Letters to the Editor: Letters & Announcements
To the Editor:
We were interested to read a case report of successful tourniquet use in a sickle cell patient (Hb SS) undergoing knee replacement (1). A case series of 12 Hb SS patients from the same institution in Saudi Arabia also demonstrated use of tourniquets without complication (2). In interpreting these results, it is important to note that Saudi Arabian patients have the Arab-Indian Hb SS haplotype, characterized by more benign disease, attributed to a higher percentage of fetal hemoglobin in their circulation (an average of 25% versus 5–10% in African haplotypes) (3). A case series from Africa, in contrast to the Saudi Arabian experience, reported that 3 of 14 Hb SS patients developed sickle cell related complications after surgery with tourniquet use (4). Given that 83–100% of Hb SS patients in the United States are African haplotypes (6), tourniquet use may not be appropriate for most sickle cell patients in North America.
Also in this report (1), the patient underwent preoperative exchange transfusion reducing Hb S from 82.6% to 47%. However, a RCT demonstrated that simple preoperative transfusion (total Hb to 10 g/dL) was as effective as exchange transfusion (Hb S <30% of total) in preventing perioperative complications in Hb SS patients, and was also associated with a 50% reduction in transfusion-related complications (5). Thus, preoperative exchange transfusion is rarely indicated.
Jennifer M. Sarjeant, MD
Jeannie L. Callum, MD, FRCPC
Department of Anesthesia, University of Toronto, Toronto, Canada
Director of Transfusion Medicine, Sunnybrook and Women’s College Health Science Centre, Toronto, Canada
1. Al-Ghamdi AA. Bilateral total knee replacement with tourniquets in a homozygous sickle cell patient. Anesth Analg 2004;98:543–4.
2. Gyamfi YA, Sankarankutty M, Marwa S. Use of a tourniquet in patients with sickle cell disease. Can J Anaesth 1993;40:24–7.
3. Wood WG, Pembrey ME, Serjeant GR, et al. Hb F synthesis in sickle cell anemia: a comparison of Saudi Arab cases with those of African origin. Br J Haematol 1980;45: 431–45.
4. Oginni LM, Rufai MB. How safe is tourniquet use in sickle-cell disease? Afr J Med Med Sci 1996;25:3–6.
5. Vichinsky EP, Haberkern CM, Neumayr L, et al. A comparison of conservative and aggressive transfusion regimens in the perioperative management of sickle cell disease. N Engl J Med 1995;333:206–13.
6. Sarnaik SA, Ballas SK. Molecular characteristics of pediatric patients with sickle cell anemia and stroke. Am J Hematol 2001;67:179–82.