High frequency oscillation ventilation compared to conventional mechanical ventilation plus exogenous surfactant replacement in rabbits

Piva, Jefferson Pedro; Chatrkaw, Phornlert; Choong, Karen; Frndova, Helena; Cox, Peter N.

doi:10.2223/jped.73

Cited by 3 publications

(5 citation statements)

References 28 publications

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“…Overdistension caused by increased airway pressure in CMV can be avoided when HFOV is used, preventing alveolar derecruitment and oscillations in alveolar volume (collapse and re-expansion), saving surfactant and decreasing local inflammation. 34 HFOV has shown consistent beneficial results in clinical and experimental ARDS. 11,15,24,35 In accordance with previous reports, our study confirmed that HFOV improved oxygenation, and reduced inflammatory and histopathological injuries.…”

Section: Discussionmentioning

confidence: 81%

“…17 Patients with ALI or ARDS ventilated at 6 mL/kg V T had a significant reduction in mortality compared with those ventilated at higher traditional V T . This concept leads to an interest in HFOV 24 as it uses a very small V T and constant 34 HFOV has shown consistent beneficial results in clinical and experimental ARDS. 11,15,24,35 In accordance with previous reports, our study confirmed that HFOV improved oxygenation, and reduced inflammatory and histopathological injuries.…”

Section: Discussionmentioning

confidence: 99%

“…Similar results have been observed by others. 11,17,34,39 While there are many studies evaluating the effects of HFOV on oxygenation, lung inflammation and histological injury in animal ALI models, only a few have analyzed oxidative stress. 11,18 Furthermore, to our knowledge, there is no study available on the effects of HFOV on lung oxidative status determined by TAP assay in pulmonary tissue.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

Ronchi

Ferreira²,

Campos³

et al. 2011

Exp Biol Med (Maywood)

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Mechanical ventilation (MV) can induce lung oxidative stress, which plays an important role in pulmonary injury. This study compared protective conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation (HFOV) for oxygenation, oxidative stress, inflammatory and histopathological lung injury in a rabbit model of acute lung injury (ALI). Rabbits (n = 30) were ventilated at FiO(2) 1.0. Lung injury was induced by tracheal saline infusion (30 mL/kg, 38°C). Animals were randomly assigned to: (a) sham control (CG: tidal volume [V(T)] 6 mL/kg, positive end expiratory pressure [PEEP] 5 cmH(2)O, respiratory rate [RR] 40 ipm); (b) ALI + CMV (CMVG: V(T) 6 mL/kg, PEEP 10 cmH(2)O, RR 40 ipm); or (c) ALI + HFOV (HFG: mean airway pressure [Paw] 14 cmH(2)O, RR 10 Hz) groups. Lung oxidative stress was assessed by total antioxidant performance assay, inflammatory response by the number of polymorphonuclear leukocytes/bronchoalveolar lavage fluid/lung and pulmonary histological damage was quantified by a score. Ventilatory and hemodynamic parameters were recorded every 30 min. Both ALI groups showed worse oxygenation after lung injury induction. After four hours of ventilation, HFG showed better oxygenation (partial pressure of oxygen [PaO(2)] - CG: 465.9 ± 30.5 = HFG: 399.1 ± 98.2 > CMVG: 232.7 ± 104 mmHg, P < 0.05) and inflammatory responses (CMVG: 4.27 ± 1.50 > HFG: 0.33 ± 0.20 = CG: 0.16 ± 0.15; polymorphonuclear cells/bronchoalveolar lavage fluid/lung, P < 0.05), less histopathological injury score (CMVG: 5 [1-16] > HFG: 1 [0-5] > CG: 0 [0-3]; P < 0.05), and lower lung oxidative stress than CMVG (CG: 59.4 ± 4.52 = HFG: 69.0 ± 4.99 > CMVG: 47.6 ± 2.58% protection/g protein, P < 0.05). This study showed that HFOV had an important protective role in ALI. It improved oxygenation, reduced inflammatory process and histopathological damage, and attenuated oxidative lung injury compared with protective CMV under these experimental conditions considering the study limitations.

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Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

Ronchi

Ferreira²,

Campos³

et al. 2011

Exp Biol Med (Maywood)

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“…1). We have previously observed that V T and ventilator frequency were closely related by measuring V T in animals ventilated at 5 and 15 Hz (26). Therefore, 5 Hz HFOV may have generated higher V T than 15 Hz HFOV, which, together with data from other experiments, suggests an inverse relationship between V T and ventilation frequency, whereby the former increases with decreasing ventilator fre- (4,27).…”

mentioning

confidence: 67%

Protective Strategies of High-Frequency Oscillatory Ventilation in a Rabbit Model

et al. 2006

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High-frequency oscillatory ventilation (HFOV) causes less severe lung injury than conventional mechanical ventilation (CMV) but the optimal frequency for HFOV has not been determined. We hypothesized that 15 Hz HFOV would be more protective than 5 Hz HFOV in a rabbit model of acute lung injury. Surfactant-depleted rabbits were ventilated at 15 Hz or 5 Hz HFOV for 4 h, or not ventilated, to characterize the extent of lung injury before HFOV. PaO 2 and PaCO 2 were measured throughout the experiment, and lung myeloperoxidase (MPO) activity, neutrophil infiltration, and histopathological changes were determined. There were no statistically significant differences in PaO 2 and PaCO 2 between groups (p Ͼ 0.05). Neutrophil counts (p ϭ 0.013), airway injury scores (p ϭ 0.007), airspace injury scores (p ϭ 0.029), and total lung injury scores (p ϭ 0.014) differed between non-HFOventilated and HFOV animals. Comparing the 2 HFOV regimens, 15 Hz ventilation yielded a lower tissue neutrophil score (p ϭ 0.005). MPO activity, neutrophil count, airway injury score, airspace injury score, and total lung injury score parameters did not differ significantly between the HFOV groups (p Ͼ 0.150). We concluded that both frequencies of HFOV efficiently restored O 2 and CO 2 exchange in a rabbit model of severe lung injury, and that 5 Hz HFOV increased neutrophil infiltration relative to 15 Hz HFOV. I ntensive care physicians generally agree that conventional mechanical ventilation (CMV), with relatively large tidal volumes (V T ) or low positive end expiratory pressure (PEEP) levels, contributes to ventilator associated lung injury (VALI) in patients with acute respiratory distress syndrome (ARDS) (1). Convective bulk flow is believed to be the means by which gas is moved from the proximal airways to the alveoli in this form of ventilation with large volume excursions of the lung as a consequence. The mechanisms by which gas is delivered to the distal airspaces in high-frequency oscillatory ventilation (HFOV) differ from those of CMV, in that volumes smaller than dead space are moved within the lung during ventilation (2,3). The protective benefit gained through HFOV is believed to be due to a reduction in expansion and contraction of the small airways and airspaces. Although HFOV is considered protective in nature, it remains undetermined whether all frequencies of HFOV are equally protective.The relationship of V T to frequency (f) is approximated by the formula: DCO 2 ␣ V T 2 f (where DCO 2 represents CO 2 elimination) during HFOV (3,4). From this relationship it is clear that if CO 2 were to be maintained at constant normocapneic levels, then a lower frequency would result in a higher V T . The high V T potentially increases delta V and lung distension, and likely leads to VALI, possibly by a mechanism similar to that of convectional bulk airflow in CMV. In contrast, the higher the frequency, the lower the V T and the bulk flow, and the less distension of the small airways and airspaces will occur. Until recently, due to t...

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Utilization of the Lower Inflection Point of the Pressure-Volume Curve Results In Protective Conventional Ventilation Comparable to High Frequency Oscillatory Ventilation in an Animal Model of Acute Respiratory Distress Syndrome

Rossi

Mascaretti

Haddad

et al. 2008

Clinics

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aRossi FS, Mascaretti RS, Haddad LB, Freddi NA, Mauad T, Rebello CM. Utilization of the lower inflection point of the pressure-volume curve results in protective conventional ventilation comparable to high frequency oscillatory ventilation in an animal model of acute respiratory distress syndrome. Clinics. 2008;63:237-44. INTRODUCTION:Studies comparing high frequency oscillatory and conventional ventilation in acute respiratory distress syndrome have used low values of positive end-expiratory pressure and identified a need for better recruitment and pulmonary stability with high frequency. OBJECTIVE: To compare conventional and high frequency ventilation using the lower inflection point of the pressure-volume curve as the determinant of positive end-expiratory pressure to obtain similar levels of recruitment and alveolar stability. METHODS: After lung lavage of adult rabbits and lower inflection point determination, two groups were randomized: conventional (positive end-expiratory pressure = lower inflection point; tidal volume=6 ml/kg) and high frequency ventilation (mean airway pressures= lower inflection point +4 cmH 2 O). Blood gas and hemodynamic data were recorded over 4 h. After sacrifice, protein analysis from lung lavage and histologic evaluation were performed. RESULTS: The oxygenation parameters, protein and histological data were similar, except for the fact that significantly more normal alveoli were observed upon protective ventilation. High frequency ventilation led to lower PaCO 2 levels. DISCUSSION: Determination of the lower inflection point of the pressure-volume curve is important for setting the minimum end expiratory pressure needed to keep the airways opened. This is useful when comparing different strategies to treat severe respiratory insufficiency, optimizing conventional ventilation, improving oxygenation and reducing lung injury. CONCLUSIONS: Utilization of the lower inflection point of the pressure-volume curve in the ventilation strategies considered in this study resulted in comparable efficacy with regards to oxygenation and hemodynamics, a high PaCO 2 level and a lower pH. In addition, a greater number of normal alveoli were found after protective conventional ventilation in an animal model of acute respiratory distress syndrome.

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High frequency oscillation ventilation compared to conventional mechanical ventilation plus exogenous surfactant replacement in rabbits

Cited by 3 publications

References 28 publications

High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

Protective Strategies of High-Frequency Oscillatory Ventilation in a Rabbit Model

Utilization of the Lower Inflection Point of the Pressure-Volume Curve Results In Protective Conventional Ventilation Comparable to High Frequency Oscillatory Ventilation in an Animal Model of Acute Respiratory Distress Syndrome

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