Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow

Cristiane Sousa Nascimento Baez Garcia, Soraia Carvalho Abreu, Roberta Soares, Luiz Felipe Mancilha Prota, Rogério Cruz Figueira, Marcelo Marcos Morales, Vera Luiza Capelozzi, Walter Araújo Zin, Patricia Rieken Macedo Rocco

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

OBJECTIVE: Uncertainties about the numerous degrees of freedom in ventilator settings leave many unanswered questions about the biophysical determinants of lung injury. We investigated whether mechanical ventilation with high air flow could yield lung mechanical stress even in normal animals. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University research laboratory. SUBJECTS: Thirty normal male Wistar rats (180-230 g). INTERVENTIONS: Rats were ventilated for 2 hrs with tidal volume of 10 mL/kg and either with normal inspiratory air flow (V′) of 10 mL/s (F10) or high V′ of 30 mL/s (F30). In the control group, animals did not undergo mechanical ventilation. Because high flow led to elevated respiratory rate (200 breaths/min) and airway peak inspiratory pressure (PIP,aw = 17 cm H2O), two additional groups were established to rule out the potential contribution of these variables: a) normal respiratory rate = 100 breaths/min and V′ = 30 mL/sec; and b) PIP,aw = 17 cm H2O and V′ = 10 mL/sec. MEASUREMENTS AND MAIN RESULTS: Lung mechanics and histology (light and electron microscopy), arterial blood gas analysis, and type III procollagen messenger RNA expression in lung tissue were analyzed. Ultrastructural microscopy was similar in control and F10 groups. High air flow led to increased lung plateau and peak pressures, hypoxemia, alveolar hyperinflation and collapse, pulmonary neutrophilic infiltration, and augmented type III procollagen messenger RNA expression compared with control rats. The reduction of respiratory rate did not modify the morphofunctional behavior observed in the presence of increased air flow. Even though the increase in peak pressure yielded mechanical and histologic changes, type III procollagen messenger RNA expression remained unaltered. CONCLUSIONS: Ventilation with high inspiratory air flow may lead to high tensile and shear stresses resulting in lung functional and morphologic compromise and elevation of type III procollagen messenger RNA expression.

Original languageEnglish (US)
Pages (from-to)232-239
Number of pages8
JournalCritical Care Medicine
Volume36
Issue number1
DOIs
StatePublished - Jan 1 2008
Externally publishedYes

Fingerprint

Artificial Respiration
Collagen Type III
Air
Lung
Respiratory Rate
Messenger RNA
Pressure
Control Groups
Blood Gas Analysis
Mechanical Stress
Tidal Volume
Lung Injury
Mechanical Ventilators
Mechanics
Uncertainty
Ventilation
Wistar Rats
Microscopy
Histology
Electron Microscopy

Keywords

  • Alveolar damage
  • Extracellular matrix
  • Shear stress
  • Ventilator-induced lung injury

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

Cite this

Nascimento Baez Garcia, C. S., Abreu, S. C., Soares, R., Mancilha Prota, L. F., Figueira, R. C., Morales, M. M., ... Macedo Rocco, P. R. (2008). Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow. Critical Care Medicine, 36(1), 232-239. https://doi.org/10.1097/01.CCM.0000295309.69123.AE

Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow. / Nascimento Baez Garcia, Cristiane Sousa; Abreu, Soraia Carvalho; Soares, Roberta; Mancilha Prota, Luiz Felipe; Figueira, Rogério Cruz; Morales, Marcelo Marcos; Capelozzi, Vera Luiza; Zin, Walter Araújo; Macedo Rocco, Patricia Rieken.

In: Critical Care Medicine, Vol. 36, No. 1, 01.01.2008, p. 232-239.

Research output: Contribution to journalArticle

Nascimento Baez Garcia, CS, Abreu, SC, Soares, R, Mancilha Prota, LF, Figueira, RC, Morales, MM, Capelozzi, VL, Zin, WA & Macedo Rocco, PR 2008, 'Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow', Critical Care Medicine, vol. 36, no. 1, pp. 232-239. https://doi.org/10.1097/01.CCM.0000295309.69123.AE
Nascimento Baez Garcia CS, Abreu SC, Soares R, Mancilha Prota LF, Figueira RC, Morales MM et al. Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow. Critical Care Medicine. 2008 Jan 1;36(1):232-239. https://doi.org/10.1097/01.CCM.0000295309.69123.AE
Nascimento Baez Garcia, Cristiane Sousa ; Abreu, Soraia Carvalho ; Soares, Roberta ; Mancilha Prota, Luiz Felipe ; Figueira, Rogério Cruz ; Morales, Marcelo Marcos ; Capelozzi, Vera Luiza ; Zin, Walter Araújo ; Macedo Rocco, Patricia Rieken. / Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow. In: Critical Care Medicine. 2008 ; Vol. 36, No. 1. pp. 232-239.
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AU - Mancilha Prota, Luiz Felipe

AU - Figueira, Rogério Cruz

AU - Morales, Marcelo Marcos

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