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Effect of low tidal volume ventilation on lung function and inflammation in mice.

Hauber HP, Karp D, Goldmann T, Vollmer E, Zabel P - BMC Pulm Med (2010)

Bottom Line: Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05).These effects were not statistically significant (P > 0.05).Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Pathophysiology of Inflammation, Research Center Borstel, Borstel, Germany. hphauber@fz-borstel.de

ABSTRACT

Background: A large number of studies have investigated the effects of high tidal volume ventilation in mouse models. In contrast data on very short term effects of low tidal volume ventilation are sparse. Therefore we investigated the functional and structural effects of low tidal volume ventilation in mice.

Methods: 38 Male C57/Bl6 mice were ventilated with different tidal volumes (Vt 5, 7, and 10 ml/kg) without or with application of PEEP (2 cm H2O). Four spontaneously breathing animals served as controls. Oxygen saturation and pulse rate were monitored. Lung function was measured every 5 min for at least 30 min. Afterwards lungs were removed and histological sections were stained for measurement of infiltration with polymorphonuclear leukocytes (PMN). Moreover, mRNA expression of macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)alpha in the lungs was quantified using real time PCR.

Results: Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05). Pulse rate dropped in all groups without PEEP during mechanical ventilation. In contrast, in the groups with PEEP pulse rate increased over time. These effects were not statistically significant (P > 0.05). Tissue damping (G) and tissue elastance (H) were significantly increased in all groups after 30 min of ventilation (P < 0.05). Only the group with a Vt of 10 ml/kg and PEEP did not show a significant increase in H (P > 0.05). Mechanical ventilation significantly increased infiltration of the lungs with PMN (P < 0.05). Expression of MIP-2 was significantly induced by mechanical ventilation in all groups (P < 0.05). MIP-2 mRNA expression was lowest in the group with a Vt of 10 ml/kg + PEEP.

Conclusions: Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally. Formation of atelectasis and inadequate oxygenation with very low tidal volumes may be important factors. Application of PEEP attenuated inflammation.

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Histological sections of lung parenchyma after mechanical ventilation with different tidal volumes without and with application of PEEP. HE staining. Original magnification ×400.
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Figure 4: Histological sections of lung parenchyma after mechanical ventilation with different tidal volumes without and with application of PEEP. HE staining. Original magnification ×400.

Mentions: Ventilation without PEEP significantly increased the numbers of polymorphonuclear leukocytes (PMN) at all used tidal volumes (Vt 5 ml/kg: 28.7 ± 2.4 cells/field, Vt 7 ml/kg: 34.9 ± 4.3 cells/field, and Vt 10 ml/kg: 36.8 ± 4.9 cells/field) compared to spontaneously breathing mice (20.0 ± 2.5 cells/field) (P < 0.05) (Fig 3). With addition of PEEP the numbers of PMN were reduced but were still significantly increased in ventilated mice (Vt 5 ml/kg: 25.5 ± 0.6 cells/field, Vt 7 ml/kg: 26.8 ± 2.1 cells/field, and Vt 10 ml/kg: 31.7 ± 3.2 cells/field) compared to spontaneously breathing mice (P < 0.05). Fig 4 shows original histology section stained with HE of the eight different ventilation groups. Infiltration of intraalveolar septae with PMN is noted with all applied ventilation protocols.


Effect of low tidal volume ventilation on lung function and inflammation in mice.

Hauber HP, Karp D, Goldmann T, Vollmer E, Zabel P - BMC Pulm Med (2010)

Histological sections of lung parenchyma after mechanical ventilation with different tidal volumes without and with application of PEEP. HE staining. Original magnification ×400.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864238&req=5

Figure 4: Histological sections of lung parenchyma after mechanical ventilation with different tidal volumes without and with application of PEEP. HE staining. Original magnification ×400.
Mentions: Ventilation without PEEP significantly increased the numbers of polymorphonuclear leukocytes (PMN) at all used tidal volumes (Vt 5 ml/kg: 28.7 ± 2.4 cells/field, Vt 7 ml/kg: 34.9 ± 4.3 cells/field, and Vt 10 ml/kg: 36.8 ± 4.9 cells/field) compared to spontaneously breathing mice (20.0 ± 2.5 cells/field) (P < 0.05) (Fig 3). With addition of PEEP the numbers of PMN were reduced but were still significantly increased in ventilated mice (Vt 5 ml/kg: 25.5 ± 0.6 cells/field, Vt 7 ml/kg: 26.8 ± 2.1 cells/field, and Vt 10 ml/kg: 31.7 ± 3.2 cells/field) compared to spontaneously breathing mice (P < 0.05). Fig 4 shows original histology section stained with HE of the eight different ventilation groups. Infiltration of intraalveolar septae with PMN is noted with all applied ventilation protocols.

Bottom Line: Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05).These effects were not statistically significant (P > 0.05).Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Pathophysiology of Inflammation, Research Center Borstel, Borstel, Germany. hphauber@fz-borstel.de

ABSTRACT

Background: A large number of studies have investigated the effects of high tidal volume ventilation in mouse models. In contrast data on very short term effects of low tidal volume ventilation are sparse. Therefore we investigated the functional and structural effects of low tidal volume ventilation in mice.

Methods: 38 Male C57/Bl6 mice were ventilated with different tidal volumes (Vt 5, 7, and 10 ml/kg) without or with application of PEEP (2 cm H2O). Four spontaneously breathing animals served as controls. Oxygen saturation and pulse rate were monitored. Lung function was measured every 5 min for at least 30 min. Afterwards lungs were removed and histological sections were stained for measurement of infiltration with polymorphonuclear leukocytes (PMN). Moreover, mRNA expression of macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)alpha in the lungs was quantified using real time PCR.

Results: Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05). Pulse rate dropped in all groups without PEEP during mechanical ventilation. In contrast, in the groups with PEEP pulse rate increased over time. These effects were not statistically significant (P > 0.05). Tissue damping (G) and tissue elastance (H) were significantly increased in all groups after 30 min of ventilation (P < 0.05). Only the group with a Vt of 10 ml/kg and PEEP did not show a significant increase in H (P > 0.05). Mechanical ventilation significantly increased infiltration of the lungs with PMN (P < 0.05). Expression of MIP-2 was significantly induced by mechanical ventilation in all groups (P < 0.05). MIP-2 mRNA expression was lowest in the group with a Vt of 10 ml/kg + PEEP.

Conclusions: Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally. Formation of atelectasis and inadequate oxygenation with very low tidal volumes may be important factors. Application of PEEP attenuated inflammation.

Show MeSH
Related in: MedlinePlus