Neurophysiology, Cerebral Blood Flow and Intracranial Pressure Regulation — WACS Viva & Clinical Scenarios (Physiology and Applied Physiology)

Exam-style neurophysiology, cerebral blood flow and intracranial pressure regulation viva scenarios with examiner probes and model answers for ANAESTHESIA…

Scenarios covered

• SCENARIO 1: State the Monro-Kellie hypothesis. Draw and describe the intracranial volume-pressure curve, explaining the concepts of spatial compensation, intracranial compliance, and elastance. Detail the physiological compensatory mechanisms that operate when an intracranial mass expands.
• SCENARIO 2: A 32-year-old male with a severe traumatic brain injury has an intracranial pressure of 28 mmHg and an arterial blood pressure of 105/65 mmHg. Calculate his cerebral perfusion pressure (CPP). Describe the physiological factors regulating Cerebral Blood Flow (CBF), including blood pressure autoregulation, arterial blood gases (PaCO₂ and PaO₂), and cerebral metabolic rate (CMRO₂).
• SCENARIO 3: Describe the anatomy, formation, circulation, and absorption of Cerebrospinal Fluid (CSF). Compare the composition of normal CSF with that of blood plasma, detailing differences in protein, glucose, sodium, potassium, chloride, and pH levels.
• SCENARIO 4: Draw the cerebral autoregulation curve plotting Cerebral Blood Flow (CBF) against Mean Arterial Pressure (MAP). Illustrate how this curve is modified by: (a) chronic systemic hypertension, (b) severe hypercapnia, and (c) volatile anaesthetic agents at 1.5 MAC.
• SCENARIO 5: Outline the neuroanatomy and physiology of the ascending nociceptive pathways and the endogenous descending pain modulatory system. Explain the physiological mechanisms involved in peripheral sensitization and central sensitization (wind-up phenomenon) in the dorsal horn.