ORIGINAL ARTICLE DCO 2 /PaCO 2 correlation on high-frequency oscillatory ventilation combined with volume guarantee using increasing frequencies in an animal model Noelia González-Pacheco 1 & Manuel Sánchez-Luna 1 & Cristina Arribas-Sánchez 2 & Martín Santos-González 3 & Cristina Orden-Quinto 3 & Francisco Tendillo-Cortijo 3 Received: 14 May 2019 /Revised: 12 September 2019 /Accepted: 9 October 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract 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. Keywords High-frequency oscillatory ventilation . Volume guarantee . Ventilation efficiency . Lung injury Communicated by Patrick Van Reempts * Noelia González-Pacheco ngpacheco@salud.madrid.org Manuel Sánchez-Luna msluna@salud.madrid.org Cristina Arribas-Sánchez cristinaarribass@gmail.com Martín Santos-González martin.santos@salud.madrid.org Cristina Orden-Quinto cristinaordenq@gmail.com Francisco Tendillo-Cortijo franciscoj.tendillo@salud.madrid.org 1 Neonatology Division, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense de Madrid, Hospital General Universitario “Gregorio Marañón”, C/Dr. Esquerdo, 46, 28007 Madrid, Spain 2 Neonatology Division, Clínica Universidad de Navarra, C/ Marquesado de Sta. Marta, 1, 28027 Madrid, Spain 3 Medical and Surgical Research Unit, Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda, Hospital Universitario Puerta de Hierro-Majadahonda, C/Manuel de Falla, 1, 28222 Madrid, Spain European Journal of Pediatrics https://doi.org/10.1007/s00431-019-03503-8