chapter 146. Septic shock

CHAPTER 146. SEPTIC SHOCK

Sepsis :heterogeneous clinical syndrome that caused by any class of microorganism

ICU care: 51.1% , Ventilator care: 17.3%, Motality: 28.6%

0.7% of ED patients: severe sepsis

 

Pathophysiology

Sepsis occurs when the host immune response fails to control invasive pathogens

The blunted inflammatory response results in apoptosis of key immune, epithelial, and endothelial cells, leading to tissue injury and multi-organ disfunction

Severe : procoagulant and anticoagulant imbalance => DIC(clot, tissue damage, thrombosis of small vessel)

 

Symptoms and & Signs

 

Hyperthermia or hypothermia, tachycardia, wide pulse pressure, tachypnea, and mental status changes are early systemic signs of infection and septic shock

 

Cardiovascular function

In the early stage: the vasodilatory mediators predominate, extremities are warm. Cardiac output and stroke volume are usually well maintained.

 

Pulmonary function

ARDS: acute lung injury : arterial hypoxemia (PaO₂ divided by fraction of inspired oxygen of <300) + bilateral pulmonary infiltrates on CXR s pneumonia, acute heart failure.

 

Renal insufficiency

Acute renal failure with azotemia, oliguria, and active urinary sediment.

 

Hepatic dysfunction

Cholestatic jaundice. Concentrations of transaminase, alkaline phosphatase (one to three times the normal level), and bilirubin (usually not >10 milligrams/dL) increase

 

GI injury

Secondary upper GI bleeding(small %), 1-2mm erosion, stomach, duodenum, Ieus

Hematologic abdnormalities

 

neutropenia or neutrophilia, thrombocytopenia(>30%), and DIC. Neutrophilic leukocytosis

Coagulation abnormalities

 

DIC, is a frequent finding in patients :activation of the extrinsic pathway of clotting.

Increase: PT, PTT, fibrin monomer, D-dimer

Decrease: PLT, fibrin, antithromobin III

 

Endocrine abnormality

Hyperglycemia, Hypoglycemia(less common), Adrenal insufficiency

 

Acid-base balance

Resipratory alkalosis -> Metabolic acidosis, Lactate

 

Cutaneous change

Five categories:

1. Direct bacterial involvement skin, soft tissues (cellulitis, erysipelas, and fasciitis);

2.  hematogenous seeding of the skin or the underlying tissue (petechiae, pustules, cellulitis, ecthyma gangrenosum);

3.  Hypotension and/or DIC (acrocyanosis and necrosis of peripheral tissues);

4. Secondary to intravascular infections (microemboli and/or immune complex vasculitis)

5. Caused by toxins (toxic shock syndrome).

 

Diagnostic Critertia for Sepsis

General

>38.3도, <36도, core to pph. Temp gap >3, HR >90, RR>30, altered mental(<11 GCS), Edema, BST >140 s DM

Inflammatory

WBC >12000, <4000, CRP >2SD, procalcitonin >2 SD

Hemodynamic

SBP<90mmHg, 2SD,  SaVO2<70%, Cardiac index <3.5L/min/m2, Vasoacitve drug

Organ dysfuction

PaCO2 >65 torr,  Acute oliguria(<0.5 mL/Kg/h),0.5>Cr elevation, INR >1.5, aPTT >60s,  Ileus, Plt <100K,  T.bil >4mg/dL

Tissue perfusion

Lactate 3>mmol/L,  Capillary refill decreation, metabolic acidosis BE >5mEq/L

 

Early markers of sepsis

lactate(clearance:prognosis), Procalcitonin(sen:42-97%, spe:48-100%),>CRP, IL-6

 

Treatment

Airway: SaO2 >90%(target), Tidal(6mL/Kg of IBW)

Hemodynamic: NS 0.5L/5-10min(10-20mL/Kg in child) usually ~4-6L

             Invasive monitor(Target  CVP. 8-12mmHg, MAP >65mm, SaSCV >70%)

Inotropics: Dopamine 5-20 microgram/kg/min, Norepinephrine 2.5-20microgram/km/min, alternative epinephrine, Dobutamine

 

Empiric andibiotics: Table 146-4 (Adult)

No obvious source: Imipenem, meropenem 1g IV q8h, Droipenem, Ertapenem + vancomycin

Billary source: Ampicillin/sulbactam, Piperacillin/Tazobactam 4.5g q6h, Ticarcillin/clavulanate

Pneumonia: Ceftriaxone 1-2g IV q24 + Azithromycin 500mg IV, 250mg IV q24(2^nd~)+Levovloxacin, Vancomycin

IV abuse: Vancomycin 1g IV q12h

With Petechial rash(N.meningitidis): Ceftriaxone 2g IV q12h, Cefotaxime

Intra-abdominal: Imipenem, meropenem, doripenem

UTI: Piperacillin/Tazobactam, Imipenem, meropenem 1g q8h, Doripenem, ampicillin+gentamicin

*Neutropenic patient: Ceftazidime 2g IV q8h, cefepime, imipenem, meropenm, piperacillin/tazobactam, vancomycin

Anaerobic source: Metronidazole, Clindamycin

Indwelling device: Vancomycin 1g IV q 12h

Legionella species: Azithromycin, ethythromycin

Asplenic patient:Ceftriaxone 1g IV q24

 

Infection source removal: Catheter(Central, Foley, drain)

Glucose control: BST <150mg/dL

 

Patient c Blood culture positive

rarely represent true bacteremia:

S. aureus, E. coli, P. aeruginosa, S. pneumoniae, Klebsiella pneumoniae, and Candida albicans. Corynebacterium spp., Bacillus spp., and Propionibacterium acnes

May or may not represent pathogen:

Viridans group streptococci, enterococci, and coagulase-negative Staphylococcus, which is the most common organism reported on blood culture notifications

 

An immunocompetent, asymptomatic patient with no significant comorbidities and a preliminary culture result compatible with a contaminant may not need immediate reevaluation, (Warning: return immediately for the onset of any distressing symptoms)