Physiologic responses to a staircase lung volume optimization maneuver in pediatric high-frequency oscillatory ventilation

Abstract

Background Titration of the continuous distending pressure during a staircase incremental–decremental pressure lung volume optimization maneuver in children on high-frequency oscillatory ventilation is traditionally driven by oxygenation and hemodynamic responses, although validity of these metrics has not been confirmed. Methods Respiratory inductance plethysmography values were used construct pressure–volume loops during the lung volume optimization maneuver. The maneuver outcome was evaluated by three independent investigators and labeled positive if there was an increase in respiratory inductance plethysmography values at the end of the incremental phase. Metrics for oxygenation (SpO2, FiO2), proximal pressure amplitude, tidal volume and transcutaneous measured pCO2 (ptcCO2) obtained during the incremental phase were compared between outcome maneuvers labeled positive and negative to calculate sensitivity, specificity, and the area under the receiver operating characteristic curve. Ventilation efficacy was assessed during and after the maneuver by measuring arterial pH and PaCO2. Hemodynamic responses during and after the maneuver were quantified by analyzing heart rate, mean arterial blood pressure and arterial lactate. Results 41/54 patients (75.9%) had a positive maneuver albeit that changes in respiratory inductance plethysmography values were very heterogeneous. During the incremental phase of the maneuver, metrics for oxygenation and tidal volume showed good sensitivity (> 80%) but poor sensitivity. The sensitivity of the SpO2/FiO2 ratio increased to 92.7% one hour after the maneuver. The proximal pressure amplitude showed poor sensitivity during the maneuver, whereas tidal volume showed good sensitivity but poor specificity. PaCO2 decreased and pH increased in patients with a positive and negative maneuver outcome. No new barotrauma or hemodynamic instability (increase in age-adjusted heart rate, decrease in age-adjusted mean arterial blood pressure or lactate > 2.0 mmol/L) occurred as a result of the maneuver. Conclusions Absence of improvements in oxygenation during a lung volume optimization maneuver did not indicate that there were no increases in lung volume quantified using respiratory inductance plethysmography. Increases in SpO2/FiO2 one hour after the maneuver may suggest ongoing lung volume recruitment. Ventilation was not impaired and there was no new barotrauma or hemodynamic instability. The heterogeneous responses in lung volume changes underscore the need for monitoring tools during high-frequency oscillatory ventilation.

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

“…These results may help to explain the HFOV-related controversies after two large HFOV clinical studies OSCAR [ 20 ] and OSCILLATE [ 21 ] as well as the consequential analyses and review articles were published. Recent studies demonstrated that HFOV requires an individual approach when setting the ventilator [ 22 , 23 ] and the lack of the individual approach to HFOV settings could have affected the outcome of the earlier large studies [ 24 , 25 ]. Both in pediatric [ 26 ] and adult patients [ 27 ] HFOV needs to be applied on a case-by-case basis for which a better understanding of HFOV is required.…”

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

“…The reported mortality for different PARDS severity was similar to the mortality reported in the PARDIE study ( Khemani et al, 2019 ). A different report from the same group found minimal hemodynamic effects, with 88% sensitivity and 54% specificity for changes in lung volumes ( de Jager et al, 2020 ). This is the HFOV strategy currently being investigated as part of the PROSPECT trial ( https://prospect-network.org/ ).…”

“…Thus, the use of high mPaw during HFOV may be detrimental to RV function due to increased PVR. Available data, however, do not show significant hemodynamic effects during stepwise recruitment and de-recruitment maneuvers ( de Jager et al, 2020 ). Additionally, the elevated mPaw used during HFOV may adversely affect preload and result in the need for intravascular fluid expansion that can lead to volume overload.…”

In Vitro Estimation of Relative Compliance during High-Frequency Oscillatory Ventilation

“…The optimal management of HFOV, including CDP, which would be based on knowledge of lung mechanics of the patient, is unresolved, which could have contributed to inconsistent or negative conclusions of large multicenter HFOV studies [9,10] and subsequent meta-analyses [11,12]. Recent studies have shown that an individual approach to HFOV settings could improve the patient's outcome [13,14]. Other Appl.…”