BACKGROUND: The role of high-frequency oscillatory ventilation (HFOV) has long been debated. Numerous studies documented its benefits, whereas several more recent studies did not prove superiority of HFOV over protective conventional mechanical ventilation (CV). One of the accepted explanations is that CV and HFOV act differently, including gas exchange. METHODS: To investigate a different level of coupling or decoupling between oxygenation and carbon dioxide elimination during CV and HFOV, we conducted a prospective crossover animal study in 11 healthy pigs. In each animal, we found a normocapnic tidal volume (VT) after the lung recruitment maneuver. Then, VT was repeatedly changed over a wide range while keeping constant the levels of PEEP during CV and mean airway pressure during HFOV. Arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were recorded. The same procedure was repeated for CV and HFOV in random order. RESULTS: Changes in PaCO2 intentionally induced by adjustment of VT affected oxygenation more significantly during HFOV than during CV. Increasing VT above its normocapnic value during HFOV caused a significant improvement in oxygenation, whereas improvement in oxygenation during CV hyperventilation was limited. Any decrease in VT during HFOV caused a rapid worsening of oxygenation compared to CV. CONCLUSION: A change in PaCO2 induced by the manipulation of tidal volume inevitably brings with it a change in oxygenation, while this effect on oxygenation is significantly greater in HFOV compared to CV.

• Keywords
• High-frequency oscillatory ventilation, Mechanical ventilation, Oxygenation, Tidal volume,
• MeSH
• Tidal Volume MeSH
• Lung MeSH
• Swine MeSH
• Prospective Studies MeSH
• Pulmonary Gas Exchange * MeSH
• High-Frequency Ventilation * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

The main goal of our prospective randomized study was comparing compare the effectiveness of ventilation control method "Automatic proportional minute ventilation (APMV) "versus manually set pressure control ventilation modes in relationship to lung mechanics and gas exchange. 80 patients undergoing coronary artery bypass grafting (CABG) were randomized into 2 groups. 40 patients in the first group No.1 (APMV group) were ventilated with pressure control (PCV) or pressure support ventilation (PSV) mode with APMV control. The other 40 patients (control group No.2) were ventilated with synchronized intermittent mandatory ventilation (SIMV-p) or pressure control modes (PCV) without APMV. Ventilation control with APMV was able to maintain minute ventilation more precisely in comparison with manual control (p<0.01), similarly deviations of ETCO(2) were significantly lower (p<0.01). The number of manual corrections of ventilation settings was significantly lower when APMV was used (p<0.01). The differences in lung mechanics and hemodynamics were not statistically significant. Ventilation using APMV is more precise in maintaining minute ventilation and gas exchange compared with manual settings. It required less staff intervention, while respiratory system mechanics and hemodynamics are comparable. APMV showed as effective and safe method applicable on top of all pressure control ventilation modes.

• MeSH
• Hemodynamics physiology   MeSH
• Coronary Artery Bypass methods   MeSH
• Middle Aged MeSH
• Humans MeSH
• Respiratory Mechanics physiology   MeSH
• Prospective Studies MeSH
• Aged MeSH
• Respiration, Artificial methods   MeSH
• Positive-Pressure Respiration methods   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH