Variable Ventilation Associated With Recruitment Maneuver Minimizes Tissue Damage and Pulmonary Inflammation in Anesthetized Lung-Healthy Rats

Camilo, Luciana Moisés; Ribeiro, Gabriel; Avila, Mariana B.; Paula, Luís Felipe; Abreu, Maria Helena; Carvalho, Alysson R.; Zin, Walter A.

doi:10.1213/ane.0000000000003582

Cited by 8 publications

(6 citation statements)

References 28 publications

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“…A number of mathematically derived variable ventilation patterns have been investigated previously. These patterns relied on different statistical distributions of V T , such as Gaussian (Kiss et al, 2016; Wierzchon et al, 2017; Camilo et al, 2018; Guldner et al, 2018; Spieth et al, 2018), white noise (Froehlich et al, 2008; Guldner et al, 2018), or skewed (Thammanomai et al, 2008; Bartolak-Suki et al, 2017). In the present study, we decided to apply the latter as this particular pattern was designed specifically to optimize lung recruitment in a murine model of acute lung injury (Thammanomai et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…The selection of the animal model might also warrant some methodological considerations. While previous studies investigating variable mechanical ventilation in animals used large mammals, such as pigs or sheep (Mutch et al, 2000; Boker et al, 2002; Funk et al, 2004; Bellardine et al, 2006; Spieth et al, 2009) or small rodents, i.e., mice or rats (Thammanomai et al, 2008, 2013; Kiss et al, 2016; Camilo et al, 2018), our protocol utilized a rabbit model. There are widely accepted differences in tidal volume and respiratory rate, which are mainly attributed to be effects of body size (Bide et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Among novel ventilation modalities, application of a variable V T and/or frequency has been proposed to enhance alveolar recruitment thereby optimizing lung aeration and gas exchange (Suki et al, 1998; Vassilakopoulos and Zakynthinos, 2008). The variability in V T in these previous studies was defined by various statistical distributions, including Gaussian normal (Kiss et al, 2016; Wierzchon et al, 2017; Camilo et al, 2018; Guldner et al, 2018; Spieth et al, 2018) or skewed probability density distributions (Thammanomai et al, 2008; Bartolak-Suki et al, 2017). In an attempt to extend this approach, we recently developed a variable ventilation modality based on a pre-recorded physiological breathing pattern (Walesa et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS

Fodor¹,

Bayat²,

Albu³

et al. 2019

Front. Physiol.

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Background Introducing mathematically derived variability (MVV) into the otherwise monotonous conventional mechanical ventilation has been suggested to improve lung recruitment and gas exchange. Although the application of a ventilation pattern based on variations in physiological breathing (PVV) is beneficial for healthy lungs, its value in the presence of acute respiratory distress syndrome (ARDS) has not been characterized. We therefore aimed at comparing conventional pressure-controlled ventilation with (PCS) or without regular sighs (PCV) to MVV and PVV at two levels of positive end-expiratory pressure (PEEP) in a model of severe ARDS. Methods Anesthetised rabbits ( n = 54) were mechanically ventilated and severe ARDS (PaO 2 /FiO 2 ≤ 150 mmHg) was induced by combining whole lung lavage, i.v. endotoxin and injurious ventilation. Rabbits were then randomly assigned to be ventilated with PVV, MVV, PCV, or PCS for 5 h while maintaining either 6 or 9 cmH 2 O PEEP. Ventilation parameters, blood gas indices and respiratory mechanics (tissue damping, G, and elastance, H) were recorded hourly. Serum cytokine levels were assessed with ELISA and lung histology was analyzed. Results Although no progression of lung injury was observed after 5 h of ventilation at PEEP 6 cmH 2 O with PVV and PCV, values for G (58.8 ± 71.1[half-width of 95% CI]% and 40.8 ± 39.0%, respectively), H (54.5 ± 57.2%, 50.7 ± 28.3%), partial pressure of carbon-dioxide (PaCO 2 , 43.9 ± 23.8%, 46.2 ± 35.4%) and pH (−4.6 ± 3.3%, −4.6 ± 2.2%) worsened with PCS and MVV. Regardless of ventilation pattern, application of a higher PEEP improved lung function and precluded progression of lung injury and inflammation. Histology lung injury scores were elevated in all groups with no difference between groups at either PEEP level. Conclusion At moderate PEEP, variable ventilation based on a pre-recorded physiological breathing pattern protected against progression of lung injury equally to the conventional pressure-controlled mode, whereas mathematical variability or application of regular sighs caused worsening in lung mechanics. This outcome may be related to the excessive increases in peak inspiratory pressure with the latter ventilation modes. However, a greater benefit on respiratory mechanics and gas exchange could be obtained by elevating PEEP, compared to the ventilation mode in severe ARDS.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS

Fodor¹,

Bayat²,

Albu³

et al. 2019

Front. Physiol.

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“…23 In contrast, reduced lung damage has been observed in small animals ventilated with variable ventilation compared with conventional ventilation in hydrochloric acid injured 24 and noninjured lungs. 5,25 In pigs with saline lung lavaged lungs, the histologic damage, but not the level of cytokines, was reduced during variable ventilation compared with nonvariable ventilation when PEEP was !12 cm H 2 O. 6 In contrast, variable ventilation worsened epithelial cell damage when combined with higher PEEP levels, 24 whereas we opted for the use of the ARDS Network 7 low PEEP table, which represents current clinical practice.…”

Section: Discussionmentioning

confidence: 99%

Effects of variable versus nonvariable controlled mechanical ventilation on pulmonary inflammation in experimental acute respiratory distress syndrome in pigs

Wittenstein

Scharffenberg

Braune

et al. 2020

British Journal of Anaesthesia

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Background: Mechanical ventilation with variable tidal volumes (V T ) may improve lung function and reduce ventilatorinduced lung injury in experimental acute respiratory distress syndrome (ARDS). However, previous investigations were limited to less than 6 h, and control groups did not follow clinical standards. We hypothesised that 24 h of mechanical ventilation with variable V T reduces pulmonary inflammation (as reflected by neutrophil infiltration), compared with standard protective, nonvariable ventilation. Methods: Experimental ARDS was induced in 14 anaesthetised pigs with saline lung lavage followed by injurious mechanical ventilation. Pigs (n¼7 per group) were randomly assigned to using variable V T or nonvariable V T modes of mechanical ventilation for 24 h. In both groups, ventilator settings including positive end-expiratory pressure and oxygen inspiratory fraction were adjusted according to the ARDS Network protocol. Pulmonary inflammation (primary endpoint) and perfusion were assessed by positron emission tomography using 2-deoxy-2-[ 18 F]fluoro-D-glucose and 68 Gallium ( 68 Ga)-labelled microspheres, respectively. Gas exchange, respiratory mechanics, and haemodynamics were quantified. Lung aeration was determined using CT. Results: The specific global uptake rate of 18 F-FDG increased to a similar extent regardless of mode of mechanical ventilation (median uptake for variable V T ¼0.016 min À1 [inter-quartile range, 0.012e0.029] compared with median uptake for nonvariable V T ¼0.037 min À1 [0.008e0.053]; P¼0.406). Gas exchange, respiratory mechanics, haemodynamics, and lung aeration and perfusion were similar in both variable and nonvariable V T ventilatory modes. Conclusion:In a porcine model of ARDS, 24 h of mechanical ventilation with variable V T did not attenuate pulmonary inflammation compared with standard protective mechanical ventilation with nonvariable V T .

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“…In recent years, it has been advocated that mechanical ventilation reproducing the natural variability of breathing is better than conventional modes [ 9 , 10 ]. Variable ventilation has been shown to be beneficial for gas exchange and respiratory mechanics in various animal models with healthy [ 11 – 13 ] or injured lungs, including ARDS [ 14 – 17 ]. We have previously established a variable ventilation modality using pre-recorded breathing patterns of healthy animals [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Physiologically variable ventilation reduces regional lung inflammation in a pediatric model of acute respiratory distress syndrome

et al. 2020

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Background Benefits of variable mechanical ventilation based on the physiological breathing pattern have been observed both in healthy and injured lungs. These benefits have not been characterized in pediatric models and the effect of this ventilation mode on regional distribution of lung inflammation also remains controversial. Here, we compare structural, molecular and functional outcomes reflecting regional inflammation between PVV and conventional pressure-controlled ventilation (PCV) in a pediatric model of healthy lungs and acute respiratory distress syndrome (ARDS). Methods New-Zealand White rabbit pups (n = 36, 670 ± 20 g [half-width 95% confidence interval]), with healthy lungs or after induction of ARDS, were randomized to five hours of mechanical ventilation with PCV or PVV. Regional lung aeration, inflammation and perfusion were assessed using x-ray computed tomography, positron-emission tomography and single-photon emission computed tomography, respectively. Ventilation parameters, blood gases and respiratory tissue elastance were recorded hourly. Results Mechanical ventilation worsened respiratory elastance in healthy and ARDS animals ventilated with PCV (11 ± 8%, 6 ± 3%, p < 0.04), however, this trend was improved by PVV (1 ± 4%, − 6 ± 2%). Animals receiving PVV presented reduced inflammation as assessed by lung normalized [18F]fluorodeoxyglucose uptake in healthy (1.49 ± 0.62 standardized uptake value, SUV) and ARDS animals (1.86 ± 0.47 SUV) compared to PCV (2.33 ± 0.775 and 2.28 ± 0.3 SUV, respectively, p < 0.05), particularly in the well and poorly aerated lung zones. No benefit of PVV could be detected on regional blood perfusion or blood gas parameters. Conclusions Variable ventilation based on a physiological respiratory pattern, compared to conventional pressure-controlled ventilation, reduced global and regional inflammation in both healthy and injured lungs of juvenile rabbits.

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Variable Ventilation Associated With Recruitment Maneuver Minimizes Tissue Damage and Pulmonary Inflammation in Anesthetized Lung-Healthy Rats

Abstract: Variable ventilation was more protective than conventional ventilation within the applied PEEP levels.

Cited by 8 publications

References 28 publications

Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS

Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS

Effects of variable versus nonvariable controlled mechanical ventilation on pulmonary inflammation in experimental acute respiratory distress syndrome in pigs

Physiologically variable ventilation reduces regional lung inflammation in a pediatric model of acute respiratory distress syndrome

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