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Systemic Effects Induced by Hyperoxia in a Preclinical Model of Intra-abdominal Sepsis.

ABSTRACT: Supplemental oxygen is a supportive treatment in patients with sepsis to balance tissue oxygen delivery and demand in the tissues. However, hyperoxia may induce some pathological effects. We sought to assess organ damage associated with hyperoxia and its correlation with the production of reactive oxygen species (ROS) in a preclinical model of intra-abdominal sepsis. For this purpose, sepsis was induced in male, Sprague-Dawley rats by cecal ligation and puncture (CLP). We randomly assigned experimental animals to three groups: control (healthy animals), septic (CLP), and sham-septic (surgical intervention without CLP). At 18?h after CLP, septic (n = 39), sham-septic (n = 16), and healthy (n = 24) animals were placed within a sealed Plexiglas cage and randomly distributed into four groups for continuous treatment with 21%, 40%, 60%, or 100% oxygen for 24?h. At the end of the experimental period, we evaluated serum levels of cytokines, organ damage biomarkers, histological examination of brain and lung tissue, and ROS production in each surviving animal. We found that high oxygen concentrations increased IL-6 and biomarkers of organ damage levels in septic animals, although no relevant histopathological lung or brain damage was observed. Healthy rats had an increase in IL-6 and aspartate aminotransferase at high oxygen concentration. IL-6 levels, but not ROS levels, are correlated with markers of organ damage. In our study, the use of high oxygen concentrations in a clinically relevant model of intra-abdominal sepsis was associated with enhanced inflammation and organ damage. These findings were unrelated to ROS release into circulation. Hyperoxia could exacerbate sepsis-induced inflammation, and it could be by itself detrimental. Our study highlights the need of developing safer thresholds for oxygen therapy.

SUBMITTER: Garcia-Laorden MI

PROVIDER: S-EPMC7585649 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Systemic Effects Induced by Hyperoxia in a Preclinical Model of Intra-abdominal Sepsis.

García-Laorden M Isabel MI Rodríguez-González Raquel R Martín-Barrasa José L JL García-Hernández Sonia S Ramos-Nuez Ángela Á González-García H Celeste HC González-Martín Jesús M JM Kacmarek Robert M RM Villar Jesús J

Mediators of inflammation 20201015

Supplemental oxygen is a supportive treatment in patients with sepsis to balance tissue oxygen delivery and demand in the tissues. However, hyperoxia may induce some pathological effects. We sought to assess organ damage associated with hyperoxia and its correlation with the production of reactive oxygen species (ROS) in a preclinical model of intra-abdominal sepsis. For this purpose, sepsis was induced in male, Sprague-Dawley rats by cecal ligation and puncture (CLP). We randomly assigned exper ...[more]

PMID: 33122967

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Project description:BackgroundSevere complicated intra-abdominal sepsis (SCIAS) has high mortality, thought due in part to progressive bio-mediator generation, systemic inflammation, and multiple organ failure. Treatment includes early antibiotics and operative source control. At surgery, open abdomen management with negative-peritoneal-pressure therapy (NPPT) has been hypothesized to mitigate MOF and death, although clinical equipoise for this operative approach exists. The Closed or Open after Laparotomy (COOL) study (https://clinicaltrials.gov/ct2/show/NCT03163095) will prospectively randomize eligible patients intra-operatively to formal abdominal closure or OA with NPTT. We review the ethical basis for conducting research in SCIAS.Main bodyResearch in critically ill incapacitated patients is important to advance care. Conducting research among SCIAS is complicated due to the severity of illness including delirium, need for emergent interventions, diagnostic criteria confirmed only at laparotomy, and obtundation from anaesthesia. In other circumstances involving critically ill patients, clinical experts have worked closely with ethicists to apply principles that balance the rights of patients whilst simultaneously permitting inclusion in research. In Canada, the Tri-Council Policy Statement-2 (TCPS-2) describes six criteria that permit study enrollment and randomization in such situations: (a) serious threat to the prospective participant requires immediate intervention; (b) either no standard efficacious care exists or the research offers realistic possibility of direct benefit; (c) risks are not greater than that involved in standard care or are clearly justified by prospect for direct benefits; (d) prospective participant is unconscious or lacks capacity to understand the complexities of the research; (e) third-party authorization cannot be secured in sufficient time; and (f) no relevant prior directives are known to exist that preclude participation. TCPS-2 criteria are in principle not dissimilar to other (inter)national criteria. The COOL study will use waiver of consent to initiate enrollment and randomization, followed by surrogate or proxy consent, and finally delayed informed consent in subjects that survive and regain capacity.ConclusionsA delayed consent mechanism is a practical and ethical solution to challenges in research in SCIAS. The ultimate goal of consent is to balance respect for patient participants and to permit participation in new trials with a reasonable opportunity for improved outcome and minimal risk of harm.

Project description:IntroductionIntra-abdominal hypertension (IAH) causes atelectasis, reduces lung volumes and increases respiratory system elastance. Positive end-expiratory pressure (PEEP) in the setting of IAH and healthy lungs improves lung volumes but not oxygenation. However, critically ill patients with IAH often suffer from acute lung injury (ALI). This study, therefore, examined the respiratory and cardiac effects of positive end-expiratory pressure in an animal model of IAH, with sick lungs.MethodsNine pigs were anesthetized and ventilated (48 +/- 6 kg). Lung injury was induced with oleic acid. Three levels of intra-abdominal pressure (baseline, 18, and 22 mmHg) were randomly generated. At each level of intra-abdominal pressure, three levels of PEEP were randomly applied: baseline (5 cmH2O), moderate (0.5 × intra-abdominal pressure), and high (1.0 × intra-abdominal pressure). We measured end-expiratory lung volumes, arterial oxygen levels, respiratory mechanics, and cardiac output 10 minutes after each new IAP and PEEP setting.ResultsAt baseline PEEP, IAH (22 mmHg) decreased oxygen levels (-55%, P <0.001) and end-expiratory lung volumes (-45%, P = 0.007). At IAP of 22 mmHg, moderate and high PEEP increased oxygen levels (+60%, P = 0.04 and +162%, P <0.001) and end-expiratory lung volume (+44%, P = 0.02 and +279%, P <0.001) and high PEEP reduced cardiac output (-30%, P = 0.04). Shunt and dead-space fraction inversely correlated with oxygen levels and end-expiratory lung volumes. In the presence of IAH, lung, chest wall and respiratory system elastance increased. Subsequently, PEEP decreased respiratory system elastance by decreasing chest wall elastance.ConclusionsIn a porcine sick lung model of IAH, PEEP matched to intra-abdominal pressure led to increased lung volumes and oxygenation and decreased chest wall elastance shunt and dead-space fraction. High PEEP decreased cardiac output. The study shows that lung injury influences the effects of IAH and PEEP on oxygenation and respiratory mechanics. Our findings support the application of PEEP in the setting of acute lung injury and IAH.

Project description:BackgroundThe prognostic role of what a surgeon observes in the abdomen of patients with complicated intra-abdominal infection (cIAI) is largely unknown. The aim of this prospective study was to systemically analyze components of the intra-abdominal view (IAV) and their association to severe complicated intra-abdominal sepsis (SCIAS) or mortality.MethodsThe study cohort consisted of adult patients with cIAI. The operating surgeon filled a paper form describing the intra-abdominal view. Demographics, operative details, and preoperative physiological status were collected. Descriptive, univariate, and multivariate statistical analyses were performed, and a new score was developed based on regression coefficients. The primary outcome was a composite outcome of SCIAS or 30-day mortality, in which SCIAS was defined as organ dysfunctions requiring intensive care unit admission.ResultsA total of 283 patients were analyzed. The primary outcome was encountered in 71 (25%) patients. In the IAV, independent risk factors for the primary outcome were fecal or bile as exudate (odds ratio (OR) 1.98, 95% confidence interval 1.05-3.73), diffuse peritonitis (OR 2.15, 1.02-4.55), diffuse substantial redness of the peritoneum (OR 5.73, 2.12-15.44), and a non-appendiceal source of cIAI (OR 11.20, 4.11-30.54). Based on these factors, an IAV score was developed and its performance analyzed. The area under the receiver operating characteristic for the IAV score was 0.81. The IAV score also correlated significantly with several outcomes and organ dysfunctions.ConclusionsThe extent of peritonitis, diffuse substantial redness of the peritoneum, type of exudate, and source of infection associate independently with SCIAS or mortality. A high IAV score associates with mortality and organ dysfunctions, yet it needs further external validation. Combining components of IAV into comprehensive scoring systems for cIAI patients may provide additional value compared to the current scoring systems.Trial registrationThe study protocol was retrospectively registered on April 4, 2016, right after the first enrolled patient at Clinicaltrials.gov database (NCT02726932).

Project description:Desmoid fibromatosis is a rare but locally aggressive tumor comprised of myofibroblasts. Desmoids do not have the ability to metastasize but can cause significant morbidity and mortality by local invasion. These tumors may occur throughout the body, but are commonly found on the abdominal wall and within the intestinal mesentery. Desmoids in these areas may cause unique clinical problems for physicians and patients. Mutations in either the β-catenin or the APC genes are usually the cause for the development of these tumors with the former comprising the sporadic development of tumors and the latter being associated with familial adenomatous polyposis syndrome. Surgical resection with histologically negative margins has been the cornerstone of therapy for this disease, but this paradigm has begun to shift. It is now common to accept a microscopically positive margin after resection as recurrence rates may not be significantly affected. An even more radical evolution in management has been the recent movement towards "watchful waiting" when new desmoids are diagnosed. As the natural history of desmoids has become better understood, it is evident that some tumors will not grow and may even spontaneously regress sparing patients the morbidity of more aggressive therapy. Other modalities of treatment for desmoids include radiation and systemic therapy which both can be used adjuvantly or as definitive therapy and have shown durable response rates as single therapy regimens. The decision to use radiation and/or systemic therapies is often based on tumor biology, tumor location, surgical morbidity, and patient preference. Systemic therapy options have increased to include hormonal therapies, non-steroidal anti-inflammatory drugs and chemotherapy, as well as targeted therapies. Unfortunately, the rarity of this disease has resulted in a scarcity of randomized trials to evaluate any of these therapies emphasizing the need for this disease to be treated at high volume multidisciplinary institutions.

Dataset Information

Systemic Effects Induced by Hyperoxia in a Preclinical Model of Intra-abdominal Sepsis.

Publications

Systemic Effects Induced by Hyperoxia in a Preclinical Model of Intra-abdominal Sepsis.

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