High-Tidal-Volume Mechanical Ventilation and Lung Inflammation in Intensive Care Patients With Normal Lungs

Abstract

Background This study was conducted to investigate whether high-tidal-volume mechanical ventilation is associated with increased lung inflammation compared with low-tidal-volume mechanical ventilation in critically ill patients with no evidence of lung injury. Methods In this prospective, single-blind, randomized (1:1), parallel-group study, 18 critically ill patients with normal lungs were randomly assigned to receive mechanical ventilation with a tidal volume of either 6 mL/kg (low tidal volume) or 12 mL/kg (high tidal volume) during the first 4 days in the intensive care unit. Results At baseline and at 24, 48, and 96 hours, exhaled breath condensate was collected to measure interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites. Interleukin 1β levels in exhaled breath condensate were significantly increased at 24 hours compared with baseline in the high-tidal-volume group but not in the low-tidal-volume group. The interleukin 1β increase in the high-tidal-volume group was transient. Exhaled breath condensate levels of interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites did not differ significantly between the high-tidal-volume and low-tidal-volume groups at any time point. Conclusion Short-term mechanical ventilation with a tidal volume of 12 mL/kg may trigger inflammatory responses in the lungs of intensive care unit patients without preexisting lung injury.