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Sepsis . Tara Benton, MD Pediatric Critical Care Fellow October 24, 2011. Objectives. Definitions Epidemiology Microbiology Pathophysiology Guidelines for treatment Prevention. Sepsis.
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Sepsis Tara Benton, MD Pediatric Critical Care Fellow October 24, 2011
Objectives • Definitions • Epidemiology • Microbiology • Pathophysiology • Guidelines for treatment • Prevention
Sepsis • “clinical syndrome that complicates severe infection and is characterized by systemic inflammation and widespread tissue injury”
Definitions • SIRS (systemic inflammatory response syndrome) • At least 2 of the 4 following criteria (abnormal temp or WBC must be one of them) • Temperature>38.5 or <36C • Tachycardia (>2 SD above normal for age in absence of external stimulus, chronic drugs or painful stimuli) • OR otherwise unexplained persistent elevation over a 0.5-4 hr period • OR for children <1 yr old: bradycardia, defined as a mean HR <10th % for age • Mean tachypnea>2 SD above normal for age or mechanical ventilation for an acute process • WBC elevated or depressed for age or >10% neutrophils International Consensus Conference on Pediatric Sepsis 2005
Definitions • Infection defined as a suspected or proven (by positive culture, tissue stain or PCR test) infection caused by any pathogen OR a clinical syndrome associated with a high probability of infection • Sepsis = SIRS + infection • Severe Sepsis = SEPSIS + CV dysfunction OR ARDS OR 2 other organ dysfunctions • Septic Shock = SEPSIS + CV dysfunction International Consensus Conference on Pediatric Sepsis 2005
Definitions • Shock • Inadequate perfusion and oxygenation of the body and its organs • Delivery of substrate ≠ demand
Epidemiology • Bacterial sepsis is the leading cause of medical admissions to the PICU • Worldwide, sepsis is the most common cause of death in infants • In 1995 Watson et al published a large population based study evaluating severe sepsis - 0.56 cases per 1000 children (total of 40,000 cases each year) • More common in infants especially low-birth-weight, least common in 10-14yr • Half of all patients in this study had underlying medical conditions • Respiratory infection and primary bacteremia encompasses >40% of all causes
Epidemiology • Mortality is consistent at ~10% across age groups • Severity of illness does correlate with mortality (in adults) • SIRS – 7% • Sepsis – 16% • Severe Sepsis – 20% • Septic Shock - 46%
Microbiology • Most common pathogen overall is Staphylococcus of all types • In the population study previously discussed, 18% of cases overall and 26% of neonatal infections • An international study from 2007, 44% of all cases were caused by Staph • Most common isolate overall is Staph aureus • Other organisms noted in above studies: Streptococcus and Pseudomonas aeruginosa • Viral sepsis may be indistinguishable from bacterial sepsis • HSV in neonates
Risk factors • Genetic • Study in adopted children by Sorensen et all in 1988 – more likely to die from an infectious etiology if biologic parent died from infection before age 50. Not associated with death from infection in adoptive parents • Polymorphisms identified in multiple inflammatory molecules but unclear effect on host response • Gender: M>F
Risk Factors • Comorbidity • Nearly half of all children with sever sepsis have an underlying comorbidity (neuromuscular, CV, respiratory) • Neoplasm associated with greatest number of sepsiis-related deaths among all children • In older children, CV conditions have the highest case fatality rate of all comorbidconditions • Risk of death increases with increasing number of organ dysfunction
Risk Factors • Environmental risk factors • Surgical site infections • 1/3 most commonly reported infection (~15%) • Contaminated procedure, surgery >2hrs, abd or thoracic procedure, present of ≥ 3 discharge diagnoses • Central venous lines • Most often gram + bacteria (staph aureus, staph epi) • GNR 21% • Very young, chronically ill, poor nutritional status, loss of skin integrity, neutropenia • Endocarditis, Urosepsis, Hemodialysis, Osteomyelitis
Pathophysiology • What the bacteria do to us: • Depends on the bacteria • Gram-negative • Lipopolysaccharide (LPS) endotoxin – found in cell wall • Rapidly triggers an inflammatory response from host • Gram-positive • Exotoxins (tetanus, diptheria, botulism) • Endotoxin –like cell wall components (lipoteichoic acid (LTA), peptidoglycan) • Soluble toxins (super antigens) – toxic shock syndrome
Pathophysiology • What we do to fight the bacteria: • First the pathogen is identified by our innate immune system (macrophages, neutrophils) by specific receptors (Toll-like receptors) • These receptors trigger production of proinflammatory gene elements • Activation of innate immune cells and enhancement of pathogen internalization and intracellular killing
Pathophysiology • What we do to fight the bacteria: • Release of cytokines (TNF-α, IL-1) and chemokines which modulate the inflammatory response • Of interest – anti-inflammatory cytokines are produced as well (TGF-β, IL-1 receptorantagonist, IL10 ) • Activation of adaptive immune system (T- and B-lymphocytes) • More cytokines released (able to produce both pro- and anti-inflammatory) • Activation of the endothelium results in more cytokine release
Pathophysiology • End organ results • Endothelium • Increase in vascular permeability -> capillary leak • Vasodilation • Coagulation cascade • DIC – both bleeding and microvascular clots • Myocardial dysfunction • Temperature regulation • Fever
Clinical presentation of Sepsis • Classically early sepsis presents as: • Hyperdynamic and high cardiac output • Warm extremities • Flash cap refill • Widened pulse pressure • Fever • Ill appearing • Progression to shock will have findings of end organ dysfunction • Mental status changes (may just be irritability in infants) • Grunting or other signs of impending respiratory failure • Poor urine output • Physical exam and history can give you clues to sites of infection
Clinical presentation of septic shock Surviving Sepsis Campaign 2007 Guidelines for Pediatric Septic Shock
Treatment of sepsis • Early recognition • “Goal directed therapy” to restore tissue perfusion • In 2002 – the first set of clinical practice parameters were published • Updated guidelines were published in 2007 and are what we use today
Initial Antimicrobial Therapy • As noted in the algorithm, antimicrobial therapy should be initiated EARLY • Complex decision for choosing antibiotics and history of child is key • Overall need to start broad spectrum • Should cover MRSA for all children now • If immunosuppressed or at risk like CF, should cover for Pseudomonas • Listeriamonocytogenes and HSV coverage for infants <28 days
Initial Antimicrobial Therapy • Children >28 days of age and normal hosts • Vancomycin PLUS cefotaxime • Consider clinda or metronidazole if suspected GI/GU source • Children >28 days and immunosuppressed • Vancomycin PLUS ceftazidime (or cefepime) • Consider adding aminoglycoside like tobramycin • For Penicillin allergic: • Vancomycin PLUS meropenem • For infants <28 days • Typical is Ampicillin, Gentamicin, and Acyclovir • Think about whether Vancomycin is needed for MRSA coverage
Initial Inotropic Therapy • No one right answer for this • Warm, vasodilated, no known cardiac disease -> NOREPI or EPI • Cool, mottled -> DOPAMINE or EPINEPHRINE • Cardiac disease -> DOPAMINE OR EPINEPHRINE • If one isn’t working, add another • Think about vasopressin if not responding to the catecholamines(Dopa, Epi, Norepi)
Summary of therapy • Keep in mind goals up front • SvO2 70% • Perfusion pressure • CVP ~10-12 • Follow lactate • Early antibiotics • Fluid • Fluid • Fluid • Inotrope • Additional Inotrope • Hydrocortisone • ECMO
ICU monitoring and continued care • Intubation with lung protective mechanical ventilation if necessary • Fluid removal • Diruetics • CRRT or PD • Hemoglobin - >10gm/dl • Now being debated • Glycemic control – start insulin if necessary to keep glucose 100-200 • Nutritional support utilizing enteral route if possible (transpyloric if gastroparesis) • Identifying source of infection and addressing this if possible
Prevention • Vaccination • Following recommendations for reducing CLABSI • Insertion bundle • Meticulous sterile technique went entering line • GET THE LINE OUT • Follow VAP prevention bundle while intubated • Remove all plastic as soon as possible • Talk about lines/tubes/drains every day on rounds and engage bedside nursing to facilitate the above