Diagnosis of infection in sepsis: An evidence-based review

Management of peritonitis in the critically ill patient

Severe secondary peritonitis carries significant mortality, despite advancements in critical care support and other therapies. Surgical management requires a multidisciplinary approach to guide the timing and the number of interventions necessary to eradicate the septic foci and create optimal healing with the fewest complications. Research is needed regarding the best surgical strategy for very severe cases. The use of deferred primary anastomosis seems safe in patients presenting with hemodynamic instability and hypoperfusion. These patients have a high risk of anastomotic failure and fistula formation. Allowing for aggressive resuscitation and judicious assessment of the progression of local inflammation are safe strategies to achieve the highest success and minimize serious and protracted complications in patients who survive the initial septic insult.

[Managing lower respiratory tract infections in immunocompetent patients. Definitions, epidemiology, and diagnostic features]

Les infections respiratoires basses sont une des principales cause de mortalité dans le monde et les pneumopathies représentent en France la première cause de décès d'origine infectieuse. Trois entités nosologiques distinctes sont habituellement isolées en fonction de la localisation infectieuse : la bronchite aiguë, la pneumopathie et la bronchopneumopathie (atteignant les bronches et le parenchyme pulmonaire). En cas d'infections de l'arbre bronchique dans le cadre d'une bronchopathie chronique on parle de décompensation infectieuse de la maladie bronchique. Les deux principales difficultés diagnostiques de ces infections sont de déterminer la présence d'une participation alvéolaire au processus infectieux et de définir l'agent (ou les agents) pathogènes. Ces deux éléments vont conditionner la prise en charge thérapeutique. En dehors de l'examen physique, indispensable dans ce contexte, seule la radiographie thoracique pourra, en cas de persistance d'un doute, permettre de confirmer la présence d'une participation alvéolaire. Le diagnostic microbiologique pose la question de sa nécessité systématique et celui de sa valeur. Il n'est pas indispensable de réaliser un diagnostic microbiologique de certitude dans tous les cas. La décision de documentation doit répondre à deux impératifs : faisabilité et valeur diagnostique. La valeur d'un prélèvement dépend de son aptitude à mettre en évidence l'agent pathogène et dans certains cas de la possibilité d'en déterminer le profil de sensibilité (qui reste une indication majeure à la réalisation de ces prélèvements).

The role of bundles in sepsis care

The understanding of the pathogenesis of sepsis has substantially changed in past years and continues to improve. New therapeutic options are being developed and incorporated into clinical practice. There are different specific interventions and therapies that benefit patients' outcome. As demonstrated by the early goal-directed therapy strategy, the success of the resuscitation treatment is strongly time dependent. The recognition of severe sepsis should be accompanied without delay by very well defined therapeutic measures. In 2002 the Surviving Sepsis Campaign was introduced with the overall goal of increasing clinicians' awareness and improving outcome in severe sepsis and septic shock.

Diagnosis and treatment of catheter-related infections in paediatric oncology: an update

Otherwise unexplained clinical signs of infection in patients with long-term tunnelled or totally implanted central venous access devices (CVADs) are suspected to be CVAD-associated. Diagnostic methods include catheter swabs, blood cultures and cultures of the catheter tip or port reservoir. In the case of a suspected CVAD-related bloodstream infection in paediatric oncology patients, in-situ treatment without prompt removal of the device can be attempted. Removal of the CVAD should be considered if bacteraemia persists or relapses > or = 72 h after the initiation of (in-vitro effective) antibacterial therapy administered through the line. Timely removal of the device is also recommended if the patient suffers from a complicated infection, or if Staphylococcus aureus, Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii or Candida spp. are isolated from blood cultures. Duration of therapy depends on the immunological recovery of the patient, the pathogen isolated and the presence of related complications, such as thrombosis, pneumonia, endocarditis and osteomyelitis. Antibiotic lock techniques in addition to systemic treatment are beneficial for Gram-positive infections. Although prospectively controlled studies are lacking, the concomitant use of urokinase locks and taurolidine secondary prophylaxis seem to favour catheter salvage.

Vascular Catheter-Related Infection and Sepsis

BACKGROUND

Catheter-related sepsis is a clinical syndrome characterized by the presence of a catheter-associated infection along with a systemic inflammatory response. The continual increase in the use of central venous catheters (CVCs) has been associated with a substantial risk of infectious complications that prolong the hospital stay and increase costs.

METHODS

The literature on CVCs was reviewed to determine the incidence of catheterrelated sepsis, its diagnosis, and the role of biofilms in pathogenesis.

RESULTS

The European Sepsis Group recently reported that 28% of CVC infections in intensive care unit patients were associated with sepsis, 24% with severe sepsis, and 30% with septic shock. Clinical diagnosis remains difficult. After CVC insertion, the intravascular portion of the device is covered rapidly by a thrombin layer, rich in host-derived proteins, that forms a conditioning film and promotes surface adherence of microbial colonizers. These microorganisms then enter their sessile mode of growth, secreting an exopolysaccharide slime within which organism density is regulated by quorum-sensing molecules. Microorganisms are dispersed in clumps that can become septic emboli. Antiadhesive, antiseptic, and antibiotic coatings of catheters have demonstrated only modest clinical efficacy.

CONCLUSION

Our group is involved in the design and in vitro assessment of new polymeric matrices for controlled release of antimicrobial molecules, and in comparative clinical studies of conventional versus antibiotic-coated or -impregnated catheters.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

[Epidemiology of severe sepsis]

Internationally recognized definitions of septic syndromes are available and make it possible to conduct more homogenous clinical trials. Nearly 15% of patients in intensive care have severe sepsis, and two thirds of them septic shock. In France, it is estimated that approximately 75,000 patients with severe sepsis are admitted to intensive care units, and the frequency of sepsis is increasing. Hospital mortality is 20% for simple sepsis and 40% and higher for cases of severe sepsis or septic shock; it has nonetheless been improving over the past decade. Prognosis depends on the severity of organ dysfunctions, in particular, of cardiovascular failure. Early identification of sepsis and of patients at risk of developing septic shock, together with rapid intervention aiming especially to correct hemodynamic disorders, is likely to improve prognosis.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Severe Sepsis and Septic Shock in Adult Patients: An Approach to Management and Future Trends

Severe sepsis is sepsis associated with acute organ dysfunction. Septic shock in turn, implies severe sepsis that has led to circulatory shock refractory to fluid resuscitation alone. The immediate approach to severe sepsis follows the ABCs of resuscitation: Airway, Breathing, and Circulation. Special emphasis on the circulation involves early goal-directed therapy, adequate fluid resuscitation, and vasopressor/inotropic support. Once the patient's cardiorespiratory status is stabilized, efforts must be directed at uncovering the source and empirically yet accurately treating the infective underpinnings of severe sepsis. Following that, each of the patient's other organ systems at risk needs to be addressed: Renal/metabolic, gastrointestinal, hematological, and endocrine. Novel treatments will target both the proinflammatory and procoagulation cascades of sepsis.

[The diagnosis of sepsis]

The early diagnosis of sepsis is mandatory for the further reduction of mortality due to sepsis. Current findings exist that accentuate the role of the time factor, comparable with acute myocardial infarction or with ischemic stroke. On the other hand, there are no generally accepted diagnostics for sepsis, realizing the demands of early diagnosis and based on the physician's experience.The diagnostics start with the recognition of the inflammatory reaction caused by infection (at least 2 of 4 criteria of inflammatory reaction have to be fulfilled). This definition has high sensitivity, but remarkably lower specificity and it leads either to too frequent admissions or only to hospitalization in case of a complicating organ failure. Making a careful history and knowledge about sepsis are essential for the out-patient department physicians. In addition to the varying pictures of sepsis, the clinicians have laboratory findings available, most of all procalcitonin. Patients have to be considered as septic with a serum PCT level higher than 1 ng/ml particularly when clinical signs do not exclude sepsis and in cases of positive blood cultures. Initially PCT is a product of macrophages if the defense reaction starts, but it becomes an infection marker, when the serum PCT level declines less than the half life falls.

Die Diagnose der Sepsis

Die frühe Diagnostik der Sepsis ist das Nadelöhr für die weitere Senkung der Sepsissterblichkeit. Inzwischen liegen Befunde vor, dass, vergleichbar mit akutem Myokardinfarkt und Schlaganfall, dem Faktor Zeit eine wichtige Rolle zukommt. Demgegenüber gibt es keine allgemein akzeptierte Sepsisdiagnostik, die der Forderung nach früher Diagnose und der Unabhängigkeit vom Erfahrungsstand des jeweiligen Arztes Rechnung tragen könnte.

Sepsis: Still Going Strong

Sepsis definitions help to understand and to better define a group of syndromes secondary to an infectious insult. The hierarchical continuum of inflammatory response leads, in absence of counterregulatory forces, to organ damage and death. We have learned first the response to treatment and afterwards the pathophysiology behind it. This lesson has, of course, not always been followed by a reduction of mortality. The definition, natural history, risk factors, diagnoses, and treatment based on emerging evidence will help to improve patient outcomes and mortality. Standardized care seems to improve survival, and validation and further evaluation of this care is necessary to maximize resources and outcomes.

Effect of ventilator-associated tracheobronchitis on outcome in patients without chronic respiratory failure: a case-control study

Introduction

Our objective was to determine the effect of ventilator-associated tracheobronchitis (VAT) on outcome in patients without chronic respiratory failure.

Methods

This was a retrospective observational matched study, conducted in a 30-bed intensive care unit (ICU). All immunocompetent, nontrauma, ventilated patients without chronic respiratory failure admitted over a 6.5-year period were included. Data were collected prospectively. Patients with nosocomial pneumonia, either before or after VAT, were excluded. Only first episodes of VAT occurring more than 48 hours after initiation of mechanical ventilation were studied. Six criteria were used to match cases with controls, including duration of mechanical ventilation before VAT. Cases were compared with controls using McNemar's test and Wilcoxon signed-rank test for qualitative and quantitative variables, respectively. Variables associated with a duration of mechanical ventilation longer than median were identified using univariate and multivariate analyses.

Results

Using the six criteria, it was possible to match 55 (87%) of the VAT patients (cases) with non-VAT patients (controls). Pseudomonas aeruginosa was the most frequently isolated bacteria (34%). Although mortality rates were similar between cases and controls (29% versus 36%; P = 0.29), the median duration of mechanical ventilation (17 days [range 3–95 days] versus 8 [3–61 days]; P < 0.001) and ICU stay (24 days [range 5–95 days] versus 12 [4–74] days; P < 0.001) were longer in cases than in controls. Renal failure (odds ratio [OR] = 4.9, 95% confidence interval [CI] = 1.6–14.6; P = 0.004), tracheostomy (OR = 4, 95% CI = 1.1–14.5; P = 0.032), and VAT (OR = 3.5, 95% CI = 1.5–8.3; P = 0.004) were independently associated with duration of mechanical ventilation longer than median.

Conclusion

VAT is associated with longer durations of mechanical ventilation and ICU stay in patients not suffering from chronic respiratory failure.