Point-of-Care Testing, Viscoelastometry, and Perioperative Ultrasound Instrumentation — WACS Viva & Clinical Scenarios (Clinical Measurement and Equipment)

Exam-style point-of-care testing, viscoelastometry, and perioperative ultrasound instrumentation viva scenarios with examiner probes and model answers for…

Scenarios covered

• SCENARIO 1: A 32-year-old polytrauma patient is admitted to theatre in haemorrhagic shock following a motor vehicle collision. A bedside Thromboelastograph (TEG) is performed 15 minutes into massive transfusion. The tracing reveals: Reaction time (R) = 14 min (normal 5-10), K time = 6 min (normal 1-3), Alpha angle = 38 degrees (normal 53-72), Maximum Amplitude (MA) = 32 mm (normal 50-70), and LY30 = 18% (normal < 3%). Detail the physical and mechanical operation of a TEG device, analyze each deranged parameter, and outline your precise blood component resuscitation plan.
• SCENARIO 2: You are performing a focused cardiac ultrasound (FATE) examination on a 64-year-old female who developed severe refractory hypotension following induction of general anaesthesia for an emergency hip fracture repair. Explain the physical principles of ultrasound generation via the piezoelectric effect, the choice of a phased-array probe over a linear probe, the Doppler shift equation, and how you sonographically assess left ventricular preload and contractility.
• SCENARIO 3: A 42-year-old male with acute pancreatitis and acute respiratory distress syndrome is ventilated in the ICU. You perform a bedside lung ultrasound using a curvilinear transducer. You observe bilateral diffuse B-lines (> 3 per rib space, 'lung rockets') in the anterior and lateral zones, with intact lung sliding and absence of pleural consolidation. Detail the physical acoustics responsible for B-line artifacts versus A-lines, and discuss how lung ultrasound differentiates cardiogenic/non-cardiogenic alveolar interstitial syndrome from chronic lung disease.
• SCENARIO 4: A 26-year-old unbooked parturient presents at 38 weeks gestation with active labor and a history of having eaten a heavy meal 2 hours prior. She requires an emergency caesarean section for fetal distress. You perform a bedside gastric ultrasound using a low-frequency curved-array probe in the right lateral decubitus position. Explain the physical scanning technique for the gastric antrum, how to measure the antral cross-sectional area (CSA), calculate estimated gastric volume, and formulate your airway management strategy.
• SCENARIO 5: During liver transplantation, a ROTEM analysis shows a normal INTEM and EXTEM profile, but the HEPTEM CT is 180 seconds while the INTEM CT is 380 seconds. Meanwhile, point-of-care blood gas reveals a blood glucose of 2.1 mmol/L and ionized calcium of 0.72 mmol/L. Explain the physical mechanics of ROTEM optical detection, interpret the differential HEPTEM/INTEM findings, explain the electrochemical measurement of ionized calcium and glucose, and outline your therapeutic interventions.