Research in Progress - PACCM @ PittResearch in Progress Author Jason Stamm Created Date 6/24/2015...
Transcript of Research in Progress - PACCM @ PittResearch in Progress Author Jason Stamm Created Date 6/24/2015...
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Case 1
65 year old female nursing home
resident with a hx CAD, PUD, recent hip
fracture
Transferred to ED with decreased
mental status
BP in ED 80/50
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Case 1
65 year old female nursing home
resident with a hx CAD, PUD, recent hip
fracture
Transferred to ED with decreased
mental status
BP in ED 80/50
This case demonstrates some common risk factors for causes of shock
(ACS from CAD?, bleeding from a peptic ulcer?, PE from immobility?)
and common manifestations of shock (altered mental status, hypotension)
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Shock
• Definition
• Physiology of shock
• Types of shock
• Stages of shock
• Clinical presentation of shock
• A bit on vasopressors, inotropes
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Definition
Inadequate perfusion of tissues which is
insufficient to meet cellular metabolic
needs
There is no set blood pressure, cardiac
output, CVP, urine output, or etc that
defines shock.
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Mechanisms of Hypotension
MAP – mean arterial pressure
Cardiac Output
Stroke Volume
Preload Contractility
SVR
Heart Rate
Dr. Kreit circa 2010
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Mechanisms of Hypotension
Hypotension
Cardiac Output
Stroke Volume
Preload Contractility
SVR
Heart Rate
Dr. Kreit circa 2010
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Compensatory Mechanisms that
maintain MAPLV Preload
Stroke Volume
Cardiac Output
Arterial Pressure
Baroreceptors Sympathetic activity
Heart Rate Contractility
+
+
Arterial constriction
Venous constriction
+
SVR+
Adapted from Dr. Kreit circa 2010
Renin
Angiotensin II
Aldosterone
VasopressinNa and H2O
Retention
+
+
+
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Systemic O2 Delivery
• Regulation of O2 delivery (DO2)
– Normally, via cardiac output (CO) and tissue
extraction
– There is no “normal” cardiac output
– Only adequate or inadequate cardiac output
for given metabolic conditions
Pinsky Chest 2007; 132: 2020
http://www.ncbi.nlm.nih.gov/pubmed/18079239
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Shock Physiology
• Imbalance of O2 delivery and
consumption
• Shock results in inadequate O2 delivery
– Cellular hypoxia → anaerobic metabolism
– ↓ ATP generation
– ↓ ion pumps, membrane function
• Initially, damage is reversible →
eventually there is irreversible injury
– Cell death, organ failure, MOSF, death
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Types of Shock
• 4 major categories – Hinshaw and Cox
• “Volume, pump, container”
– Hypovolemic- volume
• Fluid losses (fistulas, burns), hemorrhage
– Cardiogenic- pump
• Myopathic, arrhythmic, mechanical, thyroid
– Distributive- container
• Sepsis/SIRS, anaphylaxis, neurogenic, adrenal
• Obstructive
• PE, Aortic stenosis, tamponade, tension pneumo
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Types of Shock
Shock Type COCardiac output
PCWPpulmonary capillary
wedge pressure
SVRsystemic vascular
resistance
Hypovolemic ↓ ↓ ↑
Cardiogenic ↓ ↑ ↑
Obstructive ↓ NL or ↑ ↑
Distributive ↑ ↓ or NL ↓
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Septic shock
SIRS HR, WBC (↑,↓), RR (PaCO2), Temp (↑,↓)
Sepsis SIRS with culture+ infection or identified infection
Severe Sepsis Sepsis with organ hypoperfusion or dysfunction
Septic Shock Severe sepsis with hypotension after volume
Refractory Septic Shock Shock requiring high dose pressors after
resuscitation
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Stages of Shock
• Pre-shock (“compensated shock”)– Homeostatic mechanisms are sufficient
– You may see:
– ↑ HR
– peripheral vasoconstriction
– BP remains nearly normal
• Shock– Homeostatic mechanisms are overwhelmed
– Organ dysfunction first appears
• End organ dysfunction
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Case 2
You are call by a nurse:
“Mrs. Jones is hypotensive”
Step #1 – ?
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Case 2
You are call by a nurse:
“Mrs. Jones is hypotensive”
Step #1 – Go See Patient –
Assess and Treat simultaneously
○ ABCs
IV access, crystalloid volume early
Pulse ox, UOP, central venous and arterial lines
○ H&P clues
Comorbidities, localizing sxs, etc.
Bleeding, cardiac exam, JVP, infection, etc
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Clinical Presentation of Shock
• Signs and symptoms
– Anxiousness, altered mental status
– Tachycardia, tachypnea
– Cool extremities (±in early distributive shock)
– Weak pulses
– ↓ urine output, acidemia (lactate)
– eventually you will see ↓SBP (a late sign)
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Shock Management
• Improve DO2 to “adequate level”
– There are no static values
– It requires a knowledge of CO, vascular tone
– Are they fluid (pre-load) responsive?
– Can assess with:
• Traditional parameters/methods:
• CVP/Fluid challenge) - not always reliable
• Pulse Pressure Variation, Passive leg raising
– If pre-load optimized → is CO adequate?
• Assess SvO2 for tissue oxygenation
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Early Goal Directed
Therapy
“Functional Hemodynamic
Monitoring”
- early aggressive
resuscitation
- end point of improved
tissue oxygenation
- multicenter trials
ongoing
Rivers et al. NEJM 2001; 345:1368
http://www.ncbi.nlm.nih.gov/pubmed/11794169
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A bit on vasopressors and
inotropes:
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Adrenergic receptors
ADRENOCEPTORS
α1
- Vasoconstriction
- Increased peripheral resistance
- Increased blood pressure
α2
- Inhibition of norepinephrinerelease
β1
- Tachycardia
- Increased myocardial contractility
β2
- Vasodilation
- Decreased peripheral resistance
- Bronchodialation
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Vasopressor parmacology
α1 β1 β2 DA MAP PCWP CO SVR HR
Dopamine
10 mcg/kg/min +++ ++++ + 0 ↑↑ ↑ ↑ ↑ ↑↑
Norepinephrine
0.01-3 mcg/kg/min +++++ ++ 0 0 ↑↑↑ ↑↑ ↑↓ ↑↑↑ ↑↑
Phenylephrine
0.5-9 mcg/kg/min +++++ 0 0 0 ↑ ↑ ↑↓ ↑ NA
Vasopressin
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Inotrope pharmacology
α1 β1 β2 MAP PAP CO SVR HR MOC
Dopamine
3-10 mcg/kg/min 0/+ ++++ ++ ↑ ↔↑ ↑ ↔↓ ↑ ↑
>10 mcg/kg/min +++ ++++ + ↑↑ ↑ ↑ ↑ ↑↑ ↑
Dobutamine
2-20 mcg/kg/min + ++++ +++ ↓ ↓ ↑↑ ↓ ↑↑ ↑
Epinephrine
0.01-0.1 mcg/kg/min +++++ ++++ +++ ↑↑ ↑↑ ↑↑ ↑ ↑↑ ↑
Milrinone
0.125-0.75 mcg/kg/min
PDE-3 inhibitor ↓↓ ↓↓ ↑↑ ↓↓ ↑ ↔↑
Circulation 2008;118:1047-56
Crit Care Med 2008;36:S106-11
MOC; myocardial oxygen consumption
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What pressor to chose?
De Backer D. NEJM 2010
http://www.ncbi.nlm.nih.gov/pubmed/20200382
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More adverse events with
dopamine
De Backer D. NEJM 2010
http://www.ncbi.nlm.nih.gov/pubmed/20200382
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Vasopressors and Inotropes
• Clinical considerations with pressors
– Ensure fluid replete
– Treating people with pressors who are
hypovolemic can cause digital and organ
ischemia
– pH ≥ 7.0 to 7.1
– Pressor-receptor interaction is poor with
acidosis. May need to give buffer to get pH
up.
– Central line preferable
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Take Home Messages
Shock = inadequate tissue oxygen delivery
Cardiogenic, hypovolemic, distributive, obstructive
Treat patient at the bedside
Treat underlying cause, make sure volume replete, and use pressorsjudiciously