infection and sepsis
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INFECTION AND SEPSIS
Surrounded by pathogens Surrounded by pathogens
Infection is the exceptionInfection is the exception
Protective from infectionProtective from infection Physical barriersPhysical barriers Chemical barriersChemical barriers Immunological functionImmunological function
Physical and ChemicalBarriers to Infection
SkinSkin stronger in hands and feetstronger in hands and feet
sebaceous secretions lower sebaceous secretions lower pHpH
Mucous membranes Mucous membranes ciliary functionciliary function mucous barriermucous barrier acid mileu in stomachacid mileu in stomach
Barriers breached in Surgery
Barriers Breached in Trauma
Immune Defense Humoral defenseHumoral defense
antibodiesantibodies complementcomplement
Cellular defenseCellular defense
CytokinesCytokines potential for deleterious potential for deleterious
effectseffects
Interaction of mechanismsInteraction of mechanisms
Breakdown of Host Defense Physical, chemical and immunological Physical, chemical and immunological
breakdown -act synergisticallybreakdown -act synergisticallye.g. patient withe.g. patient with
diabetesdiabetes immunosuppresionimmunosuppresion surgerysurgery
Potential for deleterious effectsPotential for deleterious effects
Fourniers Gangrene
Commensal Microbial Flora
Important for immune developmentImportant for immune development
Occupy binding sites for pathogensOccupy binding sites for pathogens
Provide mucobacterial barrierProvide mucobacterial barrier
Anerobic bacteriaAnerobic bacteria present in greatest quantity in GITpresent in greatest quantity in GIT Greatest diversityGreatest diversity Prevent invasion by gram neg. Prevent invasion by gram neg.
aerobesaerobes
Breakdown of Host Defense- GIT Flora
Transmigration of bacteriaTransmigration of bacteria Lack of feedingLack of feeding Overuse of antibioticsOveruse of antibiotics Absence of bileAbsence of bile Protein malnutritionProtein malnutrition Immune deficiencyImmune deficiency
ICU patient fed enteralyTo preserve GIT integrity
Infection Manifestation Local signsLocal signs
pain,redness,swelling, warmth loss of pain,redness,swelling, warmth loss of functionfunction
Systemic signsSystemic signs Fever, somnolence, confusion, ileus, Fever, somnolence, confusion, ileus,
hypotensionhypotension
Lab testsLab tests TW, polymorphs, CulturesTW, polymorphs, Cultures
Non infective- causes may manifest as Non infective- causes may manifest as infection infection
Common Infections
Wound infectionWound infection
Initial inoculum overwhelms host defenseInitial inoculum overwhelms host defense Occurs at 5 - 7 days post opOccurs at 5 - 7 days post op
FactorsFactors host - immune suppression, DM, renal host - immune suppression, DM, renal
failurefailure surgeon - techniquesurgeon - technique environment - contaminationenvironment - contamination
Common InfectionsTypes of WoundsTypes of Wounds
1.1. Clean - no viscus, no sterile breachClean - no viscus, no sterile breach
2.2. Clean contaminated - controlled entry into Clean contaminated - controlled entry into viscusviscus
3.3. Contaminated - emergency bowel resection, Contaminated - emergency bowel resection, perforated appendixperforated appendix
4.4. Dirty - heavy contamination / long durationDirty - heavy contamination / long duration
Antibiotics usedAntibiotics used type 2 as prophylaxistype 2 as prophylaxis type 3,4 as treatmenttype 3,4 as treatment
Wound Closure
WoundsWounds
Closure byClosure by primary intentionprimary intention secondary intentionsecondary intention
Timing of closureTiming of closure delayed primary delayed primary
closureclosure secondary closuresecondary closure
Closure by Secondary Intention
Intraabdominal Infection
DefenseDefense Bacterial clearance - stomata between Bacterial clearance - stomata between
mesothelial cells under diaphragm lead to mesothelial cells under diaphragm lead to lymph vesselslymph vessels
Phagocytosis - both resident and recruited Phagocytosis - both resident and recruited phagocytesphagocytes
Sequestration - by fibrin rich inflammatory Sequestration - by fibrin rich inflammatory exudate, with omentum/viscera exudate, with omentum/viscera
Intraabdomianal Infection Signs of peritonitisSigns of peritonitis Pain Pain
sharp in character, well localised at firstsharp in character, well localised at first spreads to surrounding areasspreads to surrounding areas involuntary guarding, rigidityinvoluntary guarding, rigidity absent bowel soundsabsent bowel sounds
PosturePosture lying still, rapid breathing ,no lying still, rapid breathing ,no
movementmovement
General conditionGeneral condition ill, septic, dehydrated, hypotensionill, septic, dehydrated, hypotension
Intraabdominal Infection Usually viscus perforationUsually viscus perforation
colon worse than upper GITcolon worse than upper GIT
Isolates Isolates aerobic - E. Coli, klebsiella other aerobic - E. Coli, klebsiella other
enterobacter, strep, enterococci, enterobacter, strep, enterococci, proteus, pseudomonasproteus, pseudomonas
anaerobic - bacteroides, Clostridiumanaerobic - bacteroides, Clostridium
Treatment is surgical and aggressive Treatment is surgical and aggressive antibiotic treatmentantibiotic treatment
Enterocutaneous Fistula
PneumoniaPneumonia Protein malnourishedProtein malnourished upper abdominal wounds ® poor upper abdominal wounds ® poor
coughcough bed bound - atelectasisbed bound - atelectasis elderlyelderly ventilatorventilator
Occurs from 3 days post opOccurs from 3 days post op careful clinical exam,CXRcareful clinical exam,CXR Routine chest physiotherapyRoutine chest physiotherapy
Common Post Surgical Infections
Urinary Tract InfectionUrinary Tract Infection catheterscatheters dehydrationdehydration
Remove catheters Remove catheters earlyearly
Ensure hydrationEnsure hydration
Antimicrobial therapyAntimicrobial therapy
Common Post Surgical Infections
Catheter and prosthetic devicesCatheter and prosthetic devices I/v canulasI/v canulas central linescentral lines meshmesh
Skin organisms- S aureus, S Skin organisms- S aureus, S epidermidisepidermidis
Aseptic techniqueAseptic technique
Remove if infectedRemove if infected
Common Post Surgical Infections
Less Common Post
Surgical Infections
Necrotising soft tissue Necrotising soft tissue infectioninfection
ParotitisParotitis
SinusitisSinusitis
TonsillitisTonsillitis
Treatment of Infection
General principlesGeneral principles incise and drain pusincise and drain pus
antibiotics as neededantibiotics as needed
debride dead tissuedebride dead tissue
remove foreign bodiesremove foreign bodies
Antibiotic Therapy
ProphylaxisProphylaxis Short course to prevent infectionShort course to prevent infection Must be on board before contaminationMust be on board before contamination Antibiotics with activity against expected Antibiotics with activity against expected
inoculation organismsinoculation organisms Avoid extended spectrum agentsAvoid extended spectrum agents Post op benefit not provenPost op benefit not proven Topical antibiotics - not provenTopical antibiotics - not proven
Antibiotic Therapy
Empirical therapyEmpirical therapy based on clinical informationbased on clinical information search for source must continuesearch for source must continue limit duration of empirical therapylimit duration of empirical therapy use known institution pattern of infectionuse known institution pattern of infection multi agent vs broad agentmulti agent vs broad agent
Antibiotic Therapy
Directed therapyDirected therapy target identified pathogenstarget identified pathogens choose suitable efficacy /minimal choose suitable efficacy /minimal
toxicity agenttoxicity agent cover aerobic and anaerobic if cover aerobic and anaerobic if
likelihood exist for bothlikelihood exist for both extended spectrum as last resortextended spectrum as last resort
Multiple System Organ Failure
AKA - Gram neg. bacterial AKA - Gram neg. bacterial sepsissepsis
30% mortality30% mortality
Healthy and compromised hostHealthy and compromised host
3-13 cases per 1000 3-13 cases per 1000 admissionsadmissions
NosocomialNosocomial
FactorsFactors Host compromiseHost compromise Elderly, disabilityElderly, disability MalnutritionMalnutrition Antimicrobial therapyAntimicrobial therapy Major surgeryMajor surgery Cavity manipulationCavity manipulation Immunosuppression e.g. steroidsImmunosuppression e.g. steroids
Multiple System Organ Failure
MSOF FeverFever Acidosis, hypoxemiaAcidosis, hypoxemia Disordered oxygen and substrate useDisordered oxygen and substrate use HyperglycaemiaHyperglycaemia Decreased systemic vascular Decreased systemic vascular
resistanceresistance Elevated cardiac outputElevated cardiac output HypotensionHypotension
MSOF Evidence for LPS - endotoxinEvidence for LPS - endotoxin
LPSLPS O antigen - specific for each organismO antigen - specific for each organism core LPScore LPS membrane lipid Amembrane lipid A
LPS - EFFECTS non specific polyclonal b cell proliferationnon specific polyclonal b cell proliferation
macrophage activation, cytokine releasemacrophage activation, cytokine release
hypotension, hypoxemiahypotension, hypoxemia
bacterial translocationbacterial translocation
complement and coagulation activationcomplement and coagulation activation
platelet and white cell marginationplatelet and white cell margination
LPS - Mechanism Direct effect of bacteriaDirect effect of bacteria
Indirect (mediated) effectIndirect (mediated) effect trigger macrophages to release TNFa, IL-1, trigger macrophages to release TNFa, IL-1,
IL-6, aIFNIL-6, aIFN TNFa, IL-1, - primary mediators but may TNFa, IL-1, - primary mediators but may
be deleterious in large amountsbe deleterious in large amounts aIFN- causes continued activation of aIFN- causes continued activation of
macrophagesmacrophages Permeability defects in microcirculationPermeability defects in microcirculation ARDS, GUT, Hepatic, renal failureARDS, GUT, Hepatic, renal failure
Problem
A 23 year old man A 23 year old man had a perforated had a perforated appendix. Three appendix. Three days post op this days post op this was his temperature was his temperature chart. What is your chart. What is your interpretation.interpretation.
Problem
What is your choice for antibiotic What is your choice for antibiotic prophylaxis for prophylaxis for
colorectal surgerycolorectal surgery biliary surgerybiliary surgery upper GI surgeryupper GI surgery
Problem
A 75 year old diabetic had an operation for A 75 year old diabetic had an operation for perforated diverticular disease. His wound perforated diverticular disease. His wound was found to be infected on the 5th POD.was found to be infected on the 5th POD.
What factors may have contributed to this?What factors may have contributed to this?