Principles of Surgery PGY 1 and PGY 2

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Principles of Surgery - PGY 1 and PGY 2 SHOCK
EVIDENCE BASED
Sandro Rizoli, MD, FRCSC, PhD Assistant Professor
Surgery and Critical Care Medicine
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GOAL
1. Preparation for the exams 2. Theoretical
basis for practice
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MASTER PLAN

• Definition
• Classification
• History
• Pathophysiology
• Hypovolemic Shock
• Therapy
• Unresolved issues
• Septic shock
• Definition
• Current guidelines

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QUESTION 1
With regards to the distribution and composition
of the body fluid compartments, which of the
following statements is/are correct? a) Most
intracellular water is in skeletal muscle. b) The
major intracellular cation is sodium. c) The
major intracellular anions are proteins and
phosphates. d) The major extracellular cation is
sodium.
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DEFINITION

• Inadequate tissue perfusion
• Imbalance between substrate supply (DO2)
• and demand (VO2) at a cellular level
• Dysfunction of cellular biochemistry
• cell membrane pump dysfunction
• intracellular edema
• leak intracellular contents
• inadequate regulation intracellular pH

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DEFINITION

• Initially reversible
• Cell death organ damage failure MO death
• Mortality
• septic shock 35-40 mortality
• cardiogenic shock 60-90 mortality
• hemorrhagic variable mortality

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DETERMINANTS TISSUE PERFUSION
DO2 CaO2 x cardiac output VO2 (CaO2 - CvO2)
x cardiac output CO HR x stroke volume
(preloadcontractilityafterload) O2 content
(1.38 x Hg) x O2 sat (0.03 X PaO2 ) SR
vessel length, blood viscosity, vessel diameter
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CLASSIFICATION

• Hypovolemic decreased pre-load
• hemorrhage/fluid loss
• 2. Septic distributive, vasodilatory
• pancreatitis, anaphylaxis, Addison, SIRS
• 3. Neurogenic
• 4. Cardiogenic pump failure
• heart, arrhythmias, obstructive (PE
• pneumotx, tamponade, pulm. hypert.)

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CLASSIFICATION
PCWP CO SVR SVO2 Hypovolemic
Distributive Cardiogenic
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History Shock Resuscitation
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QUESTION 2
Metabolic effects of the neuroendocrine response
to injury include which of the following
events? a) Gluconeogenesis. b) Glycogen
synthesis. c) Lipolysis. d) Proteolysis. e)
Hypoglycemia.
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PATHOPHYSIOLOGY I
Hypovolemia (decresase C.O.)
Vasoconstriction Tachycardia

• Decrease blood flow
• Splanchnic
• Loss gut barrier
• Renal redistribution
• Renin-angiotensin-aldost

Fall transmemb potential Na-K pump
Cellular dysfunction
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PATHOPHYSIOLOGY I
Intracellular water 6
Na9.9 K173 Cl3.9
Na18.4 K162 Cl11.1
Extracellular water 49
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QUESTION 3
Which of the following is/are elevated during
acute response to injury? a) Glucagon. b)
Glucocorticoids. c) Cathecolamines. d)
Insulin. e) Thyroid stimulating hormone (TSH).
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PATHOPHYSIOLOGY II
hypovolemia tissue injury pain fear
sympatho- adrenal response
hypothalamic- hypophyseal- adrenal response
catechol BP, HR contractility vasoconstriction
cortisol, glucagon
hypoxia endoth macrophages cytokines, PAF,
eicosanoid, neutrophils
ROS, coagulation reperfusion injury SIRS/MODS tra
nslocation
hypermetabolic state
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CONSEQUENCES

• Acidemia low pH, lactate, BE
• Ischemic organs
• SIRS
• MODS

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HYPOVOLEMIC SHOCK

• Classification and diagnosis
• 15 compensated
• tachycardia, resp rate, U.O., BP, mental,
  acidosis
• 30
• 40
• gt40

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Surgery
Direct control of bleeding - surgery -
cauterization - topical agents -
angio-embolization
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Fluids
Restore circulating volume - crystalloids -
colloids
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Blood
Replace blood losses - RBC - other blood
products
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Limitations
Direct control of bleeding surgery -
inaccessible requires hours cauterizatio
n - requires dry surface topical - requires dry
surface angio-embolization - not
available unsuitable
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Limitations
Restore circulating volume dilute coagulation
factors hyperchloremic acidosis hypothermia
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Limitations
Replace blood losses limited availability keepi
ng pace with blood loss lab support cost risks
hypothermia
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Diffuse Coagulopathy

• dilutional coagulopathy
• platelet dysfunction and reduction
• hypothermia
• excessive fibrinolysis
• systemic activation coagulation
• and fibrinolysis

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Triangle of Death
massive transfused (10-20U RBC)
hypothermia
death
acidosis
coagulopathy
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Consequences of Transfusion in Trauma
Units of pRBCs and infection in trauma1
Units of pRBC in the first 12h and the MOF in
trauma2
Claridge JA et al. Am Surg 200068566-72 Moore
FA et al. Arch Surg 1997132620-4
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NOVEL THERAPIES

• rFVIIa
• Blood substitutes
• Hypertonic saline

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QUESTION 4
Which of the following statements accurately
characterizes fluid shifts in hemorrhagic
shock? a) Loss of IV volume is fully
compensated by the movement of EC interstitial
fluid into the vascular space. b) Intracellular
fluid volume decreases as fluid shifts from the
IC to the EC compartment to compensate for the IV
loss. c) There is movement of interstitial fluid
into the IC space even though full compensation
of IV losses has not yet occurred. d)
Transmembrane potential falls resulting in
increased Na permeability and influx of Na into
the cell.
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UNRESOLVED ISSUES
1. single most important factor 2. end goals
resuscitation 3. timing resuscitation 4. how much
fluid 5. what fluid
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Guidelines ATLS Endpoints Trauma Room
85 inadequate tissue O2
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Current Resuscitation
Endpoints ICU global supranormal
DO2 mixed venous O2 sat RVEDV - LVP base
deficit lactate regional gastric
tonometry skin/brain blood flow
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THERAPY
Survivors normal or increased CI DO2 V
O2 (lower venous O2 sat) Non-survivors poor
compensation MODS most common cause of death
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THERAPY
GOAL-DIRECTED SUPRANORMAL VALUES Shoemaker (late
80s) post op, trauma pre-op patients Boyd
Hayes (1999) no improvement overall reduced
mortality if 8-12h (8RCT) 92 survival if
achieved 24h 93 mortality if not and lactate
high gt24h
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QUESTION 5
Which one or more of factors determines cardiac
output? a) End-diastolic volume. b)
Afterload. c) Contractility. d) Heart rate. e)
Ventricular interaction.
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UNRESOLVED ISSUES
1. single most important factor 2. end goals
resuscitation 3. timing resuscitation 4. how much
fluid 5. what fluid
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• 598 patients
• penetrating
• BP ? 90 mmHg

• NO FLUID
• n 289
• 90 cc p.h.
• 280 cc ER

• STANDARD
• n 309
• 870 cc p.h.
• 1608 cc ER

62 survived
70 survived
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TIMING for fluids active bleeding EARLY
surgical hemostasis
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QUESTION 6
Which one or more of the factors directly affect
oxygen delivery? a) Blood transfusions. b)
Oxygen consumption (VO2). c) Cardiac output
(CO). d) Fraction of inspired oxygen (FiO2).
e) Metabolic alkalosis.
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SEPTIC SHOCK
Definition SIRS Sepsis systemic response to
infection Severe sepsis lactic acidosis,
oliguria, mental Septic shock hypotension
despite fluids
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DEFINITION SIRS

• At least two of
• RRgt20 or PaCO2lt32mmHg
• HRgt90
• Temperature gt380C or lt360C
• WBCgt12,000 or lt4,000

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THERAPY SEVERE SEPSIS or
SEPTIC SHOCK

• FLUIDS
• DIAGNOSIS
• SOURCE CONTROL
• ANTIBIOTICS

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THERAPY SEVERE SEPSIS or
SEPTIC SHOCK

• FLUIDS
• bolus
• CVP 8-12
• MAP ? 65
• U.O. ? 0.5cc/h
• SvO2 ? 70

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Rivers NEJM 2001
control CVP, MAP, U.O.
intervention CVP, MAP, U.O., SvO2
more fluid more blood more inotropes
0 to 6h
more fluid more blood more inotropes MORE DEATHS
7 to 72h
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THERAPY SEVERE SEPSIS or
SEPTIC SHOCK

• 5. PRESSOR (2nd line, nor, epi or dopamine)
• 6. INOTROPES (dobutamine)
• 7. STEROIDS (ACTH, low raise lt9mcg/dl hemod
  effect)
• rhAPC (PROWESS APACHEgt25, MOD x2
• ADDRESS not for low risk death)

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THERAPY SEVERE SEPSIS or
SEPTIC SHOCK

• 9. TRANSFUSION TRIGGER
• PROTECTIVE VENTILATION
• TV 6ml/k PPlt30, PEEP
• 11. SEDATION, PARALYSIS
• 12. NUTRITION, GLUCOSE CONTROL

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CONCLUSIONS

• Shock
• Definition
• Overview physiopathology
• Hypovolemic shock
• Stop bleeding then volume
• Novel therapies
• Septic shock
• Definition
• Current guidelines