Over 30 million people worldwide have sickle cell disease (SCD), a multisystemic illness characterized by hemolytic anemia, increased susceptibility to infections, and vascular occlusion that leads to ischemic tissue injury [1,2]. Because of the nature of the complications of SCD, patients with this illness are more likely to undergo surgery compared to the general population [3]. SCD patients pose unique challenges in surgery due to vulnerabilities to the physiological stresses of surgery and anesthesia [1]. Perioperative management of sickle cell patients requires an understanding of the pathophysiology of SCD, as well as a collaborative effort between the entire surgical team to provide quality care [1].
The normal adult hemoglobin, Hemoglobin A (HbA), is the product of two globin chains: alpha and beta [1]. The sickle hemoglobin mutation (HbS) results from single amino acid substitution of valine for glutamic acid in the 6th position of the beta-globin chain [1]. The hallmark of SCD is recurrent vascular occlusion, in which HbS polymerization plays an essential role [1]. Hemoglobin deoxygenation in SCD leads to sickling of the red blood cells (RBCs) as a result of HbS polymerization [1]. Causes of hemoglobin deoxygenation include hypoxia, infection, inflammation, dehydration, hypotension, cold temperature, acidosis, and more [1]. Sickled RBCs adhere to the vascular endothelium and participate in vascular occlusion [1]. The occlusion delays flow, further enhancing deoxygenation of RBCs and worsened polymerization [1].
Surgery exposes patients to many of the factors that are known to lead to red blood cell sickling [3]. Even with meticulous perioperative care, 25% to 30% of SCD patients experience a postoperative complication [3]. Frequent surgical procedures in SCD patients include adenotonsillectomy, cholecystectomy, splenectomy, and hip arthroplasty [3]. Abdominal operations, particularly cholecystectomy and splenectomy, are the most common type of surgery in SCD patients [3].
Special steps should be taken during the perioperative process to avoid triggering a sickle cell crisis [1]. In the pre-operative phase, SCD patients should avoid fasting [1]. Since intracellular dehydration is a known trigger for HbS polymerization, patients are encouraged to drink clear fluids up until 2-4 hours before surgery [1]. For patients undergoing moderate or major procedures, warm intravenous hydration is often used to prevent both dehydration and hypothermia [1]. However, excessive fluid loading must be avoided in SCD patients with existing cardiac or pulmonary issues [1]. Hypoxia is another potential trigger for sickle cell crisis [1]. To identify those who may need supplemental oxygen, SCD patients require constant oxygen monitoring [1,3].
In many parts of the developed world, SCD patients often receive a blood transfusion before surgery [3]. However, the practice remains controversial [3]. The goal of blood transfusion is to reduce the percent HbS concentration and improve tissue oxygen delivery, but it also carries the risk of increasing blood viscosity [1]. Although centers that do not routinely offer preoperative transfusion to SCD patients have not seen an increased risk of postoperative complications, data has shown that there is a net benefit of increased tissue oxygen delivery over increased viscosity when the transfused hemoglobin level is kept at or below 10 g/dl [1].
During surgery, anesthetic techniques must minimize venous stasis and avoid the use of respiratory depressants [1]. Circulatory stasis can be avoided by providing adequate hydration, involving prompt replacement of intraoperative fluid loss to prevent hypovolemia [5]. It is also essential to keep the operating environment to as near normal temperature as possible to avoid hypothermia [5]. Furthermore, evidence has shown that minimally invasive surgery leads to improved postoperative outcomes compared to traditional surgery [5]. Minimally invasive surgery has proven to be safe in SCD patients and should be considered whenever possible [5].
Postoperatively, all SCD patients should receive oxygen supplementation, intravenous hydration, and pharmacologic thromboprophylaxis [5]. Early mobilization has shown to play a significant role in reducing postoperative complications [5]. To minimize pain, non-steroidal anti-inflammatory drugs and epidural analgesia can be used to avoid respiratory depression [5].
References
- Adjepong, K., Otegbeye, F., & Adjepong, Y. (2018). Perioperative Management of Sickle Cell Disease: A Narrative Review. Mediterranean Journal of Hematology and Infectious Diseases, 10(1), 2018032. doi:10.4084/mjhid.2018.032
- Schnog, J., Duits, A., Muskiet, F. et al. (2004). Sickle cell disease; a general overview. The Netherlands Journal of Medicine, 62(10), 364–374. PMID:15683091
- Buck, J., & Davies, S. (2005). Surgery in Sickle Cell Disease. Hematology/Oncology Clinics of North America, 19(5), 897-902. doi:10.1016/j.hoc.2005.07.004
- Khurmi, N., Gorlin, A., & Misra, L. (2017). Perioperative considerations for patients with sickle cell disease: a narrative review. Canadian Journal of Anesthesia, 64(8), 860-869. doi:10.1007/s12630-017-0883-3
- Meshikhes A. N. (2007). Towards safer surgery in patients with sickle cell disease. Saudi Medical Journal, 28(12), 1788–1790. PMID:18060203
