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Egyptian Board Thoracic Diseases study materials
Egyptian Board Thoracic Diseases study resources

Egyptian Board Thoracic Diseases: Respiratory Critical Care and Mechanical Ventilation

Egyptian Board Thoracic Diseases · Work through your exam, one topic at a time.

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Respiratory Critical Care and Mechanical Ventilation

Domain 9 - Respiratory Critical Care and Mechanical Ventilation

This domain tests recognition and management of acute respiratory failure, ARDS, sepsis and ventilator-associated problems. The Board expects lung-protective ventilation settings, plateau pressure targets, prone positioning and safe weaning.

Core rules

  • ARDS Berlin definition: acute onset within 1 week, bilateral opacities not fully explained by effusion, collapse or nodules, respiratory failure not fully explained by cardiac failure, and PaO₂/FiO₂ ≤300 mmHg on PEEP ≥5 cmH₂O. Mild 200–300, moderate 100–200, severe <100.
  • Lung-protective ventilation: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH₂O, driving pressure ≤15 cmH₂O, and appropriate PEEP. Permissive hypercapnia is acceptable.
  • Prone positioning for ≥16 hours/day improves survival in moderate-severe ARDS. Neuromuscular blockade may be considered in early severe ARDS. ECMO is reserved for refractory hypoxaemia after optimisation.
  • COPD exacerbation with respiratory acidosis: NIV reduces intubation and mortality. Asthma with exhaustion or altered consciousness requires intubation; NIV is not routine.
  • Weaning: assess readiness daily, perform spontaneous breathing trial, and extubate if tolerated. Use cuff-leak test when prolonged intubation or stridor risk is present.

Worked example

A 170 cm man with pneumonia has PaO₂ 60 mmHg on FiO₂ 0.50 and PEEP 10 cmH₂O. PaO₂/FiO₂ is 120, so he has moderate ARDS. Predicted body weight is 50 + 0.91(170 − 152.4) = 66 kg; set tidal volume 6 × 66 = 396 mL. Plateau pressure is 28 cmH₂O, so ventilation is lung-protective. Prone positioning is indicated for at least 16 hours daily. Do not increase tidal volume to normalise PaCO₂; permissive hypercapnia is acceptable if pH is safe.

Traps that cost marks

  • Setting tidal volume by actual body weight in obese patients.
  • Accepting plateau pressure >30 cmH₂O.
  • Using high PEEP without assessing haemodynamics and barotrauma.
  • Routine NIV in severe asthma or ARDS outside COPD.
  • Extubating without a spontaneous breathing trial.

Key points

  • ARDS: PaO₂/FiO₂ ≤300 on PEEP ≥5; moderate 100–200.
  • Tidal volume 6 mL/kg predicted body weight; plateau ≤30 cmH₂O.
  • Prone position for ≥16 h/day in moderate-severe ARDS.
  • NIV is evidence-based in COPD exacerbation with acidosis.
  • Daily spontaneous breathing trial guides extubation.