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hypercapneic respiratory failure

acute & chronic forms Etiology: - COPD - asthma - restrictive lung disease - chest wall musculoskeletal disorders - obesity - depressed respiratory drive - opioids - sedatives Pathology: - alveolar ventilation is inadequate resulting in an increase in pCO2 - since blood oxygenation depends on alveolar ventilation, patients are often hypoxic* * the hypoxia improves with supplemental oxygen Clinical manifestations: - in patients with respiratory muscle weakness & obesity-hypoventilation syndrome first hypoventilate during REM sleep. Laboratory: - arterial blood gas for pCO2 Special laboratory: - pulmonary function testing - evaluation of maximum inspiratory pressures & expiratory pressures & changes in vital capacity with changes in position helpful to assess role of neuromuscular weakness - with neuromuscular weakness - DLCO is normal - > 20 decline in FVC in supine position vs upright position - maximal inspiratory pressure < -60 cm H20 or < 50% of predicted - maximal expiratory pressure < +60 cm H20 or < 50% of predicted - polysomnography if nocturnal hypoventilation is suspected - daytime sleepiness, nocturnal awakenings, morning headaches Management: - non-invasive positive-pressure ventilation is superior to high-flow nasal cannula in patients with moderate hypercapnic respiratory failure during COPD exacerbation [2]

Specific

acute hypercapneic respiratory failure chronic hypercapneic respiratory failure

General

respiratory failure

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 19 American College of Physicians, Philadelphia 2022 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Tan D, Wang B, Cao P et al. High flow nasal cannula oxygen therapy versus non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease with acute-moderate hypercapnic respiratory failure: A randomized controlled non-inferiority trial. Crit Care 2024 Jul 18; 28:250. PMID: 39026242 PMCID: PMC11264824 Free PMC article https://ccforum.biomedcentral.com/articles/10.1186/s13054-024-05040-9