Models of PaO<sub>2</sub>response to the continuous distending pressure maneuver during high frequency oscillatory ventilation in healthy and ARDS lung model pigs

Laviola, Marianna; Ráfl, Jakub; Rožánek, Martin; Kudrna, Petr; Roubík, Karel

doi:10.3109/01902148.2016.1145307

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…The shape of the curve of PaO 2 with increased MAP steps in our study is similar to that found in other reports using surfactant deficiency models 31,32 . In both cases, the intensity of the change in PaO 2 levels after MAP modifications, instead of the absolute PaO 2, value was considered as a lung recruitment marker.…”

Section: Discussionsupporting

confidence: 87%

New indicators for optimal lung recruitment during high frequency oscillator ventilation

Blanca

Luna

González‐Pacheco

et al. 2020

Pediatric Pulmonology

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Previous research has demonstrated the potential benefit derived from the combination of high frequency oscillatory ventilation and volume guarantee mode (HFOV‐VG), a procedure that allows us to explore and control very low tidal volumes. We hypothesized that secondary spontaneous change in oscillation pressure amplitude (∆Phf), while increasing the mean airway pressure (MAP) using HFOV‐VG can target the lung recruitment. Methods A two‐step animal distress model study was designed; in the first‐step (ex vivo model), the animal's lungs were isolated to visually check lung recruitment and, in the second one (in vivo model), they were checked through arterial oxygen partial pressure improvement. Baseline measurements were performed, ventilation was set for 10 min and followed by bronchoalveolar lavage with isotonic saline to induce depletion of surfactant and thereby achieve a low compliance lung model. The high‐frequency tidal volume and frequency remained constant and the MAP was increased by 2 cmH2O (ex vivo) and 3 cmH2O steps (in vivo) every 2 min. Changes in ΔPhf to achieve the fixed volume were recorded at the end of each interval to describe the maximum drop point as the recruitment point. Results Fourteen Wistar Han rats were included, seven on each sub‐study described. After gradual MAP increments, a progressive decrease in ΔPhf related to recruited lung regions was visually demonstrated. In the in vivo model we detected a significant comparative decrease of ΔPhf, when measured against the previous value, after reaching a MAP of 11 cmH2O up to 17 cmH2O, correlating with a significant improvement in oxygenation. Conclusion The changes in ∆Phf, linked to a progressive increase in MAP during HFOV‐VG, might identify optimal lung recruitment and could potentially be used as an additional lung recruitment marker.

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Section: Discussionsupporting

confidence: 87%

New indicators for optimal lung recruitment during high frequency oscillator ventilation

Blanca

Luna

González‐Pacheco

et al. 2020

Pediatric Pulmonology

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“…Previously, we also reported that RIP may be of additional value during pediatric HFOV [15]. In our present study, we found that oxygenation improved not only in responsive, but also unresponsive lung volume optimization maneuvers, challenging if oxygenation is a good bedside marker for lung volume changes as also has been observed during CMV [28,29]. It has also been proposed that a decrease in blood pressure might be perceived as sign of lung overdistension and may thus be used as a parameter guiding the lung volume optimization maneuver.…”

Section: Discussionsupporting

confidence: 70%

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

Jager

Burgerhof

Koopman

et al. 2020

Ann. Intensive Care

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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.

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“…An example of such a maneuver, and thus a possible advantage of using the relative compliance determination, is optimizing CDP in the initial phase of HFOV or its reassessment during the course of ventilation. Another advantage of relative compliance determination could be evaluating efficiency of recruitment maneuver, commonly implemented as a stepwise increase and consequent decrease of CDP, while evaluating influenced physiological parameters [42]. In these situations, when a constant airway inertance and resistance can be assumed, observing a short-time trend of relative compliance gives a faster response than standard methods that utilize assessment of the respiratory gas exchange.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2021

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High-frequency oscillatory ventilation (HFOV), which uses a small tidal volume and a high respiratory rate, is considered a type of protective lung ventilation that can be beneficial for certain patients. A disadvantage of HFOV is its limited monitoring of lung mechanics, which complicates its settings and optimal adjustment. Recent studies have shown that respiratory system reactance (Xrs) could be a promising parameter in the evaluation of respiratory system mechanics in HFOV. The aim of this study was to verify in vitro that a change in respiratory system mechanics during HFOV can be monitored by evaluating Xrs. We built an experimental system consisting of a 3100B high-frequency oscillatory ventilator, a physical model of the respiratory system with constant compliance, and a system for pressure and flow measurements. During the experiment, models of different constant compliance were connected to HFOV, and Xrs was derived from the impedance of the physical model that was calculated from the spectral density of airway opening pressure and spectral cross-power density of gas flow and airway opening pressure. The calculated Xrs changed with the change of compliance of the physical model of the respiratory system. This method enabled monitoring of the trend in the respiratory system compliance during HFOV, and has the potential to optimize the mean pressure setting in HFOV in clinical practice.

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Models of PaO₂response to the continuous distending pressure maneuver during high frequency oscillatory ventilation in healthy and ARDS lung model pigs

Abstract: The PaO2 curve may give information about the level of recruitment of alveoli, but cannot be used for optimization of CDP level during HFOV in healthy and ARDS lung model pigs.

Cited by 6 publications

References 12 publications

New indicators for optimal lung recruitment during high frequency oscillator ventilation

New indicators for optimal lung recruitment during high frequency oscillator ventilation

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

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

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Models of PaO2response to the continuous distending pressure maneuver during high frequency oscillatory ventilation in healthy and ARDS lung model pigs

Abstract: The PaO2 curve may give information about the level of recruitment of alveoli, but cannot be used for optimization of CDP level during HFOV in healthy and ARDS lung model pigs.

Cited by 6 publications

References 12 publications

New indicators for optimal lung recruitment during high frequency oscillator ventilation

New indicators for optimal lung recruitment during high frequency oscillator ventilation

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

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

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Models of PaO₂response to the continuous distending pressure maneuver during high frequency oscillatory ventilation in healthy and ARDS lung model pigs