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1

What determine tissue perfusion?

1) CO = SV x HR

2) SV = Preload x contractility

2) SVR = (MAP - CVP)/CO

3) BP = CO x SVR

2

Hypovolemic shock

Reduced venous return, pump is working

Low preload. Low CO

Bleeding, vomiting/diarrhea, and third spacing (burns, bowel obstruction, pancreatitis)

Tachy, ortho hypo, cool skin

Will become hypotensive, low pulse pressure, confused, cold clammy skin due to clamping down of peripheral vessels via increased sympathetic tone

in trauma, assume shock is hypovolemic until proven otherwise

3

First vital organ to succumb to shock?

kidney - in hypovolemic or cardiogenic ( the cold shocks)

Blood shunted away from constricted renal arteries

CRUCIAL to monitor for renal failure. A good urine output is a great sign that treatment is working

4

What factors suppress the tachycardic response in hypovolemia?

Beta blockers

Athletes

Damage to autonomic nervous system (spinal shock)

Never use dextrose-containing solution for resuscitation

5

SIRS criteria

2+ of following:

Temp > 38C or 90
RR > 20 or PaCO2 12 or 10% bands

6

Sepsis

Identifiable source of infection + SIRS

7

Severe sepsis

Sepsis + organ dysfunction

8

Septic shock

Sepsis + cardiovascular collapse (requiring vasopressor support)

9

What kind of bacteria are notorious for causing septic shock?

gram-negative bacteria

E Coli
Kleb
Pseudomonas

Top 3 gram positives are:
Staph aureus
Enterococcus
Coag-neg staph

10

HR issues leading to shock

too slow

too fast (not enough time to fill)

11

Preload issues leading to shock

More blood into heart = more blood out

Volume down
Hemorrhage
Obstruction (tension pneumo, pericardial tamp)

12

Contractility issues leading to shock

HF
MI or myocardial contusion

13

SVR and shock

Massive vasodilation - sepsis/anaphylaxis

Spinal trauma (ANS is lost)

Anesthetics

ANS dysfunction (elderly diabetic)

14

Neurogenic shock

CNS injury causing disruption of sympathetic system, resulting in unopposed vagal outflow and vasodilation.

Hypotension and bradycardia (absence of reflex sympathetic tachy and vasoconstriction)

Usually secondary to spinal cord injury of cervical or high thoracic region

Tx = IVFs - helps to place patient in trendelenburg

Vasopressors - used early if patient unresponsive to fluids

15

End points of resuscitation for shock of any etiology

Normalization of lactate (marker of O2 debt), base deficit, pH

Normalization of mixed venous O2 sat (marker of O2 delivery and extraction) and CO

Urine output (marker of renal perfusion)***

16

Swan Ganz

Measure PCWP (preload) - normal 6-12 - reflecting pressure in LV

If pump is failing, you'll see increased wedge

Risks = infection, arrhythmia, injury of pulmonary artery

17

Mixed venous O2 sat

% of O2 bound to hemoglobin in blood returning to heart

It's the amount of O2 left over after tissues remove what they need

Normal = 60-80%

Low = CO isn't high enough to meet tissue O2 needs

BUT

Rise in setting of increased lactate means we're going to anaerobic (late septic shock or in cell poisoning)

18

Side effects of pressors

If B1 stimulation - arrhythmia
If B2 stimulation - vasodilation therefore hypotension

19

The alpha agonists

Phenylephrine, methoxamine (a1 > a2)

Clonidine, methylnorepinephrine (a2 > a1)

20

The mixed alpha and beta agonists

Norepi a1=a2; B1> B2

Epi a1=a2; B1=B2

21

Beta agonists

Dobutamine B1 > B2

Isoproterenol B1 = B2

Terbutaline, metaproterenol, albuterol, ritodrine B2 > B1

22

Dopamine agonists

Dopamine D1 = D2

Fenoldopam D1 > D2

23

Dobutamine

Strong B1 stimulator (ionotropic/chronotropic) wit mild B2 stimulation (vasodilation)

Causes increase in CO and decrease in SVR

Usually used in: Cardiogenic shock

24

Isoproterenol

Similar to dobutamine

Strong stim of B1 (ionotropic/chronotropic) and B2 (vasodilation)

Increased CO and decreased SVR

Use: Cardiogenic shock with bradycardia

25

Milrinone

Phosphodiesterase inhibitor, which results in increased cAMP. This has positive ionotropic effects on heart and also vasodilates

Increased CO and decreased SVR

Use: HF/Cardio shock

26

Dopamine

Different actions depending on dose

1) Low dose (1-3ug/kg/min) = renal dose. Stimulates dopamine recepters (dilates renal vessels) and mild B1 stim

Use: None

2) Intermed dose (5-10) = cardiac dose. Stimulation of dopamine receptors, moderate stim of B1 (heart ionotropy/chrono) and mild a2 (vasoconstriction)

Result = Increased CO
Use = cardiogenic shock

3) High dose (10-20). Stim D, B1, and strong a1 (vasoconstict)

Result = Big increase in SVR
Use = septic shock (replaced by norepi)

27

Norepinephrine

Strong stim of a1 (vasoconstrict), moderate B1 (heart ionotrope/chrono)

Result: higher SVR and higher CO
Use = septic shock

28

Epinephrine

Strong stim of B1 and B2. Also A1 and A2

Result = Increased SVR +/- Increased CO, bronchodilation

Use = Anaphylaxis, septic shock, cardiopulmonary arrest

29

Phenylephrine

Strong stim of A1 (vasoconstrict)

Result = Increased SVR

Use = septic shock, neurogenic shock, anesthesia-induced hypotension

30

Indications for intubation

Airway protection (GCS