Platelets are components of our blood, generated by megakaryocytes in the bone marrow, and play a critical role in hemostasis. They respond to bleeding by facilitating formation of a blood clot (Greenberg & Kaled, 2013). Thrombocytopenia, also known as a platelet count less than 150,000/uL, stems from a variety of causes (Greenberg & Kaled, 2013). Low platelets in patients presenting for a procedure can be a cause for concern, as this condition can impact anesthesia and surgery.

Mild to moderate thrombocytopenia is defined by a platelet count between 75,000/u/L and 150,000/uL. Moderate to severe thrombocytopenia is 20,000/uL to 75,000/uL. Very severe thrombocytopenia is indicated by a platelet count below 20,000/uL (Skeith et al., 2020). Manifestations of thrombocytopenia vary, but most patients become symptomatic when the platelet count drops below 50,000/uL (Greenberg & Kaled, 2013). Causes of thrombocytopenia include decreased production of platelets, increased destruction of platelets, sequestration of platelets in the spleen, and dilution of blood (Smock & Perkins, 2014).

Evaluation of patients for a hematologic history is essential before a procedure. Additionally, a thorough review of medication history, including use of antiplatelet and anticoagulation agents or herbal medications is crucial (Nagrebetsky, 2019) (Graetz et al., 2023). Various tests can be used to assess platelet count before surgery. Some common tests include a complete blood count (CBC) and a peripheral blood smear if values in the CBC appear abnormal. Patients with a personal or family history suggestive of a hematologic disorder may require additional testing (Graetz et al., 2023).

For patients with known thrombocytopenia, collaboration among the surgeon, hematologist and anesthesiologist is necessary to determine an appropriate platelet count for the procedure viable and if necessary, plans to address thrombocytopenia. In general, surgery and anesthesia can proceed under careful monitoring with low platelets as long as platelet counts are greater than 50,000/uL. The necessary platelet count may be greater than 100,000/uL for neurosurgery or ocular surgery (Graetz et al., 2023). If a patient with severe thrombocytopenia requires emergency surgery, they will likely need and receive a platelet transfusion (Graetz et al., 2023).

Thrombocytopenia must also be considered in the postoperative setting. There are many different causes of low platelets after surgery and anesthesia (Skeith et al., 2020). While it may be difficult to identify the cause, a good place to start would be by examining the time course of postoperative thrombocytopenia. For example, thrombocytopenia which occurs within 4 days of the surgery may be due to hemodilution and increased perioperative platelet consumption while thrombocytopenia with a later onset may be due to consumptive or destructive causes such as disseminated intravascular coagulation or heparin-induced thrombocytopenia (Skeith et al., 2020).

The functional status of platelets also affects a thrombocytopenic patients’ likelihood of bleeding. In fact, platelet function may “better predict surgical bleeding than the platelet count” (Graetz et al., 2023). Uremic patients, patients with severe liver disease, and patients with inherited disorders of platelet function may manifest with symptoms of thrombocytopenia due to dysfunctional platelets (Graetz et al., 2023).

Ultimately, patients with low platelets introduce important considerations for surgery and anesthesia. A collaborative and personalized approach is essential to ensure successful outcomes in the perioperative period for patients with thrombocytopenia. Treatment decisions and feasibility of proceeding with surgery will depend on the cause and severity of thrombocytopenia and the planned surgical procedure.

References

Nagrebetsky, A et al. “Perioperative thrombocytopenia: evidence, evaluation, and emerging therapies.” British journal of anaesthesia vol. 122,1 (2019): 19-31. doi:10.1016/j.bja.2018.09.010

Greenberg, Edythe M, and Elizabeth S Kaled. “Thrombocytopenia.” Critical care nursing clinics of North America vol. 25,4 (2013): 427-34, v. doi:10.1016/j.ccell.2013.08.003

Smock, K J, and S L Perkins. “Thrombocytopenia: an update.” International journal of laboratory hematology vol. 36,3 (2014): 269-78. doi:10.1111/ijlh.12214

Skeith, Leslie et al. “A practical approach to evaluating postoperative thrombocytopenia.” Blood advances vol. 4,4 (2020): 776-783. doi:10.1182/bloodadvances.2019001414

Graetz, Thomas, et al. “Perioperative Blood Management: Strategies to Minimize Transfusions.” UpToDate, Wolters Kluwer, 23 Aug. 2023, www.uptodate.com/contents/perioperative-blood-management-strategies-to-minimize-transfusions.