Shock Flashcards
1-understand different types of shock 2-understand similarities & differences in various type of shock 3-ID at least 3 sympathetic reflex compensatory mechanisms in shock 4-ID percent blood loss for the three phases of hemorrhagic shock 5-understand how to ID & tx shock 6-understand the specific features of septic shock
The definition of shock
inadequate tissue perfusion
supply<VO2)
What is the eventual result of shock (2)
anaerobic metabolism->acidosis
decreased cardiac output & acidosis->HYPOtension
Delivery of oxygen is a direct function of what?
cardiac output (CO) and the arterial oxygen content (CaO2) DO2=COxCaO2
Which 3 things are direct determinants of blood pressure?
Cardiac output
preload
peripheral vascular resistance
Ohm’s law
BP=flow(Q)x Resistance (R)
Clinical features of shock
Tachycardia
Tachypnea
+/- hypotension
Signs of poor end-perfusion (altered mental status, oliguria, lactic acidosis, cool, mottled extremities, thread pulses)
signs of poor end perfusion (4)
- altered mental status
- oliguria
- lactic acidosis
- cool, mottled extremities, thread pulses
How can you increase supply? (DO2)
maximize CO -preload -afterload -increase contractility -appropriate HR Maximize CaO2 [arterial oxygen content] -Hct -supplemental O2
Causes of cardiogenic shock (3)
decreased function
arrhythmia
obstruction
Causes of hypovolemic shock (6)
Hemorrhage (GI bleed, trauma, ruptured aneurysm, post-operative) Over-diuresis Diarrhea Dehydration Diabetic ketoacidosis Burns
Causes of septic shock (4)
- positive blood cultures of any organism in 40-70%
- widespread endothelial injury
- decreased peripheral vascular resistance cause hypotension
- other findings: tachycardia, fever, leukocytosis, abnormal clotting parameters, acidosis, renal dysfunction
Other causes of shock
anaphylactic neurologic-spinal cord injury pulmonary embolus Addisonian crisis myxedema
Which form of shock has a LOW A-VO2 difference?
Septic shock
Hypovolemic shock definition
reduction in intravascular volume/preload leading to DECREASED CO & insufficient O2 delivery to cells (mitochondria)
-loss of circulating blood volume (plasma)
Normal blood volume (adult, kid)
70Kg adult=5.5 liters (approx. 15 units)
10kg toddler=900ml
possible etiologies of non-hemorrhagic hypovolemic shock (5)
Excessive GI losses (vomiting, diarrhea) Dehydration Evaporative (burns) Third-Space Losses Neurologic/Renal-diabetes insipidus/melitus
possible etiologies of hemorrhagic hypovolemic shock (4)
- Internal bleeding (GI tract, soft tissues, retroperitoneum-can be hard to detect)
- external bleeding (trauma)
- operative
- iatrogenic (open c-line, aline)
What word should not be used in shock?
STABLE is for horses, if patients are bleeding, they are NEVER stable
What is the body’s response to hypovolemic shock?
Compensated shock->baroreceptor mediated vasoconstriction
-increased Epi, vasopressin, angiotensin
results in:
-tachycardia
-tachypnea
-NARROWED PULSE PRESSURE (under 15-20 is very concerning
-slightly lowered urine output
compensated hemorrhagic shock:
how much blood loss
what happens to BP?
0-20% blood loss
BP is maintained via ↑ vascular tone & ↑blood flow to vital organs
↑ contractility maintains SV +slight↑ in HR maintains near normal CO
vasoconstriction maintains near normal BP
5 compensations in non-progressive (compensated) shock
- baroreceptor reflexes
- renin release
- ADH release
- Epi & Norepi Release
- Compensatory Mechanisms effective
In hypovolemic shock, the body will make whatever adjustments it can to maintain ______________.
Who wins? who loses?
Adequate Cardiac Output
more important organs remain normal, less critical organs are stressed by ischemia
WINNERS: brain, heart, kidneys, liver
LOSERS: skin, GI tract, skeletal muscle
Progressive (un-compensated) shock
- intravascular volume deficient exceeds heart capacity to maintain CO->INADEQUATE PRELOAD->HR ↑
- sympathetic & neurohormonal response no longer able to maintain enough vasoconstriction to maintain systemic perfusion pressure (P=CO*PVR)
- ACIDOSIS, CHANGE IN MENTAL STATUS, POOR URINE OUTPUT EVIDENT
What is evident in progressive (Un-compensated) shock (3)
acidosis
change in mental status
poor urine output
problem with cuff pressures in obesity
cuff pressures may falsely over-estimate pressure, difficulty with palpable pulses, difficult airway
Relative Hypovolemic Shock (3)
- Tension Pneumothorax
- Spinal Shock
- Early Septic Shock
Cardiogenic shock: simple def
pump failure possibly due to CAD, myocardial loss or arrhythmia
progression of Cardiogenic shock
acute hypotension->low CO->
inadequate LV outflow-> poor end organ perfusion!
(same signs/sxs you see in other shock, just a different cause)
Causes of Cardiogenic Shock (9)
- Acute exacerbation of cardiomyopathy
- Acute MI
- Acute myocarditis
- Acute Ventricular Septal or Left Ventricular Rupture
- Acute Aortic Insufficiency-Aortic Dissection
- Cardiac Tamponade 2* pericardial effusion
- Arryhythmia
- Meds: Anti-HTN, AV blockin meds
- Acute Mitral Regurg (papillary m. rupture, ruptured chordae)
Clinical manifestations of cardiogenic shock (9)
hypotension BP<90/60 or 80/60 tachypnea tachycardia pallor, mottled skin restlessness confusion, altered mental status weak pulses cold, clammy extremities oliguria
Tx of cardiogenic shock
tx underlying cause inotropes &/or vasopressors fluids if appropriate intraaortic balloon counterpulsation revascularize if acute MI: -fibrinolyrics (tPA, streptokinase) -angioplasty -CABG
Septic shock: definition/description
exaggerated endogenous inflammatory response to invasive infection leading to:
-circulatory collapse
-multiple organ failure
-death
mortality over 35% (sepsis w/hypotension)
Cardiac output in fluid resuscitated septic shock is
increased
initially they are hypovolemic, but once you put fluid in them, they are in a high output state
Systemic Inflammatory Response Syndrome (SIRS) definition
response to a variety of severe clinical insults, manifested by 2 OR MORE of the following:
- temp>38*C or90bpm
- RR>20 or PaCO212,000/mm3, 10% immature (band) forms “left shift”
Infection Definition
inflammatory response to microorganisms or invasion of normally sterile tissues
Sepsis definition
systemic response to infection-i.e. confirmed or suspected infection PLUS > or = 2 SIRS criteria
Severe Sepsis Def
-sepsis a/w organ dysfxn, hypoperfusion or hypotension
hypoperfusion abnormalities may include but are not limited to: lactic acidosis, oliguria, acute alteration in mental status
Septic Shock: ACCP/SCCM def
sepsis-induced hypotension DESPITE ADEQUATE FLUID RESUSCITATION along w/ perfusion abn (incl. lactic acidosis, oliguria, or acute alteration of mental status)
patients receiving inotropic or vasopressor agents may not be hypotensive at the time perfusion abnormalities are measured
G+ vs. G- sepsis presentation
G+ may have less hypotension than with G- sepsis
What is ARDS
adult respiratory distress syndrome
-inflammatory response where you get leaky capillaries in lungs, lungs become stiff (can occur in sepsis/septic shock, blood transfusion), hard to ventilate, very poor oxygenization
MSOF- multisystem organ failure
Hepatic: transaminitis,↑bilirubin
Renal: ATN, uremia, oliguria progressing to anuria
Pulmonary: ARDS, infections
Cardiac: myocardial depression, arrhythmias
Neuro: altered mental status, confusion, delirium, coma
Others: immune, hematopoietic, coagulation
Warm (hyperdynamic) shock clinical manifestation
hypotensive, tachycardia, tachypnea
- BOUNDING PULSE
- WARM, WELL PERFUSED EXTREMITIES
- SKIN FLUSHED, MOIST
Cold (hypodynamic) shock
hypotensive, tachycardia, tachypnea
- NARROW, THREADY PULSE
- COLD, POORLY PERFUSED EXTREMITIES
- SKIN PALE, DRY
Septic Shock hemodynamics
CVP doesn’t accurately estimate ventricular filling in the critically ill
- when PWP (pulmonary wedge pressure) is appropriately elevated to 12-15 mmHg w/fluid resuscitation, 90% of pts w/septic shock exhibit hyperdynamic circulatory state
- hyperdynamic state persist to death
hypodynamic septic shock=
inadequately fluid resuscitated septic shock (until PWP shows filling pressures btwn 12-15mm Hg)
[if you adequately resuscitate (6-8L saline), they have a better chance]
Metabolic derangement in sepsis
↑ lactate, ↑ MVO3
- micro-anatomic shunts (non-nutritive capillaries)
- functional shunts (impaired micro-circulatory vasomotor contro)
- citric acid (Kreb’s) cycle defect w/anaerobic glycolysis
- aerobic glycolysis w/lactate production
Tx of septic shock
- FluidResuscitation(CVP8‐12,PCWP12‐15)
- IVAntibioticsbroadspreaduntilsourceidentified
- Decreasemetabolicdemands
- Supportbloodpressure,vasoconstrictorsafterfluids
- VentilatorySupport‐ventilator,sedation
- CardiacSupport‐inotropesinsomecases,monitor cardiacoutputandmaximizeit
- NutritionalSupport
- WatchoutforDIC
Classes of hypovolemic shock: blood loss, systolic BP, pulse pressure, pulse, mental status
Class I: 40% blood loss (>2000cc), dec to absent SBP, dec. PP, very tachycardic, lethargic