Normocapnic high-frequency oscillatory ventilation affects differently extrapulmonary and pulmonary forms of acute respiratory distress syndrome in adults

Abstract

The recently reported differences between pulmonary and extrapulmonary acute respiratory distress syndromes (ARDS(p), ARDS(exp)) are the main reasons of scientific discussion on potential differences in the effects of current ventilatory strategies. The aim of this study is to assess whether the presence of ARDS(p) or ARDS(exp) can differently affect the beneficial effects of high-frequency oscillatory ventilation (HFOV) upon physiological and clinical parameters. Thirty adults fulfilling the ARDS criteria were indicated for HFOV in case of failure of conventional ventilation strategy. According to the ARDS type, each patient was included either in the group of patients with ARDS(p) or ARDS(exp). Six hours after normocapnic HFOV introduction, there was no significant increase in PaO2/F(I)O2 in ARDS(p) group (from 129+/-47 to 133+/-50 Torr), but a significant improvement was found in ARDS(exp) (from 114+/-54 to 200+/-65 Torr, p<0.01). Despite the insignificant difference in the latest mean airway pressure (MAP) on conventional mechanical ventilation (CMV) between both groups, initial optimal continuous distension pressure (CDP) for the best PaO2/F(I)O2 during HFOV was 2.0+/-0.6 kPa in ARDS(p) and 2.8+/-0.6 kPa in ARDS(exp) (p<0.01). HFOV recruits and thus it is more effective in ARDS(exp). ARDS(exp) patients require higher CDP levels than ARDS(p) patients. The testing period for positive effect of HFOV is recommended not to be longer than 24 hours.

Electrical Impedance Tomography Can Be Used to Quantify Lung Hyperinflation during HFOV: The Pilot Study in Pigs

“…As an independent method for confirmation of dynamic hyperinflation or hypoinflation existence, a chest X-ray was used during the measurements. As tidal volumes and pressure amplitudes in the alveolar space during HFOV are very small in comparison with conventional mechanical ventilation [ 25 , 26 , 27 , 28 ], the diaphragm do not move significantly during HFOV breathing cycles, and therefore there is no need for a synchronization of the X-ray imaging with a certain phase of the breathing cycle.…”

The Physiological Basis of High-Frequency Oscillatory Ventilation and Current Evidence in Adults and Children: A Narrative Review

“…Early case series of HFOV in adults reported improvements in oxygenation with variable effects on hemodynamics ( Fort et al, 1997 ; Claridge et al, 1999 ; Mehta et al, 2001 ). Subsequent studies confirmed these results, but most enrolled less than 50 subjects ( Fort et al, 1997 ; Claridge et al, 1999 ; Mehta et al, 2001 ; Andersen et al, 2002 ; David et al, 2003 ; Mehta et al, 2004 ; Ferguson et al, 2005 ; Finkielman et al, 2006 ; Pachl et al, 2006 ; Fessler et al, 2008 ; Kao et al, 2011 ; Niwa et al, 2011 ; Camporota et al, 2013 ; Jog et al, 2013 ; Naorungroj et al, 2015 ; Thind et al, 2021 ). HFOV has also been described in three small case series of burn patients involving 6 to 30 subjects with mortality between 32 and 83% ( Cartotto et al, 2001 ; Cartotto et al, 2004 ; Cartotto et al, 2009 ).…”

Tidal volume significantly affects oxygenation in healthy pigs during high-frequency oscillatory ventilation compared to conventional ventilation

“…When the authors started to use HFOV in adult patients with acute respiratory distress syndrome (ARDS) more than 15 years ago, they used a custom-made respiratory monitor for the measurement of V T delivered during HFOV [ 13 , 14 ]. It was noticed that V T during HFOV was not only important for the control of CO 2 elimination but that V T affected oxygenation as well, even if mean airway pressure was kept constant.…”