Nosocomial infections etc - sepsis etc

Question 1

What is SIRS, sepsis and septic shock? How do they differ?

What is infection and bacterimia?

Answer 1

SIRS = systemic inflammatory response syndrome

2 or more of:

• HR > 90 bpm
• T <36C or >38C
• RR >20 or PaCO2 <32 mm
• WBC <4,000 or > 12,000 cu mm or >10% band form

Sepsis = SIRS + presumed/confirmed infectious process (identified infection!)

Severe sepsis = sepsis + end organ failure

we care because severe sepsis is deadly 35-50%, major cause of death in ICU

Septic shock = sepsis + hypotension = SIRS + presumed/confirmed infectious process + refractory hypotension

Infection = inflammatory response due to a presence of a microorganism or invasion of normally sterile tissue by those organisms

Bacteremia = viable bacteria in the blood

Question 2

How do we get organ dysfunction in sepsis?

Answer 2

infection -> inflammatory mediators -> NO release -> vasodilation -> hypotension -> low vascular perfusion to the organ -> ischemia of the organ -> cell death -> organ dysfunction

OR

infection -> endothelial damage and dysfunction -> edema or microvascular plugging -> maldistribution of vascular flow -> low perfusion -> ischemia -> cell death-> organ dysfunction

Question 3

What are top 5 organisms isolated in septic shock?

think mnemonic about singing…

Answer 3

Every South Korean Singer got Pseudonym

Every Sex Slave Kneels and Plays

E.coli Strep Klebsiella Staph Pseudomonas

Question 4

Clinical features of sepsis? think symptoms…

Answer 4

Tip: start thinking about definitions of SIRS, sepsis and septic shock ….

septic shock: hypotension:

* hypotension

* confusion (brain hypoperfusion)

* end organ dysfunction (organ hypoperfusion)

* reduced vascular tone

SIRS:

* tachycardia (HR> 90)

* tachypnea (RR > 20)

* fever (T> 38)

* leukocytosis WBC <4,000> 12,000

Question 5

What is hyperdynamic state= warm shock?

Answer 5

warm shock = think shock = always low BP, but warm, meaning circulation still working - heart still trying

• tachycardia
• elevated or normal cardiac output
• decreased systemic vascular resistance

Question 6

What is hypodynamic state = cold shock?

Answer 6

cold shock

this time, cold, so no good vascular output =heart not trying, so just

• low cardiac output
• low blood pressure

Question 7

Clinical signs of septic shock (vs sepsis earlier)?

Answer 7

what do we know already? low bp -> low O2 to tissues

• myocardial depression (low perfusion, including cardiac perfusion)
• altered vasculature (dah, vasodilatory)
• altered organ perfusion (lack of pressure - > lack of good blood flow)
• imbalance of O2 delivery and perfusion (lack of pressure - > lack of blood flow -> not enough O2)
• metabolic (lactic) acidosis (not enough O2 -> lactic acidosis as can’t go into Kreb’s so produce lactate from glucose instead)