Sepsis-induced mitochondrial dysfunction : a narrative review

Sepsis represents a deranged and exaggerated systemic inflammatory response to infection and is associated with vascular and metabolic abnormalities that trigger systemic organic dysfunction. Mitochondrial function has been shown to be severely impaired during the early phase of critical illness, with a reduction in biogenesis, increased generation of reactive oxygen species and a decrease in adenosine triphosphate synthesis of up to 50%. Mitochondrial dysfunction can be assessed using mitochondrial DNA concentration and respirometry assays, particularly in peripheral mononuclear cells. Isolation of monocytes and lymphocytes seems to be the most promising strategy for measuring mitochondrial activity in clinical settings because of the ease of collection, sample processing, and clinical relevance of the association between metabolic alterations and deficient immune responses in mononuclear cells. Studies have reported alterations in these variables in patients with sepsis compared with healthy controls and non-septic patients. However, few studies have explored the association between mitochondrial dysfunction in immune mononuclear cells and unfavorable clinical outcomes. An improvement in mitochondrial parameters in sepsis could theoretically serve as a biomarker of clinical recovery and response to oxygen and vasopressor therapies as well as reveal unexplored pathophysiological mechanistic targets. These features highlight the need for further studies on mitochondrial metabolism in immune cells as a feasible tool to evaluate patients in intensive care settings. The evaluation of mitochondrial metabolism is a promising tool for the evaluation and management of critically ill patients, especially those with sepsis. In this article, we explore the pathophysiological aspects, main methods of measurement, and the main studies in this field

Mortality of septic shock patients is associated with impaired mitochondrial oxidative coupling efficiency in lymphocytes : a prospective cohort study

Background: Septic shock is a life-threatening condition that challenges immune cells to reprogram their mitochondrial metabolism towards to increase ATP synthesis for building an appropriate immunity. This could print metabolic signatures in mitochondria whose association with disease progression and clinical outcomes remain elusive. Method: This is a single-center prospective cohort study performed in the ICU of one tertiary referral hospital in Brazil. Between November 2017 and July 2018, 90 consecutive patients, aged 18 years or older, admitted to the ICU with septic shock were enrolled. Seventy-five patients had Simplified Acute Physiology Score (SAPS 3) assessed at admission, and Sequential Organ Failure Assessment (SOFA) assessed on the first (D1) and third (D3) days after admission. Mitochondrial respiration linked to complexes I, II, V, and biochemical coupling efficiency (BCE) were assessed at D1 and D3 and Δ (D3–D1) in isolated lymphocytes. Clinical and mitochondrial endpoints were used to dichotomize the survival and death outcomes. Our primary outcome was 6-month mortality, and secondary outcomes were ICU and hospital ward mortality. Results: The mean SAPS 3 and SOFA scores at septic shock diagnosis were 75.8 (± 12.9) and 8 (± 3) points, respectively. The cumulative ICU, hospital ward, and 6-month mortality were 32 (45%), 43 (57%), and 50 (66%), respectively. At the ICU, non-surviving patients presented elevated arterial lactate (2.8 mmol/L, IQR, 2–4), C-reactive protein (220 mg/L, IQR, 119–284), and capillary refill time (5.5 s, IQR, 3–8). Respiratory rates linked to CII at D1 and D3, and ΔCII were decreased in non-surviving patients. Also, the BCE at D1 and D3 and the ΔBCE discriminated patients who would evolve to death in the ICU, hospital ward, and 6 months after admission. After adjusting for possible confounders, the ΔBCE value but not SOFA scores was independently associated with 6-month mortality (RR 0.38, CI 95% 0.18–0.78; P = 0.009). At a cut-off of − 0.002, ΔBCE displayed 100% sensitivity and 73% specificity for predicting 6-month mortality. Conclusions: The ΔBCE signature in lymphocytes provided an earlier recognition of septic shock patients in the ICU at risk of long-term deterioration of health status

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Thrombin activatable fibrinolysis inhibitor as a bleeding predictor in liver transplantation: a pilot observational study

Objective: To correlate the levels of thrombin activatable fibrinolysis inhibitor in the immediate postoperative period and at 24 hours postoperatively with the volume of intraoperative bleeding. Methods: Twenty-one patients allocated immediately before (elective or emergency) liver transplantation were analyzed. Blood samples were collected for thrombin activatable fibrinolysis inhibitor analysis at three different time points: immediately before liver transplantation (preoperative thrombin activatable fibrinolysis inhibitor), immediately after the surgical procedure (immediate postoperative thrombin activatable fibrinolysis inhibitor), and 24 hours after surgery (thrombin activatable fibrinolysis inhibitor 24 hours after surgery). The primary outcome of the study was to correlate the preoperative and immediate postoperative levels of thrombin activatable fibrinolysis inhibitor with intraoperative blood loss. Results: There was a correlation between the preoperative thrombin activatable fibrinolysis inhibitor levels and bleeding volume (ρ = -0.469; p = 0.05) but no correlation between the immediate postoperative thrombin activatable fibrinolysis inhibitor and bleeding volume (ρ = -0.062; p = 0.79)

Os diferentes delineamentos de pesquisa e suas particularidades na terapia intensiva

RESUMO Os diferentes delineamentos de pesquisa apresentam diversas vantagens e limitações, inerentes às suas características principais. O conhecimento sobre o emprego adequado de cada um deles é de grande importância na aplicabilidade da epidemiologia clínica. Em terapia intensiva, uma classificação hierárquica dos delineamentos, sem compreender suas peculiaridades neste contexto, pode muitas vezes ser errônea, devendo-se atentar para problemas corriqueiros em ensaios clínicos randomizados e em revisões sistemáticas/metanálises, que abordem questões clínicas referentes a cuidados de pacientes gravemente enfermos

Thrombin activatable fibrinolysis inhibitor como preditor de sangramento no transplante hepático: estudo piloto observacional

RESUMO Objetivo: Correlacionar os níveis de thrombin activatable fibrinolysis inhibitor no pós-operatório imediato e com 24 horas de pós-operatório com o volume de sangramento tansoperatório. Métodos: Foram analisados vinte e um pacientes alocados imediatamente antes do transplante hepático (eletivo ou de urgência), com coleta de amostras sanguíneas para análise de thrombin activatable fibrinolysis inhibitor em três diferentes momentos: imediatamente antes do transplante hepático (thrombin activatable fibrinolysis inhibitor pré-operatório), imediatamente após o procedimento cirúrgico (thrombin activatable fibrinolysis inhibitor pós-operatório imediato) e após 24 horas do final da cirurgia (thrombin activatable fibrinolysis inhibitor 24 horas pós-operatório). O principal desfecho do estudo foi correlacionar os níveis de thrombin activatable fibrinolysis inhibitor pré-operatório e de thrombin activatable fibrinolysis inhibitor pós-operatório imediato com perda sanguínea no transoperatório. Resultados: Houve correlação entre thrombin activatable fibrinolysis inhibitor pré-operatório e o volume de sangramento (ρ = -0,469; p = 0,05), mas não de thrombin activatable fibrinolysis inhibitor pós-operatório imediato (ρ = -0,062; p = 0,79). Em análise de regressão linear, nenhuma das variáveis incluídas (hemoglobina pré, fibrinogênio pré e thrombin activatable fibrinolysis inhibitor pré-operatório) se mostrou preditor de sangramento. Houve tendência semelhante na variação entre os níveis de thrombin activatable fibrinolysis inhibitor durante os três diferentes momentos e os níveis de fibrinogênio. Pacientes que evoluíram a óbito em até 6 meses (14,3%) apresentaram níveis diminuídos de thrombin activatable fibrinolysis inhibitor pré-operatório e de thrombin activatable fibrinolysis inhibitor pós-operatório imediato, comparando-se aos sobreviventes (pré-operatório: 1,3 ± 0,15 versus 2,55 ± 0,53; p = 0,06; e pós-operatório imediato: 1,2 ± 0,15 versus 2,5 ± 0,42; p = 0,007). Conclusão: Houve correlação moderada entre thrombin activatable fibrinolysis inhibitor pré-operatório e o sangramento transoperatório em transplante hepático, porém seu papel preditivo independente de outras variáveis ainda permaneceu incerto. Thrombin activatable fibrinolysis inhibitor pré-operatório e pós-operatório imediato podem ter um papel na avaliação da sobrevida dessa população, necessitando-se confirmar em novos estudos, de maior tamanho amostral