Traumatic and septic shock alias post-trauma critical illness

Association between trauma exposure and respiratory disease-A Mendelian randomization study

BACKGROUND

Trauma is a well-known risk factor for many disease, but the effect of trauma on respiratory disease is unclarified. In the present study, we aimed to evaluate the association between trauma and respiratory disease.

METHOD

Using both United Kingdom biobank and Finnish biobank genome-wide association study data (GWAS), we performed a two-sample Mendelian randomization (MR) analysis to evaluate the relationship between trauma and respiratory disease. We used four methods including inverse-variance weighted (IVW), weighted median, Maximum likelihood, and MR-Egger in this MR analysis. The IVW MR was selected as the main method. We also performed multivariable Mendelian randomization (MVMR) to simultaneously assess the independent impact of trauma exposure on respiratory disease.

RESULTS

In the main two-sample MR analysis, trauma exposure was significantly associated with increased risk of respiratory disease (OR 1.15, 95%CI: 1.05-1.25). Besides, there was no heterogeneity and horizontal pleiotropy observed in the sensitivity analysis. After adjusting for pack years of smoking and body mass index (BMI), trauma exposure retained its association with respiratory disease (OR, 1.13, 95%CI, 1.04-1.23 adjusted by pack years of smoking; and OR, 1.11, 95%CI, 1.04-1.18 adjusted by BMI).

CONCLUSION

Our study discovered the association between trauma exposure and the increased risk of respiratory disease, suggesting the prevention and treatment with trauma to reduce the risk of respiratory disease.

The Flatness Index of Inferior Vena Cava can be an Accurate Predictor for Hypovolemia in Multi-Trauma Patients

INTRODUCTION

Shock is the leading cause of death in multi-trauma patients and must be detected at an early stage to improve prognosis. Many parameters are used to predict clinical condition and outcome in trauma. Computed tomography (CT) signs of hypovolemic shock in trauma patients are not clear yet, requiring further research. The flatness index of inferior vena cava (IVC) is a helpful method for this purpose.

METHODS

This is a prospective, cross-sectional study which included adult multi-trauma patients (>18 years) who were admitted to the emergency department (ED) and underwent a thoraco-abdominal CT from 2017 through 2018. The main objective of this study was to investigate whether the flatness index of IVC can be used to determine the hypovolemic shock at an early stage in multi-trauma patients, and to establish its relations with shock parameters. The patients' demographic features, trauma mechanisms, vitals, laboratory values, shock parameters, and clinical outcome within 24 hours of admission were recorded.

RESULTS

Total of 327 (229 males with an average age of 40.9 [SD = 7.93]) patients were included in the study. There was no significant difference in the flatness index of IVC within genders (P = .134) and trauma mechanisms (P = .701); however, the flatness index of IVC was significantly higher in hypotensive (systolic blood pressure [SBP] ≤90 mmHg and/or diastolic blood pressure [DBP] ≤60 mmHg; P = .015 and P = .019), tachycardic (P = .049), and hypoxic (SpO2 ≤%94; P <.001) patients. The flatness index of IVC was also higher in patients with lactate ≥ 2mmol/l (P = .043) and patients with Class III hemorrhage (P = .003). A positive correlation was determined between lactate level and the flatness index of IVC; a negative correlation was found between Glasgow Coma Scale (GCS) and Revised Trauma Score (RTS) with the flatness index of IVC (for each of them, P <.05).

CONCLUSION

The flatness index of IVC may be a useful method to determine the hypovolemic shock at an early stage in multi-trauma patients.

Dual roles of commensal bacteria after intestinal ischemia and reperfusion

PURPOSE

The roles of commensal bacteria after intestinal ischemia and reperfusion (IIR) are unclear. In current study, we aim to investigate the effects and underlying mechanisms of commensal bacteria in injury and epithelial restitution after IIR.

METHODS

Commensal gut bacteria were deleted by broad-spectrum antibiotics in mice. IIR was induced by clamping superior mesenteric artery. Intestinal injury, permeability, epithelial proliferation, and proinflammatory activity of mesenteric lymph were investigated.

RESULTS

Commensals deletion improved mice survival in the early phase, but failed to improve the overall survival at 96 h after IIR. Commensals deletion reduced proliferation of intestinal epithelial cells (IEC) and augmented proinflammatory activity of mesenteric lymph after IIR. Lipopolysaccharides (LPS) supplement promoted IEC proliferation and improved survival in mice with commensals deletion after IIR. LPS induced production of prostaglandin E2 (PGE2) in mucosa via toll-like receptor 4-NFκB-cyclooxygenase 2 pathway. PGE2 enhanced IEC proliferation in vivo, which was preceded by activation of Akt and extracellular signal-regulated kinase (ERK) 1/2. Blocking of EGFR, PI3K/Akt activity abolished LPS-induced IEC proliferation.

CONCLUSIONS

Commensal bacteria are essential for epithelial restitution after IIR, which enhance IEC proliferation via induction of PGE2.

New evaluation therapies for sepsis

This article presents an analysis of the literature of the last 2 years on the treatment of sepsis and septic shock. It appears that most of the antimediator therapies applied in phase II or III clinical trials yielded disappointing results. But, many other therapeutic approaches are proposed or are ongoing, and many papers report critical analysis of the reasons for the lack of success of past clinical trials.

A Brief Overview of Acute Respiratory Distress Syndrome

BACKGROUND

The low pO: (2) in traumatic and septic shock was first documented at Walter Reed Army Medical Center starting in 1960. It was postulated that this respiratory failure was due to the occlusion of the pulmonary microcirculation by the microclots of disseminated intravascular coagulation (DIC).

MATERIALS AND METHODS

Animal studies showed that pulmonary failure and death could be caused by intravenous injection of a killed culture of either Escherichia coli or pneumococcal organisms or by severe muscle contusion. Severe clinical septic and traumatic shock cases were studied.

RESULTS

Injection of either killed E. coli or killed pneumococci resulted in acute respiratory distress syndrome (ARDS) and death in pigs. Muscle contusion also resulted in ARDS and death in pigs. Both ARDS and death were prevented by administration of a plasminogen activator, and ARDS in human septic or traumatic shock were safely and effectively treated by administration of a plasminogen activator.

CONCLUSIONS

Acute respiratory distress syndrome can be caused by DIC, which blocks the microcirculation of any and all organs. These microclots can be safely lysed by a plasminogen activator, thus treating ARDS and saving lives.

The distinct and secondary harmful effect of pelvic and extremity injury on the outcome of laparotomy for trauma

HYPOTHESIS

Extra-abdominal injury negatively affects the outcome of abdominal injury following trauma laparotomy.

DESIGN

Retrospective review of 920 consecutive patients receiving laparotomy for trauma who survived more than 24 h between January 1989 and May 1998 at a Level 1 trauma center. Major abdominal complications (MAC) were defined as: abdominal compartment syndrome (ACS), abscess/peritonitis, enterocutaneous fistula, necrotizing fasciitis, and necrotizing pancreatitis.

METHODS

Univariant and multivariant logistic regression were used to identify predictors of MAC.

RESULTS

Sixty-nine patients (7.5%) developed one or more MAC. Patients who developed MAC had higher injury severity scores (ISS), abdominal trauma indices (ATI), and blood transfusions in the first 24 h (PRCs) than patients who did not develop MAC. Patients with MAC were more likely to have suffered a thoracic or pelvic injury with an abbreviated injury scale (AIS) > or =3 and were more likely to have received an extremity injury (AIS > or =3) operation than patients without MAC. Independent predictors of MAC in multivariant analysis included colon injury (AIS > or =3) [odds ratio (OR) = 3.1, 95% confidence interval (CI) 1.5- 6.3)], pelvic injury (AIS > or =3) or operation for extremity injury (AIS > or =3) [OR 2.9, 95% CI 1.5-5.3], and ATI (OR = 1.03 for each 10 unit increase in ATI, 95% CI 1.02-1.05). PRCs did not independently predict MAC.

CONCLUSION

The outcome of laparotomy for trauma (both blunt and penetrating) is negatively affected by a severe pelvic injury or a severe extremity injury operation independent of initial hemorrhage and abdominal injury severity.

The role of microvascular thrombosis in sepsis

The acute inflammatory response to sepsis gives rise to significant morbidity and mortality. The mechanisms underlying this form of tissue injury are poorly understood. This review examines the evidence that tissue ischaemia due, to generalized microvascular thrombosis may play an important role. Microvascular thrombosis is probably an adaptive response that prevents bacteria in the tissues reaching the systemic circulation via the capillaries. In time, a definitive response by leucocytes removes the bacteria and repairs the damaged tissues. There is however evidence that if microvascular thrombosis becomes generalized, then extensive tissue ischaemia may precipitate organ failure and death. Post-mortem studies of patients with sepsis demonstrate microvascular thrombi in many organs including the kidney, liver, lung, gut, adrenals and brain, and the degree of organ injury is related to the quantity of thrombi. Furthermore studies in human and animal models of sepsis demonstrate therapies that inhibit coagulation or promote fibrinolysis reduce organ failure and mortality. In view of the personal and economic burdens that tissue injury associated with the acute inflammatory response places on the community, further studies to establish the role of microvascular thrombosis are clearly required. Such studies may lead to new therapies to limit or prevent this form of injury.

Effects of mechanical ventilation on platelet microparticles in bronchoalveolar lavage fluid

INTRODUCTION

Mechanical ventilation (MV) is considered to contribute to lung injury. Platelet membrane-derived microparticles (PMPs) are procoagulant and participate in the inflammatory process. The bronchoalveolar space could, besides plasma, be a site of origin of these microparticles. We evaluated the presence of these PMPs and two prostaglandin-derived metabolites in bronchoalveolar lavage fluid (BALF) regarding their possible relation to MV.

MATERIALS AND METHODS

Before and after 1 h of MV, PMPs and prostaglandin metabolites were analyzed, in BALF from 14 anesthetized pigs, by flow cytometry and RIA, respectively. Tracheal mucus from five humans was analyzed for PMPs at extubation after surgery.

RESULTS

Activated PMPs and prostaglandin metabolites were present in all BALF samples. The time needed to count 5000 cellular events was prolonged six-fold after 1 h of mechanical ventilation (p<0.001). The relative content of PMPs was constant in all samples. The PMPs were thrombogenic, i.e. they were fibrinogen, p-selectin and von Willebrand factor positive. Lavage did not per se affect the period necessary to count 5000 cellular events. PMPs in human tracheal mucus were in the same range as in the pig after 1 h of MV aiming at a PaCO(2) between 5.0 and 5.5 kPa.

CONCLUSIONS

Activated PMPs are present in the pulmonary air-liquid interface. The prolongation of the time needed to count 5000 cellular events in BALF after MV indicates activation and adherence. Adherent microparticles bind neutrophils, which may aggravate pathological processes leading to pulmonary dysfunction. Evaluation of PMPs in BALF may be useful in evaluating strategies for lung-protective ventilator treatment.

A shock toxin that produces disseminated intravascular coagulation and multiple organ failure

OBJECTIVE

To introduce a new concept in the etiology and treatment of traumatic and septic shock. It describes 3 types of shock: (1) hypovolemic shock, (2) traumatic shock, and (3) septic shock.

BACKGROUND

The mortality of septic shock in both total number and mortality rate has been increasing over the past 40 years despite major advances in diagnosis and treatment, including a number of "magic bullets." Trauma is the No. 1 cause of death in persons under the age of 44 and the No. 3 cause of all deaths. Traumatic shock has been assumed to be caused by hypovolemia; however, many traumatic shock patients die with a normal blood volume, usually after several days. Septic shock in pigs using an injection of killed Escherichia coli organisms produced disseminated intravascular coagulation (DIC). Control pigs treated with plasminogen activator survived. Septic shock in humans also treated with plasminogen activator showed excellent results. Traumatic shock studied in pigs showed excellent results with plasminogen activator. A normal blood volume was maintained with the use of intravenous fluids. Traumatic shock in humans also treated by plasminogen activator showed excellent results. The improvement in PaO2 and other parameters demonstrated in these studies provides a new possibility in the treatment of trauma and/or sepsis induced acute respiratory distress syndrome (ARDS). DIC is almost always present in traumatic and septic shock and probably in the course of ARDS and multiple organ failure. The DIC is probably initiated by tissue cell or bacterial cell destruction, which liberates a thrombogenic aminophospholipid that forms the inner layer of all cell walls.

Treatment of Severe Acute Respiratory Distress Syndrome: A Final Report on a Phase I Study

Adult respiratory distress syndrome (ARDS) has a high mortality. Its only effective treatment is respiratory therapy. If this fails mortality is probably 100 per cent. No other treatment for ARDS has proved effective including “magic bullets.” Twenty patients suffering from ARDS secondary to trauma and/or sepsis failed to respond to treatment with mechanical ventilation and positive end-expiratory pressure. On the assumption that disseminated intravascular coagulation initiates ARDS by occluding the pulmonary microcirculation with microclots, the patients were treated with plasminogen activators. The patients responded with significant improvement in partial pressure of oxygen in arterial blood. No bleeding occurred and clotting parameters remained normal. We conclude that ARDS can be safely treated with plasminogen activator.

Microcirculatory dysfunction in sepsis: a pathogenetic basis for therapy?

Sepsis is a frequent complication of multiple organ dysfunction syndrome and remains a major problem of intensive care medicine. It is also a common factor in the final cause of death in hospital populations. Clinical observations, assisted by invasive monitoring techniques as well as pathological-anatomical studies, clearly indicate that microcirculatory dysfunction lies at the centre of sepsis pathogenesis. Numerous animal models, from rodents to primates, many of which employ bacteria or their toxins, especially endotoxins, have helped to shed light on the pathomechanisms leading to this dysregulation in the peripheral circulation. Among these are activation of humoral and cellular inflammatory mediator systems, with special emphasis on neutrophil-endothelial interactions, affecting endothelial barrier function and vasoregulation and ultimately leading to severely perturbed oxygen transport and utilization. In vitro studies have provided more insight into the molecular mechanisms involved in this microcirculatory dysfunction, although much more attention must be directed towards microvascular endothelial cells and the role of heterogeneity of response in various vascular beds. These experimental data must in turn be validated by comparing with the human in situ situation, both clinical and morphological. This review aims at a critical appraisal of the clinical and experimental evidence for sepsis-induced dysregulation of the microcirculation and how knowledge of the underlying cellular and molecular pathology could be used to make therapy more rational and effective. To date, therapeutic approaches, such as anti-cytokine and anti-oxidant regimens, which have been highly successful in experimental models, have failed to demonstrate clinical efficacy. Newer approaches, such as targeting the coagulation system, nitric oxide synthesis or intracellular signal transduction, are also discussed. The necessity to focus on the role of anti-inflammatory mediators, as well as the pathogenetic significance of important molecular groups, such as the heat shock proteins, which until now have been given scant attention, will be stressed.