased with their use.

13. • Postoperative pain requires aggressive, typically
multimodal, pain management.
• Patients often have a degree of tolerance to opioids, and a
subset of patients may even have opiate addiction, but these
facts must not interfere with appropriate perioperative pain
management.
• Despite concerns that regional anesthesia might have
detrimental effects in sickle cell patients, it is not
contraindicated and may offer an advantage in pain control.

14. • Acute chest syndrome may develop 2–3 days
postoperatively
• Requires treatment of hypoxemia, pain, hypovolemia,
anemia, likely infection, and possible venous
thrombosis.
• Mild cases may respond to simple transfusion.
• Exchange transfusion may be needed in severely affected
patients.