Case presentation An 82-year-old white woman was admitted for an elective right total knee replacement. She was a Jehovah's Witness with sickle cell trait. Her preoperative haemoglobin (Hb) was 10.4 g/dl and electrophoresis revealed sickle Hb (HbS) of 35%. She also had borderline low ferritin levels and was on parenteral iron therapy. She also had hypertension, hypertension-induced renal dysfunction and chronic pulmonary disease. She refused any form of blood transfusion, including re-infusion of shed blood. After discussion with surgical team it was decided to use tourniquet intraoperatively. Prior to induction 125 μg of fentanyl was given to obtund the hypertensive response to intubation. Rapid sequence induction of anaesthesia was conducted with propofol and suxamethonium as patient was obese and had a history of gastroesophageal reflux disease. The airway was secured uneventfully. Anaesthesia was maintained with air, oxygen and sevoflurane. Her end tidal was maintained between 3.9 and 4.2 kPa. Femoral and obturator nerve blocks were performed (with 30 and 5 ml of 0.25% bupivacaine, respectively) using a nerve stimulator. Forty milligrams of atracurium was then given. She had a 300-mmHg tourniquet pressure for nearly 90 min. Her blood pressure was elevated during surgery requiring intravenous labetalol. Postoperatively she did not manifest any painful crisis and her Hb was 8.4 g/dl. She was discharged after 8 days in hospital. Discussion Sickle cell disease is a common blood disorder that has affected millions worldwide. It is caused by inappropriate substitution of valine for glutamine at the sixth position of the β-globin chain. This altered Hb has a low affinity for oxygen and polymerizes to form insoluble crystals which disrupts the structure of the erythrocytes. In the homozygous state (sickle cell anaemia, HbSS) both genes are abnormal whereas in the heterozygous state (sickle cell trait, HbAS) only one chromosome carries the gene.1 Whereas sickle cell disease is associated with significant morbidity in terms of growth and development, renal disease, cerebral infarcts, splenic infarcts and haemolytic anaemia, sickle cell trait is usually asymptomatic and affected individuals have normal life expectancy. When deoxygenated Hb (HbSS) polymerizes, it damages the red cell membrane. Although this is reversible, with repeated sickling this could lead to irreversible damage to red cell membrane. Anaesthetic techniques for patients with sickle cell disease and trait have tended to focus mainly on preventing sickling by avoiding hypoxaemia, acidosis and maintaining body temperature and intravascular volume. The use of tourniquets in sickle cell disease and trait remains controversial, as they cause hypoxaemia, hypercapnoea and lactic acidosis in the isolated limb.2 Therefore, some authorities regard both conditions as definite contraindications for tourniquet application,3 although there are case reports revealing its successful use in patients with sickle cell disease4 and a study carried out revealing no increased evidence of complications when torniquets applied in patients with sickle cell trait.5 There is a case report that has suggested the initiation of sickle cell crisis in patients with sickle cell trait after application of tourniquets,6 and as such their use should be balanced against the risks in sickle cell trait.7 Haematologists regard sickle cell trait as a benign disease with low morbidity. The incidence of sickle cell trait in African–Americans is one in 12. The occurrence under anaesthesia of cerebral thrombosis, and other mishaps including sudden death in these individuals may suggest cause-and-effect but in reality there is no proven association.8 Therefore, from the haematological viewpoint the use of tourniquets in limb surgery is regarded as safe. In our case we believe that nonapplication of tourniquet in her case could be fatal not only because of her refusal of transfusion but also because of increased bleeding risk secondary to hypertension. Furthermore as she was a carrier her risk of going into a crisis was very low. Conclusion Providing anaesthesia to sickle cell disease/trait was considered a challenge and there was currently no consensus in anaesthetics over the use of tourniquets. We believe that although the situation is less clear in sickle cell disease, sickle cell trait should not be considered a contraindication to tourniquet application.
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Feb 1, 2011
Antonio Tsuneshige + 3
Open Access
