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- Nyberg, Axel, et al.
(författare)
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Lung-protective ventilation suppresses systemic and hepatic vein levels of cell-free DNA in porcine experimental post-operative sepsis
- 2020
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Ingår i: BMC Pulmonary Medicine. - : Springer Science and Business Media LLC. - 1471-2466. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Plasma levels of cell-free DNA (cf-DNA) are known to be elevated in sepsis and high levels are associated with a poor prognosis. Mechanical ventilation affects systemic inflammation in which lung-protective ventilation attenuates the inflammatory response. The aim was to study the effect of a lung protective ventilator regime on arterial and organ-specific venous blood as well as on trans-organ differences in cf-DNA levels in a porcine post-operative sepsis model. Method One group of anaesthetised, domestic-breed, 9-12 weeks old, pigs were ventilated with protective ventilation (V(T)6 mL x kg(- 1), PEEP 10 cmH(2)O)n = 20. Another group, ventilated with a medium high tidal volume and lower PEEP, served as a control group (V(T)10 mL x kg(- 1), PEEP 5 cm H2O)n = 10. Blood samples were taken from four sources: artery, hepatic vein, portal vein and, jugular bulb. A continuous endotoxin infusion at 0.25 mu g x kg(- 1)x h(- 1)for 5 h was started following 2 h of laparotomy, which simulated a surgical procedure. Inflammatory cytokines and cf-DNA in plasma were analysed and trans-organ differences calculated. Results The protective ventilation group had lower levels of cf-DNA in arterial (p = 0.02) and hepatic venous blood (p = 0.03) compared with the controls. Transhepatic differences in cf-DNA were lower in the protective group, compared with the controls (p = 0.03). No differences between the groups were noted as regards the transcerebral, transsplanchnic or the transpulmonary cf-DNA differences. Conclusions Protective ventilation suppresses arterial levels of cf-DNA. The liver seems to be a net contributor to the systemic cf-DNA levels, but this effect is attenuated by protective ventilation.
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| 2. |
- Sperber, Jesper, et al.
(författare)
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Pre-exposure to mechanical ventilation and endotoxemia increases Pseudomonas aeruginosa growth in lung tissue during experimental porcine pneumonia
- 2020
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immune system suppression during critical care contributes to the risk of acquired bacterial infections with Pseudomonas (P.) aeruginosa. Repeated exposure to endotoxin can attenuate systemic inflammatory cytokine responses. Mechanical ventilation affects the systemic inflammatory response to various stimuli.Aim: To study the effect of pre-exposure to mechanical ventilation with and without endotoxin-induced systemic inflammation on P. aeruginosa growth and wet-to-dry weight measurements on lung tissue and plasma and bronchoalveolar lavage levels of tumor necrosis factor alpha, interleukins 6 and 10.Methods: Two groups of pigs were exposed to mechanical ventilation for 24 hours before bacterial inoculation and six h of experimental pneumonia (total experimental time 30 h): A(30h+Etx) (n = 6, endotoxin 0.063 mu g x kg(-1) x h(-1)) and B-30h (n = 6, saline). A third group, C-6h (n = 8), started the experiment at the bacterial inoculation unexposed to endotoxin or mechanical ventilation (total experimental time 6 h). Bacterial inoculation was performed by tracheal instillation of 1x10(11) colony-forming units of P. aeruginosa. Bacterial cultures and wet-to-dry weight ratio analyses were done on lung tissue samples postmortem. Separate group comparisons were done between A(30h+Etx) vs.B-30h (Inflammation) and B-30h vs. C-6h (Ventilation Time) during the bacterial phase of 6 h.Results: P. aeruginosa growth was highest in A(30h+Etx), and lowest in C-6h (Inflammation and Ventilation Time both p<0.05). Lung wet-to-dry weight ratios were highest in A(30h+Etx) and lowest in B-30h (Inflammation p<0.01, Ventilation Time p<0.05). C-6h had the highest TNF-alpha levels in plasma (Ventilation Time p<0.01). No differences in bronchoalveolar lavage variables between the groups were observed.Conclusions: Mechanical ventilation and systemic inflammation before the onset of pneumonia increase the growth of P. aeruginosa in lung tissue. The attenuated growth of P. aeruginosa in the non-pre-exposed animals (C-6h) was associated with a higher systemic TNF-alpha production elicited from the bacterial challenge.
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