Mechanical ventilation with high tidal volume induces inflammation in patients without lung disease

Roselaine Pinheiro De Oliveira,Gilberto Friedman,Daniele Dallegrave,Marcio Hetzel,Mauro Dos Anjos Silva

doi:10.1186/cc8919

Abstract

IntroductionMechanical ventilation (MV) with high tidal volumes may induce or aggravate lung injury in critical ill patients. We compared the effects of a protective versus a conventional ventilatory strategy, on systemic and lung production of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in patients without lung disease.MethodsPatients without lung disease and submitted to mechanical ventilation admitted to one trauma and one general adult intensive care unit of two different university hospitals were enrolled in a prospective randomized-control study. Patients were randomized to receive MV either with tidal volume (VT) of 10 to 12 ml/kg predicted body weight (high VT group) (n = 10) or with VT of 5 to 7 ml/kg predicted body weight (low VT group) (n = 10) with an oxygen inspiratory fraction (FIO2) enough to keep arterial oxygen saturation >90% with positive end-expiratory pressure (PEEP) of 5 cmH2O during 12 hours after admission to the study. TNF-α and IL-8 concentrations were measured in the serum and in the bronchoalveolar lavage fluid (BALF) at admission and after 12 hours of study observation time.ResultsTwenty patients were enrolled and analyzed. At admission or after 12 hours there were no differences in serum TNF-α and IL-8 between the two groups. While initial analysis did not reveal significant differences, standardization against urea of logarithmic transformed data revealed that TNF-α and IL-8 levels in bronchoalveolar lavage (BAL) fluid were stable in the low VT group but increased in the high VT group (P = 0.04 and P = 0.03). After 12 hours, BALF TNF-α (P = 0.03) and BALF IL-8 concentrations (P = 0.03) were higher in the high VT group than in the low VT group.ConclusionsThe use of lower tidal volumes may limit pulmonary inflammation in mechanically ventilated patients even without lung injury.Trial RegistrationClinical Trial registration: NCT00935896

Highlights

Mechanical ventilation (MV) with high tidal volumes may induce or aggravate lung injury in critical ill patients
The present study has shown that use of lower VT and positive end expiratory pressure (PEEP) might attenuate the pulmonary inflammatory response in near normal lungs
The major finding of the study is that both tumor necrosis factor-a (TNF-a) and IL-8 concentrations were increased with high VT but stable with low VT in the bronchoalveolar lavage (BAL) fluid in patients ventilated without lung disease after admission to an ICU

Summary

Introduction

Mechanical ventilation (MV) with high tidal volumes may induce or aggravate lung injury in critical ill patients. Clinical studies suggest that mechanical ventilation (MV) can modify inflammatory responses in patients with acute lung injury. In such patients, with existing pulmonary and systemic inflammation, ventilation with tidal volumes (VT) of 10 to 15 mL/kg predicted body weight and low-to-moderate levels of positive end expiratory pressure (PEEP) was associated with increased intraalveolar and systemic levels of inflammatory mediators [1]. Observational studies have showed that a lung inflammatory response could be induced after conventional and prolonged mechanical ventilation in a mixed population of critically ill patients [8,9]. Most studies used high VT and no PEEP in comparison to low VT and PEEP It is not known whether short-term mechanical ventilation with PEEP and moderate to high VT could induce signs of pulmonary or/and a systemic inflammation

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