Clinical studies

Among the many clinical studies on humidification, the following published articles support for the benefits of heated humidification with CPAP therapy:

• Rakotonanahary D, et al. Predictive factors for the need for additional humidification during nasal continuous positive airway pressure therapy. Chest 2001;119(2):460-465.
  This study identifies risk factors that may indicate a need for heated humidification: being older than 60 years; using drying medications; presence of chronic mucosa disease and previous uvulopalatopharyngoplasty (UPPP). It also demonstrated that heated humidification significantly improves CPAP daily use, while cold humidification did little.
  
• Martins De Araujo MT, Vieira SB, Vasquez EC, Fleury B. Heated humidification or face mask to prevent upper airway dryness during continuous positive airway pressure therapy. Chest 2000;117(1):142-147 Comment in: Chest 2000;117(3):617-9.
  This study found that the inhalation of dry air during CPAP therapy can be significantly lessened by heated humidification, even during mouth leaks, and can be totally prevented by using a full face mask.
  
• Massie CA, Hart RW, Peraliz K, Richards GN. Effects of humidification on nasal symptoms and compliance in sleep apnea patients using continuous positive airway pressure. Chest 1999;116(2):403-408.
  This study found that patients who use heated humidification were more compliant with CPAP and suggests that compliance may be realized sooner if patients are started with heated humidity at CPAP initiation.
  
• Richards GN, Cistulli PA, Ungar RG, Berthon-Jones M, Sullivan CE. Mouth leak with nasal continuous positive airway pressure increases nasal airway resistance. Am J Respir Crit Care Med 1996;154(1):182-186.
  This study demonstrated that nasal congestion, dry nose and sore throat affect approximately 40% of patients using nasal CPAP. Results also showed that heated humidification greatly decreased patient symptoms while cold passover did little.