Haematological Physiology, Haemostasis, Transfusion and Immunology — WACS Viva & Clinical Scenarios (Physiology and Applied Physiology)

Exam-style haematological physiology, haemostasis, transfusion and immunology viva scenarios with examiner probes and model answers for ANAESTHESIA candidates.

Scenarios covered

• SCENARIO 1: Describe the Cell-Based Model of Haemostasis. Detail the three overlapping phases: (a) Initiation, (b) Amplification, and (c) Propagation. Explain how this modern model differs from the classical intrinsic and extrinsic coagulation cascades.
• SCENARIO 2: A 24-year-old primigravida with known Sickle Cell Disease (HbSS) presents in labour and requires emergency Caesarean section. Detail the molecular and biophysical basis of haemoglobin S polymerization. Explain the physiological triggers that precipitate sickle crisis, and outline the anaesthetic physiological strategies to prevent sickling intraoperatively.
• SCENARIO 3: Compare and contrast the pathophysiology, clinical presentation, diagnostic criteria, and physiological management of Transfusion-Related Acute Lung Injury (TRALI) and Transfusion-Associated Circulatory Overload (TACO).
• SCENARIO 4: Detail the biochemical, cellular, and functional changes that occur in packed red blood cells during prolonged storage (the red blood cell storage lesion). Explain the physiological consequences of transfusing 10 units of banked blood stored for 35 days to an adult trauma patient.
• SCENARIO 5: Describe the Complement System. Detail the mechanisms of activation and the cascade steps of the Classical, Alternative, and Lectin pathways. Explain the formation of the Membrane Attack Complex (MAC, C5b-9) and the physiological roles of complement split products (C3a, C5a) in inflammation and anaphylaxis.