Abstract
Crit Care Sci. 2023;35(4):386-393
DOI 10.5935/2965-2774.20230190-pt
To assess the effect of atelectasis during mechanical ventilation on the periatelectatic and normal lung regions in a model of atelectasis in rats with acute lung injury induced by lipopolysaccharide.
Twenty-four rats were randomized into the following four groups, each with 6 animals: the Saline-Control Group, Lipopolysaccharide Control Group, Saline-Atelectasis Group, and Lipopolysaccharide Atelectasis Group. Acute lung injury was induced by intraperitoneal injection of lipopolysaccharide. After 24 hours, atelectasis was induced by bronchial blocking. The animals underwent mechanical ventilation for two hours with protective parameters, and respiratory mechanics were monitored during this period. Thereafter, histologic analyses of two regions of interest, periatelectatic areas and the normally-aerated lung contralateral to the atelectatic areas, were performed.
The lung injury score was significantly higher in the Lipopolysaccharide Control Group (0.41 ± 0.13) than in the Saline Control Group (0.15 ± 0.51), p < 0.05. Periatelectatic regions showed higher lung injury scores than normally-aerated regions in both the Saline-Atelectasis (0.44 ± 0.06 x 0.27 ± 0.74 p < 0.05) and Lipopolysaccharide Atelectasis (0.56 ± 0.09 x 0.35 ± 0.04 p < 0.05) Groups. The lung injury score in the periatelectatic regions was higher in the Lipopolysaccharide Atelectasis Group (0.56 ± 0.09) than in the periatelectatic region of the Saline-Atelectasis Group (0.44 ± 0.06), p < 0.05.
Atelectasis may cause injury to the surrounding tissue after a period of mechanical ventilation with protective parameters. Its effect was more significant in previously injured lungs.
Abstract
Rev Bras Ter Intensiva. 2020;32(1):108-114
DOI 10.5935/0103-507X.20200016
To examine the effectiveness of stratification to identify and target antioxidant therapy for animal models of lethal sepsis and in patients who develop sustained hypotension.
Rats were subjected to sepsis induced by cecal ligation and puncture. Animals were divided into two groups: those with high and low plasma levels of interleukin-6. Following stratification, N-acetylcysteine plus deferoxamine or saline was administered to animals starting 3 and 12 hours after surgery. N-Acetylcysteine plus deferoxamine or placebo was administered within 12 hours of meeting the inclusion criteria in hypotensive patients.
N-Acetylcysteine plus deferoxamine increased survival in the cecal ligation and puncture model when administered 3 and 12 hours after sepsis induction. When dividing animals that received antioxidants using plasma interleukin-6 levels, the protective effect was observed only in those animals with high IL-6 levels. The antioxidant effect of N-acetylcysteine + deferoxamine was similar in the two groups, but a significant decrease in plasma interleukin-6 levels was observed in the high-interleukin-6-level group. Compared with patients treated with antioxidants in the low-interleukin-6 subgroup, those in the high-interleukin-6 subgroup had a lower incidence of acute kidney injury but were not different in terms of acute kidney injury severity or intensive care unit mortality.
Targeting antioxidant therapy to a high inflammatory phenotype would select a responsive population.