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2nd Year MBBS - ICMHE Practical Spotter Guide

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PHARMACOLOGY SPOTTERS

1. Stethoscope

• Identify: Binaural stethoscope (acoustic type)
• Parts: Earpieces (binaurals), tubing, chest piece (diaphragm + bell), stem
• Uses: Auscultation of heart sounds, lung sounds, Korotkoff sounds during BP measurement
• Key questions:
  • "What are the parts of a stethoscope?"
  • "What is the difference between the diaphragm and bell?"
  • "What sounds do you hear with the bell?" (low-pitched: heart murmurs, S3, S4)
  • "What is Laennec's contribution?" (inventor of stethoscope, 1816)

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2. Sphygmomanometer (BP Apparatus)

• Types: Mercury, aneroid, digital
• Parts: Cuff (bladder), manometer, bulb/pump, pressure control valve, tubing
• Normal BP: 120/80 mmHg
• Key questions:
  • "What are Korotkoff sounds? Name all 5 phases."
  • "What is systolic and diastolic pressure?"
  • "Where do you place the cuff and stethoscope?"
  • "What is the cuff size for an adult?" (12-13 cm wide, 35 cm long)
  • "What errors occur in BP measurement?"
  • "What is auscultatory gap?"
  • "What is pulse pressure and mean arterial pressure?"
  • "Which artery is compressed?" (Brachial artery)

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3. Clinical Thermometer

• Types: Mercury, digital, infrared (tympanic)
• Parts: Bulb, capillary tube, constriction, scale (Fahrenheit/Celsius)
• Normal temperature: 98.6°F / 37°C
• Key questions:
  • "What is the purpose of the constriction in a mercury thermometer?"
  • "Normal body temperature range?"
  • "Where can temperature be measured?" (oral, axillary, rectal, tympanic)
  • "Which site gives highest temperature?" (rectal > oral > axillary)
  • "Define fever/pyrexia, hyperpyrexia, hypothermia."
  • "Why is mercury used?" (uniform expansion, easy to read)

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4. Pulse Oximeter

• Principle: Uses two wavelengths of light (660 nm red + 940 nm infrared) - Beer-Lambert law
• Displays: SpO2 (oxygen saturation) + Pulse rate
• Normal SpO2: 95-100%
• Key questions:
  • "What is the principle of pulse oximetry?"
  • "What does SpO2 measure?" (peripheral oxygen saturation of hemoglobin)
  • "What is normal SpO2?"
  • "What causes false readings?" (nail polish, cold extremities, poor perfusion, carbon monoxide poisoning - falsely HIGH)
  • "What is the difference between SpO2 and SaO2?"
  • "Where is it placed?" (finger, toe, earlobe)
  • "What is hypoxia vs hypoxemia?"

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5. Kidney Tray / Galley Pot

• Use: Carrying instruments, waste collection
• Material: Stainless steel

6. Syringes & Needles

• Types: 1mL (insulin/tuberculin), 2mL, 5mL, 10mL, 20mL
• Parts: Barrel, plunger, nozzle (luer lock/slip), needle (hub, shaft, bevel)
• Key questions:
  • "What is the gauge of needle?" (higher gauge = thinner needle)
  • "Routes of drug administration?" (IV, IM, SC, ID)
  • "What gauge needle for IM injection?" (21-23G)
  • "What is the angle for IM, SC, ID injections?" (90°, 45°, 15°)

7. IV Cannula / Infusion Set

• Parts of IV set: Drip chamber, roller clamp, needle, tubing
• Key questions: Drops per minute calculation, types of IV fluids

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PHYSIOLOGY SPOTTERS (2nd Year)

8. Sahli's Hemoglobinometer

• Use: Measures hemoglobin concentration
• Method: Acid hematin method
• Key questions: Normal Hb values (Male: 13-17 g/dL, Female: 12-15 g/dL), procedure

9. Wintrobe Tube

• Use: ESR measurement (Wintrobe method) + PCV/hematocrit
• Key questions: Normal ESR (male <15, female <20 mm/hr), what increases ESR?

10. Westergren Tube / Pipette

• Use: ESR by Westergren method (gold standard)

11. Haemocytometer (Neubauer Chamber)

• Use: RBC and WBC count
• Key questions: Total RBC count (M: 4.5-5.5 million, F: 3.8-5.0 million), WBC count (4000-11000/μL)

12. Diluting Pipettes

• RBC pipette: Red bead, dilution 1:200
• WBC pipette: White bead, dilution 1:20

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PATHOLOGY SPOTTERS (2nd Year)

13. Vacutainer Tubes (color-coded)

• Key questions: "What is the order of draw?", "Why EDTA for CBC?", "What anticoagulant in blue tube?"

14. Urinometer

• Use: Measures specific gravity of urine
• Normal specific gravity: 1.003-1.030
• Principle: Buoyancy/flotation

15. Esbach's Albuminometer

• Use: Semi-quantitative measurement of protein in urine

16. Lancet / Pricking Needle

• Use: Capillary blood sampling (finger prick)

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QUICK-FIRE VIVA PREP

• Bell: low-frequency sounds (mitral stenosis murmur, S3, S4) - applied lightly
• Diaphragm: high-frequency sounds (normal heart sounds, breath sounds, bowel sounds) - applied firmly

1. Tapping sound (systolic BP)
2. Swishing/murmur
3. Crisp, loud tapping
4. Muffled sound
5. Silence (diastolic BP)

• Right subclavian artery is a direct branch of aorta; slightly higher pressure

• SpO2 = pulse oximetry (non-invasive estimate)
• SaO2 = arterial blood gas (direct measurement, gold standard)

• Carboxyhemoglobin absorbs light at the same wavelength as oxyhemoglobin - gives falsely high reading

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EXAM TIPS FOR TOMORROW

1. Pick up the instrument confidently - state its name immediately
2. Describe it - material, color, size, parts
3. State its use - what it measures and normal values
4. Mention principle where relevant (oximeter, urinometer)
5. Be ready for "what if" questions - errors, limitations, contraindications
6. Vacutainer tube colors are very commonly asked - memorize the table above

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ICMHE 2nd Year MBBS - Complete Spotter Guide

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1. STETHOSCOPE

Identification

• Acoustic binaural stethoscope
• Parts: Earpieces → Binaurals → Tubing → Chest piece (diaphragm + bell) → Stem

Expected Questions

• Earpieces (binaurals), spring, tubing (Y-shaped), chest piece (has diaphragm and bell), stem/head

• René Laennec, 1816, in Paris

• Uses ultrasound to detect blood flow; used in fetal heart monitoring

• Auscultation of: heart sounds, lung/breath sounds, bowel sounds, Korotkoff sounds (BP), carotid bruits

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2. BP CUFF (Sphygmomanometer)

Identification

• Mercury / aneroid / digital sphygmomanometer
• Parts: Cuff (inflatable bladder) → Rubber tubing → Bulb (pump) → Pressure valve → Manometer

Expected Questions

• 120/80 mmHg (adult)
• Hypertension: ≥140/90 mmHg
• Hypotension: <90/60 mmHg

• 2-3 cm above the antecubital fossa, over the brachial artery

• Bladder: 12-13 cm wide, 35 cm long (covers ~80% of arm circumference)

• False silence between Phase I and II sounds in some hypertensive patients; can cause underestimation of systolic BP

• Cuff too small → falsely high reading
• Cuff too large → falsely low reading
• Not at heart level → positional error
• Talking/anxiety → falsely high
• Ignoring auscultatory gap → underestimate systolic

• Systolic BP - Diastolic BP = normally ~40 mmHg

• MAP = Diastolic + 1/3(Pulse Pressure) = ~93 mmHg normally

• Right subclavian arises directly from aorta; slightly higher pressure than left

• Brachial artery

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3. THERMOMETER

Identification

• Clinical mercury thermometer / digital thermometer
• Parts: Bulb → Capillary tube → Constriction → Stem → Scale (°F and °C)

Expected Questions

• 98.6°F = 37°C (oral)
• Range: 97-99°F (36.1-37.2°C)

Rectal > Oral > Axillary (remember: ROA - rectal on top)

• Prevents mercury from falling back into bulb after removal from patient; allows accurate reading

• Fever/Pyrexia: Temperature >37.2°C (oral)
• Hyperpyrexia: Temperature >41°C
• Hypothermia: Temperature <35°C
• Hyperthermia: Elevated temperature without infection (heat stroke)

• Uniform thermal expansion, clearly visible, doesn't wet glass, wide measurable range

• Mercury toxicity - replaced by digital thermometers

• Formula: °C = (°F - 32) × 5/9 = (98.6 - 32) × 5/9 = 37°C

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4. PULSE OXIMETER

Identification

• Finger-clip pulse oximeter (probe-type)
• Displays: SpO2 (%) + Pulse rate (bpm)

Expected Questions

• Based on Beer-Lambert Law - uses two wavelengths of light:
  • 660 nm (red light) - absorbed by deoxyhaemoglobin
  • 940 nm (infrared light) - absorbed by oxyhaemoglobin
• The ratio of absorption determines SpO2

• 95-100% (normal)
• 91-94% = mild hypoxia
• <90% = significant hypoxia (supplemental O2 needed)
• <85% = severe hypoxia

• Falsely HIGH: Carbon monoxide poisoning (COHb reads same as OxyHb), methaemoglobinaemia
• Falsely LOW: Nail polish (especially dark colors), dark skin pigmentation
• Unreliable: Poor peripheral perfusion, cold extremities, shivering, excessive movement, arrhythmias

• COHb absorbs light at the same wavelength (660 nm) as oxyhaemoglobin, so the machine cannot distinguish them - gives falsely high SpO2

• Finger (most common), toe, earlobe, nose bridge, forehead

• Pulse rate and waveform (plethysmograph)

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5. KNEE JERK HAMMER (Patella Hammer / Reflex Hammer)

Identification

• Triangular/tomahawk-shaped rubber head, metal handle
• Also called: Taylor hammer, patella hammer, tendon hammer

Expected Questions

• Knee jerk reflex = Patellar reflex

• Receptor: Muscle spindle (in quadriceps)
• Afferent: Femoral nerve → L2, L3, L4 (dorsal root)
• Centre: Spinal cord segment L2-L4 (mainly L3-L4)
• Efferent: Femoral nerve → Quadriceps femoris
• Effector: Quadriceps contracts → leg extends

• Deep tendon reflex (DTR) / Monosynaptic stretch reflex

• Patellar tendon → stretches quadriceps → activates muscle spindles → reflex contraction

• Lower motor neuron (LMN) lesion, peripheral neuropathy (e.g., diabetes), hypothyroidism, tabes dorsalis

• Upper motor neuron (UMN) lesion (stroke, MS, spinal cord lesion above L2)

• Sitting with legs hanging free OR lying with knee slightly flexed (examiner supports under knee)
• Strike the patellar tendon just below the patella

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6. QUEEN SQUARE HAMMER

Identification

• Long handle (about 30 cm), circular/disc-shaped rubber head
• Originally made with a coin weighted in rubber
• Specifically designed for eliciting plantar reflex (Babinski)

Expected Questions

• Primarily: Plantar reflex (Babinski sign)
• Also: Deep tendon reflexes (all), especially ankle jerk

• Stroke the lateral aspect of the sole of the foot from heel to ball, then curve medially across the metatarsal heads
• Use the handle or a key (blunt instrument)

• Dorsiflexion of big toe + fanning of other toes = ABNORMAL in adults
• Indicates UMN (Upper Motor Neuron) lesion
• Normal in infants up to 2 years (pyramidal tract not yet myelinated)

• Plantar flexion of toes (toes curl downward) = normal in adults

• Afferent: Sural nerve + tibial nerve
• Centre: S1-S2 spinal cord
• Efferent: Tibial nerve → toe flexors

• Oppenheim sign: Stroke along the tibia
• Gordon sign: Squeeze the calf
• Chaddock sign: Stroke below the lateral malleolus
• All have same significance as Babinski (UMN lesion)

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GOLDEN RULES FOR TOMORROW

1. Pick up the instrument → Name it immediately → State its use
2. Always mention normal values (BP 120/80, Temp 37°C, SpO2 95-100%)
3. For reflex hammers, always mention the spinal cord level (L3-L4 for knee jerk, S1-S2 for plantar)
4. Know UMN vs LMN differences - examiners love this distinction
5. For pulse oximeter - the Beer-Lambert Law + CO poisoning question is almost guaranteed
6. For thermometer - always remember Rectal > Oral > Axillary
7. Speak confidently, even if unsure - state what you know first

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• Colour-coded header bar (unique colour per instrument)
• Green normal values banner (BP, SpO2, Temp, reflex grade)
• Parts listed
• Key facts table (2-col: term + explanation, alternating row shading)
• Yellow viva questions box with the most expected questions

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PULSE - Complete Easy Guide 🫀

(From your ICMHE slides - explained like a friend)

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WHAT IS A PULSE? (Super Simple)

One-line definition: The expansion and elongation of the artery wall caused by blood being pushed by the heart.

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WHERE CAN YOU FEEL THE PULSE?

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HOW TO FEEL THE RADIAL PULSE (Step by Step)

• 🔵 Ring finger (nearest to elbow) = checks the force of pulse
• 🟡 Middle finger = feels the pulse
• 🔴 Index finger (nearest to hand) = blocks back-flow from ulnar artery

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8 THINGS TO CHECK WHEN FEELING THE PULSE

1. RATE (Speed)

• Normal: 60-100 bpm
• Less than 60 = Bradycardia (slow heart - think: "brady" = slow)
• More than 100 = Tachycardia (fast heart - think: "tachy" = fast)

Tip: Count for 15 seconds, multiply by 4. OR count for a full minute for accuracy.

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2. RHYTHM (Regular or Irregular?)

• Regular = normal (like a ticking clock - tick...tick...tick)
• Regularly irregular = irregular but in a pattern (tick...tick...PAUSE...tick...tick...PAUSE) - seen in extra beats (extrasystoles)
• Irregularly irregular = completely chaotic, no pattern at all - classic for Atrial Fibrillation (AF)

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3. VOLUME (Strong or Weak?)

• Reflects pulse pressure = Systolic BP minus Diastolic BP
• Normal pulse pressure = 30-60 mmHg
• High volume = big, bounding pulse
• Low volume = weak, thready pulse

Check volume at carotid, brachial, or femoral artery (not radial - it's too small).

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4. ARTERIAL WALL CONDITION

• Normally you CANNOT feel the artery wall itself
• In old people with atherosclerosis (hardening of arteries), you CAN feel it like a hard wire under the skin

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5. COMPARE BOTH RADIAL PULSES (Radio-Radial Delay)

• Delay on one side = something is blocking that artery (e.g., aortic dissection, subclavian artery blockage)

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6. RADIO-FEMORAL DELAY

• Normally they arrive at the same time
• Delay in femoral = suggests Coarctation of the Aorta (a narrowing in the main artery)

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7. SPECIAL CHARACTERS (Types of Abnormal Pulse)

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8. OTHER PERIPHERAL PULSES

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PULSE DEFICIT - What is it?

• Measured by: One person listens to heart with stethoscope, another counts wrist pulse simultaneously for 1 minute
• Seen in: Atrial Fibrillation, multiple ectopic beats

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ECTOPIC BEATS - Easy Explanation

• From atrium = SVT (Supraventricular Tachycardia) - can be stopped by vagotonic procedures
• From AV node = 40-60 bpm
• From ventricle = ~36 bpm - vagotonic procedures have NO effect

1. Carotid sinus massage - gently press the carotid artery in the neck (never if there's a bruit!)
2. Valsalva manoeuvre - bear down like you're straining
3. Modified Valsalva - blow hard into a syringe, then lie flat

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HOW TO DO A FULL PULSE EXAMINATION (Step-by-Step Procedure)

1. Wash hands
2. Introduce yourself, take consent
3. Patient sits comfortably
4. Feel radial pulse - note rate, rhythm, volume (count 1 full minute)
5. Compare both radial pulses (radio-radial delay?)
6. Feel brachial pulse - both sides
7. Feel carotid pulse - both sides, but NEVER both at the same time (can drop BP dangerously!)
8. Lie patient down for lower limb pulses
9. Feel femoral pulse - compare with radial (radio-femoral delay?)
10. Bend knee 30° - feel popliteal pulse
11. Feel dorsalis pedis (top of foot)
12. Feel posterior tibial (inner ankle)
13. Thank the patient

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HOW TO DESCRIBE PULSE IN EXAM (Gold Standard Answer)

"Pulse is 72 bpm, regular in rhythm, normal in volume and character, with no radio-radial delay or radio-femoral delay, and all peripheral pulses are palpable."

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QUICK REVISION TABLE

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TOP EXAM QUESTIONS FROM THIS TOPIC

1. "What is a pulse?" - Wave of expansion in artery wall due to ventricular systole
2. "Most common site?" - Radial artery
3. "Which finger checks force?" - Ring finger (proximal)
4. "What is pulse deficit?" - Difference between heart rate and pulse rate; seen in AF
5. "What is water-hammer pulse?" - High volume collapsing pulse in aortic regurgitation
6. "What is pulsus paradoxus?" - Exaggerated fall in systolic BP (>10 mmHg) on inspiration
7. "Irregularly irregular pulse = ?" - Atrial Fibrillation
8. "Never palpate both carotids simultaneously - why?" - Can cause severe drop in BP (vagal reflex) and stroke
9. "Radio-femoral delay suggests?" - Coarctation of the aorta
10. "Vagotonic procedures?" - Carotid sinus massage, Valsalva, Modified Valsalva

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