Anaesthesia Coffee Break Deep dive into blood pressure with Dr Stuart Watson - Prize winner and creator of Ketamine Nightmares
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Mar 20, 2022 In this engaging discussion, Dr. Stuart Watson, a specialist anaesthetist and the creator of Ketamine Nightmares, delves into the intricate world of blood pressure. He explores the key determinants of mean arterial pressure and how they relate to cardiac output and vascular resistance. Stuart also highlights the importance of tissue perfusion and oxygen delivery. Through captivating real-world cases, he shares insights on managing complex scenarios like post-CABG sepsis and carotid endarterectomy. Prepare for an informative journey through the physiology of blood pressure!
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Blood Pressure = Volume Over Compliance
- Blood pressure fundamentally equals arterial blood volume divided by arterial compliance.
- Cardiac output and SVR determine how much blood sits in the arteries by governing inflow and outflow.
Ohm's Law Needs Venous Pressure
- The common MAP = CO × SVR omits the downstream pressure term (CVP/RAP) required by Ohm's law.
- Tissue blood flow is better framed as (MAP − CVP)/SVR for perfusion calculations.
Pulse Pressure Reflects Stroke Volume/Compliance
- Pulse pressure ≈ stroke volume divided by arterial compliance, because rapid ejection changes arterial volume.
- Systolic and diastolic pressures are mean ± pulse oscillation rather than independent variables.