Makindo Medical Notes

Related Subjects: |OSCE Eye Exam |OSCE Ear Exam |OSCE Abdominal Exam |OSCE Ascites Exam |OSCE Jaundice Exam |OSCE Testicular Exam |OSCE Inguinal Exam |OSCE Upper limb Neurology |OSCE Lower limb Neurology |OSCE Face Neurology |OSCE Breast exam |OSCE Hypertension exam

🩺 How to Measure Blood Pressure Properly

• 🧘 Preparing the Patient: Seat the patient quietly for 5 minutes, feet flat on floor, arm supported at heart level.
• 🩹 Proper Cuff Placement: Correct size cuff is essential. Too small → falsely high, too large → falsely low. Bladder should encircle ≥80% of the arm, centred over the brachial artery.
• ✋ Estimate Systolic Pressure: Palpate brachial/radial artery, inflate cuff until pulse disappears → estimate systolic pressure.
• 🎧 Measuring BP: Place stethoscope over brachial artery. Inflate cuff to 20–30 mmHg above estimated systolic. Deflate slowly (≈2 mmHg/sec).
• 📈 Identify Pressures:
  • Systolic (Korotkoff I): First tapping sounds.
  • Diastolic (Korotkoff V): Disappearance of sounds. If sounds persist to zero (e.g. pregnancy), use muffling (Korotkoff IV).
• 📝 Recording: Note systolic/diastolic, arm used, cuff size, patient position. Take 2 readings ≥30 seconds apart and average.

📊 Blood Pressure in Humans

• Arterial Pulse Waveform: Produced by ejection of blood from LV. Dicrotic notch 🕳️ represents aortic valve closure.
• Korotkoff Sounds:
  • Phase I: First tapping (systolic).
  • Phase V: Disappearance (diastolic).

🧪 Clinical Findings

• Hypertension: >140/90 mmHg (clinic). ⬆️ risk CVA, MI, CKD.
• Pulse Pressure: (Sys – Dia). Narrow → AS. Wide → AR, PDA, thyrotoxicosis.
• Aortic Stenosis: Low pulse pressure, slow-rising carotid.
• Aortic Regurgitation: Wide pulse pressure, bounding pulse (Corrigan’s).
• BP Difference Between Arms:
  • 👉 Right > Left (>20 mmHg): left subclavian stenosis/dissection.
  • 👉 Left > Right: right subclavian stenosis.
  • 👉 Arm vs Ankle difference: consider PVD or coarctation.
• Normal Variation: Small 5–10 mmHg asymmetry between arms is common.

💡 The biggest pressure drop occurs across the arterioles, where resistance control is greatest (the main regulators of systemic vascular resistance).

⚖️ Control of Blood Pressure

• Neural Control:
  • Baroreceptors: Carotid sinus & aortic arch → detect stretch → adjust HR & SVR.
  • Sympathetic NS: ⬆️ HR, contractility, vasoconstriction.
  • Parasympathetic NS: Vagal tone → ⬇️ HR, vasodilation.
• Hormonal Control:
  • RAAS: Renin → Ang I → Ang II → vasoconstriction + aldosterone (Na⁺/H₂O retention).
  • ADH (vasopressin): ⬆️ water reabsorption, vasoconstriction.
  • ANP: Released when atria stretched → natriuresis & vasodilation.
• Renal Control: Kidneys regulate long-term BP via sodium & water balance.

📝 Exam Tips

• Always measure both arms initially.
• Ensure correct cuff size (common OSCE pitfall 🚩).
• In AF: take multiple readings and average due to beat-to-beat variation.
• Don’t talk during measurement – it elevates BP (“white coat effect”).