*Extracted from comprehensive anesthesia notes.*
Preparatory Mindset
Focus on: physiologic effects of anesthesia, drug mechanisms, airway management, and complication recognition. Exam questions often test classification systems (ASA, airway assessment) and complication management.
Core Concepts
1. Fluid Therapy
Body Water Distribution
- • Adults: Water = 60% body weight
- • ICF: 40%; ECF: 20% (interstitial 15%, plasma 5%)
Key Point: Crystalloids ()
- • Small molecules, 25% intravascular (3 mL crystalloid ≈1 mL blood)
- • Half-life: 20–30 min
- • Normal Saline (0.9% NaCl): Cheap; risk of hyperchloremic acidosis
- • Lactated Ringer’s (LR): Balanced, preferred for resuscitation; avoid in hyperkalemia/renal failure
- • D5W: Free water; not for resuscitation
- • Large molecules, 70–100% intravascular; half-life: 3–6 h
- • Albumin: Safe, expensive
- • Gelatins: Lower allergy risk
- • HES: Risk of renal toxicity (restricted use)
- • Indications: Severe hypovolemia, hypoalbuminemia, burns
Key Point: Perioperative Fluid Calculation (4/2/1 Rule) ()
- • Maintenance: 4 mL/kg (1st 10 kg) + 2 mL/kg (11–20 kg) + 1 mL/kg (>20 kg)/h
- • Total Requirement: Preop deficit (4/2/1 × fasting h) + maintenance + surgical losses +
- unanticipated losses
- • Blood loss: 3 mL crystalloid or 1 mL colloid per 1 mL blood
- • Monitoring: Urine output 0.5–1 mL/kg/h, hemodynamics, electrolytes
High-Yield Points
- ASA classification is a must-know for exam
- Understand differences between general vs regional anesthesia
- Complications and their management are frequently tested
- Know the Mallampati score and airway assessment criteria