High frequency percussive ventilation increases alveolar recruitment in early acute respiratory distress syndrome: an experimental, physiological and CT scan study

Abstract

BackgroundHigh frequency percussive ventilation (HFPV) combines diffusive (high frequency mini-bursts) and convective ventilation patterns. Benefits include enhanced oxygenation and hemodynamics, and alveolar recruitment, while providing hypothetic lung-protective ventilation. No study has investigated HFPV-induced changes in lung aeration in patients with early acute respiratory distress syndrome (ARDS).MethodsEight patients with early non-focal ARDS were enrolled and five swine with early non-focal ARDS were studied in prospective computed tomography (CT) scan and animal studies, in a university-hospital tertiary ICU and an animal laboratory. Patients were optimized under conventional “open-lung” ventilation. Lung CT was performed using an end-expiratory hold (Conv) to assess lung morphology. HFPV was applied for 1 hour to all patients before new CT scans were performed with end-expiratory (HFPV EE) and end-inspiratory (HFPV EI) holds. Lung volumes were determined after software analysis. At specified time points, blood gases and hemodynamic data were collected. Recruitment was defined as a change in non-aerated lung volumes between Conv, HFPV EE and HFPV EI. The main objective was to verify whether HFPV increases alveolar recruitment without lung hyperinflation. Correlation between pleural, upper airways and HFPV-derived pressures was assessed in an ARDS swine-based model.ResultsOne-hour HFPV significantly improved oxygenation and hemodynamics. Lung recruitment significantly rose by 12.0% (8.5–18.0%), P = 0.05 (Conv-HFPV EE) and 12.5% (9.3–16.8%), P = 0.003 (Conv-HFPV EI). Hyperinflation tended to increase by 2.0% (0.5–2.5%), P = 0.89 (Conv-HFPV EE) and 3.0% (2.5–4.0%), P = 0.27 (Conv-HFPV EI). HFPV hyperinflation correlated with hyperinflated and normally-aerated lung volumes at baseline: r = 0.79, P = 0.05 and r = 0.79, P = 0.05, respectively (Conv-HFPV EE); and only hyperinflated lung volumes at baseline: r = 0.88, P = 0.01 (Conv-HFPV EI). HFPV CT-determined tidal volumes reached 5.7 (1.1–8.1) mL.kg-1 of ideal body weight (IBW). Correlations between pleural and HFPV-monitored pressures were acceptable and end-inspiratory pleural pressures remained below 25cmH20.ConclusionsHFPV improves alveolar recruitment, gas exchanges and hemodynamics of patients with early non-focal ARDS without relevant hyperinflation. HFPV-derived pressures correlate with corresponding pleural or upper airways pressures.Trial registrationClinicalTrials.gov, NCT02510105. Registered on 1 June 2015. The trial was retrospectively registered.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1924-6) contains supplementary material, which is available to authorized users.

High-frequency percussive ventilation in acute respiratory distress syndrome: knocking at the door but can it be let in?

“…HFPV was governed according to a predefined protocol and continued until patients could be switched to conventional ventilation. Essentially, our results corroborate the findings of Godet et al [ 2 ]. Within 24 h, oxygenation improved to a similar proportion (i.e., doubling of the PaO 2 /FiO 2 ratio).…”

“…According to Godet et al [ 2 ], HFPV perfectly fits within the “Open the Lung and Keep it Open” concept of protective lung ventilation in ARDS. Applying HFPV, however, differs considerably from a low tidal volume/high positive end-expiratory pressure (PEEP) ventilation strategy where personalizing the PEEP level is primordial to minimize dynamic strain caused by alveolar recruitment/derecruitment [ 4 ].…”

“…Godet et al [ 2 ] recently documented the effects of short-term application of high-frequency percussive ventilation (HFPV) in animals and patients with early nonfocal moderate to severe ARDS. HFPV highly improved oxygenation and hemodynamics.…”

“…HFPV highly improved oxygenation and hemodynamics. In addition, HFPV allowed significant alveolar recruitment without concomitant hyperinflation of aerated lung regions [ 2 ]. Based on their observations, the authors suggested further investigation of HFPV on patient outcome during ARDS.…”

Multi-scale convolutional neural networks for segmentation of pulmonary structures in computed tomography

“…CT imaging is increasingly being used to characterize the spatial heterogeneity of injury and regional mechanics of ARDS [65,103,38,44,102,14]. Quantitative CT (qCT) enables objective quantification of injury and has been used for evaluating response to mechanical ventilation protocols [9,51,104] and monitoring injury progression [16,15]. Spatial and temporal heterogeneity of ventilation in ARDS can be measured through registration of dynamically imaged lungs [58] or lungs imaged at multiple inflation levels [65,103,15].…”