DCO2/PaCO2 correlation on high-frequency oscillatory ventilation combined with volume guarantee using increasing frequencies in an animal model

• Published in: European journal of pediatrics 2020-03, Vol.179 (3), p.499-506
• Main Authors: González-Pacheco, Noelia, Sánchez-Luna, Manuel, Arribas-Sánchez, Cristina, Santos-González, Martín, Orden-Quinto, Cristina, Tendillo-Cortijo, Francisco
• Format: Article
• Language: English
• Subjects: Alveoli; Animal models; Blood pressure; Bronchus; Carbon dioxide; Diffusion coefficient; Efficiency; Gas exchange; Mechanical ventilation; Medicine; Medicine & Public Health; Neonates; Original Article; Pediatrics; Respiratory system; Respiratory therapy; Ventilators
• ISSN: 0340-6199; 1432-1076
• DOI: 10.1007/s00431-019-03503-8

To examine the correlation DCO 2 /PaCO 2 on high-frequency oscillatory ventilation (HFOV) combined with volume guarantee (VG) throughout increasing frequencies in two different respiratory conditions, physiological and low compliance. Neonatal animal model was used, before and after a bronchoalveolar lavage (BAL). HFOV combined with VG was used. The frequency was increased from 10 to 20 Hz, and high-frequency tidal volume (VThf) was gradually decreased maintaining a constant DCO 2 . Arterial partial pressure of carbon dioxide (PaCO 2 ) was evaluated after each frequency and VThf change. Six 2-day-old piglets were studied. A linear decrease in PaCO 2 was observed throughout increasing frequencies in both respiratory conditions while maintaining a constant DCO 2 , showing a significant difference between the initial PaCO 2 (at 10 Hz) and the PaCO 2 obtained at 18 and 20 Hz. A new DCO 2 equation (corrected DCO 2 ) was calculated in order to better define the correlation between DCO 2 and the observed PaCO 2 . Conclusion : The correlation DCO 2 /PaCO 2 throughout increasing frequencies is not linear, showing a greater CO 2 elimination efficiency at higher frequencies, in spite of maintaining a constant DCO 2 . So, using frequencies close to the resonant frequency of the respiratory system on HFOV combined with VG, optimizes the efficiency of gas exchange. What is Known: • The efficacy of CO 2 removal during high-frequency oscillatory ventilation (HFOV), described as the diffusion coefficient of CO 2 (DCO 2 ) is related to the square of the high-frequency tidal volume (VThf) and the frequency (f), expressed as DCO 2 = VThf 2 × f. What is New: • The correlation between DCO 2 and PaCO 2 throughout increasing frequencies is not linear, showing a greater CO 2 elimination efficiency at higher frequencies. So, using very high frequencies on HFOV combined with volume guarantee optimizes the efficiency of gas exchange allowing to minimize lung injury.