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CHOT QTP (Short Questions)

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Q1. Cardio-Respiratory & Metabolic Adjustments During Exercise (Isometric & Isotonic)

Cardiovascular Adjustments

• Heart rate rises at onset (due to psychic stimuli on medulla, mainly via decreased vagal tone)
• Systolic AND diastolic blood pressure rise sharply within seconds
• Stroke volume changes relatively little
• Blood flow to contracting muscles is reduced (vessel compression by tonically contracted muscles)
• Total peripheral resistance INCREASES (contracting muscles add to TPR)
• Cardiac output increases modestly

• Prompt increase in heart rate
• Marked increase in stroke volume (key difference from isometric)
• Net FALL in total peripheral resistance (vasodilation in exercising muscles)
• Systolic BP rises only moderately; diastolic usually unchanged or falls
• Cardiac output may exceed 35 L/min (proportional to O2 consumption)
• Trained athletes: larger stroke volume, lower heart rate, larger hearts

Respiratory Adjustments

• Increased minute ventilation (rate and depth)
• Greater O2 extraction from blood (widened a-v O2 difference)
• Rise in tissue PCO2 and fall in PO2 stimulate peripheral chemoreceptors
• Ventilation rises proportionally to CO2 production during moderate exercise
• During intense exercise, lactic acidosis further stimulates ventilation

Metabolic Adjustments

• Increased O2 consumption (VO2); VO2max averages ~38 mL/kg/min in active men
• Local metabolic changes in muscle: fall in tissue PO2, rise in PCO2, accumulation of K+, lactate, H+, and vasodilator metabolites
• Temperature rises in active muscle, further dilating vessels
• 10-100x increase in open capillaries; average diffusion distance falls
• Blood mobilized from splanchnic reservoir; venous return increases via muscle pump and thoracic pump
• Training increases both maximal cardiac output and maximal O2 extraction

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Q2. Effects of Physical Training Under Heat & Cold Environment

Heat Environment

• Heat stress + exercise = competing demands on cardiovascular system: muscle needs blood flow for O2 delivery, skin needs blood flow for heat dissipation
• Core temperature rises; sweating and cutaneous vasodilation activated
• Plasma volume is reduced by heavy sweating, reducing stroke volume
• Heart rate rises more (to compensate for reduced stroke volume)
• Risk of heat exhaustion and heat stroke if thermoregulation fails
• Acclimatization to heat: plasma volume expands, sweating begins earlier and at lower core temp, sweat rate increases, electrolyte loss in sweat decreases
• Trained athletes tolerate heat better: higher sweat rates, earlier onset of sweating

Cold Environment

• Peripheral vasoconstriction to conserve core heat
• Blood is centrally redistributed; cardiac preload increases initially
• Heart rate may slow (cold effect on SA node); prolonged cold can cause cardiac arrhythmias
• Metabolic heat production increases (shivering thermogenesis, non-shivering thermogenesis via brown fat in infants)
• Exercise in cold: muscle cooling impairs contractile efficiency; VO2 may be higher for same workload
• Hypothermia risk if exercise intensity is low or clothing is wet
• Training in cold: acclimatization is less pronounced than for heat; vasoconstrictor responses may become attenuated with time

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Q3. Physiological Consequences of Sedentary Lifestyle

• Physical inactivity exacerbates age-related pathophysiologic changes
• Health consequences and societal costs are especially relevant to older adults
• VO2max (maximal oxygen consumption) is lower in sedentary individuals
• Risk of premature cardiovascular death is increased

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Q4. Physiology of Infancy

Cardiovascular

• Transition from fetal to adult circulation at birth (closure of ductus arteriosus, foramen ovale, ductus venosus)
• Heart rate is high (120-160 bpm); blood pressure is lower than adults
• Cardiac output is rate-dependent (cannot increase stroke volume as effectively)

Respiratory

• Respiratory rate is 30-60/min in newborns
• High oxygen consumption per kg body weight
• Obligate nose breathers initially; any obstruction causes respiratory distress
• Surfactant production begins at ~24-28 weeks; deficiency causes Respiratory Distress Syndrome (RDS)
• It takes up to 10 minutes for SpO2 to reach normal extrauterine levels after birth

Thermoregulation

• Inability to shiver to generate heat
• Large surface-area-to-volume ratio = excessive heat loss
• Poor fat stores, poor heat retention
• Brown fat (BAT) is major source of non-shivering thermogenesis
• Hypothermia rapidly leads to hypoglycemia and apnea

Metabolic / Glucose

• High metabolic rate; limited glycogen stores
• Immature hepatic enzymes increase hypoglycemia risk
• Hypoglycemia defined as blood glucose < 40 mg/dL in neonates
• Signs: apnea, seizures, lethargy, jitteriness

Growth & Development

• Rapid organ and CNS maturation in first year
• Brain reaches ~50% of adult size by 6 months, ~75% by 1 year
• Myelination progresses throughout infancy

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Q5. Basic Life Support (BLS) in Simulated Environments

Core BLS Steps (CAB - Compressions, Airway, Breathing)

1. Check safety of environment
2. Assess responsiveness - shout, tap
3. Call for help / activate emergency response
4. Chest compressions - rate 100-120/min, depth 5-6 cm (adults), allow full recoil
5. Airway - head-tilt chin-lift or jaw thrust
6. Rescue breaths - 2 breaths every 30 compressions (30:2 ratio)
7. AED use as soon as available - shock-advised rhythms: VF / pulseless VT

BLS in Special Environments

• High altitude / hypoxic environments: compressions are MORE important; rescue breaths may be less effective due to ambient hypoxia
• Cold environments: hypothermia can mimic death; "not dead until warm and dead" - continue CPR until rewarmed
• Aquatic environments: rescue breaths are given as soon as possible (drowning victims have hypoxic arrest primarily)
• Neonatal BLS (newborn): rate 120/min; 3:1 compression-to-ventilation ratio; bradycardia (HR < 100) = indicator of hypoxia and inadequate ventilation; vigorous stimulation for primary apnea, ventilation + compressions for secondary apnea

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REFORM: Doctor-Patient Relationship

Traditional (Paternalistic) Model

• Physician makes decisions for the patient ("doctor knows best")
• Patient is passive recipient of care
• Information was withheld if deemed harmful to patient's psyche

Modern (Informed Consent / Autonomy) Model

• Patient autonomy is central - right to make informed decisions
• Informed consent is mandatory: patient must be told diagnosis, treatment options, risks, benefits, alternatives
• Shared decision-making: physician and patient together decide on management
• Confidentiality: patient information is protected
• Non-maleficence and beneficence remain core duties

Key Ethical Principles

1. Autonomy - respect patient's right to decide
2. Beneficence - act in patient's best interest
3. Non-maleficence - do no harm
4. Justice - equitable care

Reform Drivers

• Patient rights movements
• Legal requirements (informed consent laws)
• Recognition that adherence improves with patient engagement
• Growing evidence that shared decision-making improves outcomes

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IMF PYQ (Previous Year Questions)

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PYQ 1: V/Q Ratio - Why Is It Higher at the Apex of the Lung?

Detailed Explanation

• Both ventilation (V) and perfusion (Q) are GREATER at the BASE than at the APEX
• However, the fall in blood flow from base to apex is PROPORTIONALLY GREATER than the fall in ventilation

• At start of inspiration, intrapleural pressure is LESS negative at the base than the apex
• At the apex, the lung is already MORE expanded (less stiffness reserve), so it accepts less additional volume per unit pressure
• Therefore, ventilation per unit volume is GREATER at the base

• Gravity causes the pulmonary arterial pressure to be lower at the apex
• In Zone 1 (apex): alveolar pressure may exceed pulmonary capillary pressure → capillaries collapse → minimal blood flow
• Blood flow at the base (Zone 3): both arterial and venous pressures exceed alveolar pressure → maximal flow

• Base: low V/Q ratio (~0.6) - relatively overperfused, underperfused
• Apex: high V/Q ratio (~3.0) - relatively well-ventilated, poorly perfused
• The relative change in blood flow from apex to base is greater than the relative change in ventilation, so V/Q is high at apex

• PO2 at apex = ~132 mmHg (high); PCO2 at apex = ~28 mmHg (low)
• PO2 at base = ~89 mmHg (low); PCO2 at base = ~42 mmHg (high)

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PYQ 2: Anthropometric Measurements to Assess Growth of Infant

Key Measurements

Growth Rules (Key Facts)

• Weight: doubles by 5 months, triples by 1 year, quadruples by 2 years
• Height: increases by ~25 cm in first year
• Head circumference > chest circumference at birth; they equalize at ~1 year
• Head circumference increases ~2 cm/month for first 3 months, then slows

Derived Indices

• Weight for Height (WHZ): detects acute malnutrition (wasting)
• Height for Age (HAZ): detects chronic malnutrition (stunting)
• Weight for Age (WAZ): general undernutrition
• BMI for age: overweight/obesity surveillance

Tools

• Growth charts (WHO Child Growth Standards, IAP charts)
• Z-scores and percentiles to compare with reference population
• MUAC tapes for field assessment of acute malnutrition

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PYQ 3: Hypoxia

Classification of Hypoxia (Guyton & Hall)

• Low inspired O2 (high altitude, enclosed spaces)
• Hypoventilation (neuromuscular disease, opioids, CNS depression)
• V/Q mismatch (COPD, asthma, pulmonary embolism)
• Diffusion defect (pulmonary fibrosis, pulmonary edema)
• Right-to-left cardiac shunt

• Anemia (reduced hemoglobin quantity)
• Carbon monoxide poisoning (CO binds Hb with 240x affinity)
• Methemoglobinemia (Fe2+ → Fe3+; cannot carry O2)

• Heart failure (generalized)
• Peripheral vascular disease (localized)
• Shock states

• Cyanide poisoning (blocks cytochrome oxidase)
• Severe sepsis
• Vitamin B deficiency (beriberi)

Effects of Hypoxia

• Impaired judgment and cognitive function
• Euphoria (early at high altitude)
• Tachycardia, tachypnea

• Headache, fatigue, dizziness
• Decreased muscle work capacity
• Cyanosis (when deoxy-Hb > 5 g/dL)

• Depressed mental activity → coma
• Cell death (especially brain: irreversible after 4-6 minutes)
• Cardiovascular collapse

Compensatory Responses to Hypoxia

1. Hyperventilation - hypoxic drive via peripheral chemoreceptors (carotid/aortic bodies)
2. Polycythemia - EPO secretion from kidney stimulates RBC production (chronic hypoxia)
3. Increased 2,3-DPG - shifts O2-Hb dissociation curve right (facilitates O2 release to tissues)
4. Angiogenesis - HIF-1α induced; new capillary formation
5. Pulmonary vasoconstriction - HPV (hypoxic pulmonary vasoconstriction) redirects blood to better-ventilated alveoli

Neonatal Hypoxia (BLS context)

• Primary apnea: responds to stimulation
• Secondary apnea: requires positive pressure ventilation ± chest compressions
• Bradycardia (HR < 100) is a key indicator of hypoxia in the newborn

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