316.3 🏥 內科專科考前版

316.3.1 Mechanistic Deep Dive

316.3.1.1 Stress-Strain Concept

  • Pulmonary stress = transpulmonary pressure
  • Strain = Vt / FRC ratio
  • High stress + strain → VILI
  • Esophageal pressure monitoring for accurate transpulmonary

316.3.1.2 Driving Pressure

  • Plateau - PEEP
  • Reflects lung mechanics + Vt selection
  • Amato 2015: < 15 best survival
  • More predictive than Vt or plateau

316.3.1.3 Diaphragm Function + Ventilator

  • Diaphragm atrophy within hours of MV
  • Critical illness ICUAW
  • Strategies to preserve: minimize sedation + paralysis, partial support modes
  • Phrenic nerve stimulation (RESCUE-3 trial)

316.3.2 Recent Trials & Updates

316.3.2.1 MENDS-2 (2024)

  • Dexmedetomidine vs propofol in ARDS
  • Equivalent outcomes
  • Less delirium with dex
  • Sedation strategy

316.3.2.2 PRO-ICU Trial

  • Open lung ventilation strategies
  • Personalized approach

316.3.2.3 PreMixD (2024)

  • Pre-extubation strategies

316.3.2.4 COVID-PRONE + HENI-COVID

  • Awake prone in non-intubated COVID
  • Mixed results
  • Implementation variable

316.3.2.5 Permissive Hypercapnia + Cerebral

  • Caution in TBI, ICP elevation
  • Otherwise OK

316.3.3 High-Yield Specialist Points

316.3.3.1 Ventilator Asynchrony Types

  • Trigger asynchrony: missed triggers, double triggers
  • Flow asynchrony: inadequate flow
  • Cycle asynchrony: short / long inspiration
  • Reverse trigger: ventilator-triggered diaphragm
  • Detection + correction important

316.3.3.2 Diaphragm Ultrasound

  • Bedside thickness + function
  • Predicts weaning success
  • Diaphragm-protective ventilation

316.3.3.3 Awake Proning Indications

  • Hypoxemic respiratory failure
  • COVID-19 era widespread
  • Position 1-2 hours BID-TID
  • May reduce intubation
  • Variable evidence

316.3.3.4 Lung Recruitment

  • High-frequency mucus mobilization
  • Saline insufflation
  • Recruitment maneuver (mixed evidence ART trial)

316.3.3.5 Helium-Oxygen (Heliox)

  • For severe upper airway obstruction
  • ↓ Work of breathing
  • Limited evidence in ARDS

316.3.3.6 Inhaled Pulmonary Vasodilators

  • iNO, prostacyclin
  • Improve oxygenation
  • No mortality benefit
  • Rescue therapy

316.3.3.7 Extubation Failure Prediction

  • Cough peak flow > 60 L/min
  • Adequate mental status (RASS ≥ -1)
  • Hemodynamic stability
  • SBT success

316.3.3.8 Cuff Leak Test

  • Pre-extubation
  • Predicts post-extubation stridor
  • ≀ 110 mL cuff leak: increased risk
  • Steroids 24 hours pre-extubation if positive

316.3.3.9 Tracheostomy Care

  • Suctioning every 4-6 hours
  • Tube changes
  • Speaking valve (Passy-Muir)
  • Decannulation criteria
  • Infection prevention

316.3.3.10 Long-Term Outcomes Post-MV

  • PICS (post-intensive care syndrome)
  • Functional decline
  • Cognitive impairment
  • PTSD, depression
  • Multidisciplinary follow-up

316.3.4 Pearls

  • Lung-protective: Vt 6 mL/kg PBW + plateau < 30 + driving pressure < 15
  • Sedation strategy: light sedation + SAT + SBT daily
  • Dexmedetomidine (MENDS-2): less delirium than propofol
  • NIV: COPD exacerbation pH < 7.35 (Class I); cardiogenic edema
  • HFNC (FLORALI 2015): comparable to NIV
  • VAP: 7-day course; empiric → narrow
  • Tracheostomy: prolonged MV > 14 days
  • Awake proning: COVID era; mixed evidence
  • ICUAW + diaphragm weakness: limit sedation + paralysis; early mobility