Shock in the Pediatric Patient: or Oxygen Don

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Shock in the Pediatric PatientorOxygen Dont
Go Where the Blood Wont Flow!

• James D. Fortenberry MD FAAP, FCCM
• Medical Director, PICU
• Division of Critical Care Medicine
• Childrens Healthcare of Atlanta

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Objectives

• Define shock and its different categories
• Review basic physiologic aspects of shock
• Describe management of shock including
• oxygen supply and demand
• fluid resuscitation
• crystalloid vs. colloid controversy
• vasopressor support

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Definition of Shock

• Uncontrolled blood or fluid loss
• Blood pressure less than 5th percentile for age
• Altered mental status, low urine output, poor
  capillary refill
• None of the above

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Definition of Shock

• An acute complex pathophysiologic state of
  circulatory dysfunction which results in a
  failure of the organism to deliver sufficient
  amounts of oxygen and other nutrients to satisfy
  the requirements of tissue beds

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SUPPLY lt DEMAND
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Definition of Shock

• Inadequate tissue perfusion to meet tissue
  demands
• Usually result of inadequate blood flow and/or
  oxygen delivery
• Shock is not a blood pressure diagnosis!!

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Characteristics of Shock

• End organ dysfunction
• reduced urine output
• altered mental status
• poor peripheral perfusion
• Metabolic dysfunction
• acidosis
• altered metabolic demands

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Essentials of Life

• Gas exchange capability of lungs
• Hemoglobin
• Oxygen content
• Cardiac output
• Tissues to utilize substrate

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Arterial Oxygen Content
100 mm Hg
PaO2 100 mmHg Partial Pressure
SaO2 97 Oxygen Saturation

Hgb 15 gm/100 mL Hemoglobin

O2 in plasma
O2 bound to Hgb
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Oxygen Delivery
DO2Cardiac Output x 1.34 (Hgb x SaO2) Pa02 x
0.003
O2O2O2O2O2O2
O2O2O2O2O2O2
Oxygen Express
Ca02
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Cardiac Output

• The volume of blood ejected by the heart
  in one minute
• 4 - 8 liters / minute

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Cardiac OutputC.O.Heart Rate x Stroke Volume

• Heart rate
• Stroke volume
• Preload- volume of blood in ventricle
• Afterload- resistance to contraction
• Contractility- force applied

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Cardiac OutputC.O.Mean arterial pressure
(MAP) - CVP/SVR

• To improve CO
• MAP
• CVP
• SVR

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Preload Afterload Contractility
x
Stroke Volume
Heart Rate
Cardiac Output
O2 Content
Resistance
x
x
Arterial Blood Pressure
O2 Delivery
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Classification of Shock

• Hypovolemic
• dehydration,burns, hemorrhage
• Distributive
• septic, anaphylactic, spinal
• Cardiogenic
• myocarditis,dysrhythmia
• Obstructive
• tamponade,pneumothorax

• Compensated
• organ perfusion is maintained
• Uncompensated
• Circulatory failure with end organ dysfunction
• Irreversible
• Irreparable loss of essential organs

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Mechanical Requirements for Adequate Tissue
Perfusion

• Fluid
• Pump
• Vessels
• Flow

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Hypovolemic Shock

• Inadequate Fluid Volume
• (decreased preload)

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Hypovolemic ShockCauses

• Fluid depletion
• internal
• external
• Hemorrhage
• internal
• external

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Cardiogenic Shock

• Pump Malfunction
• (decreased contractility)

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Cardiogenic ShockCauses

• Electrical Failure
• Mechanical Failure
• Cardiomyopathy
• metabolic
• anatomic
• hypoxia/ischemia

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Distributive Shock

• Abnormal Vessel Tone
• (decreased afterload)

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Distributive Shock
Vasodilation
Venous Pooling
Decreased Preload
Maldistribution of regional blood flow
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Distributive Shock

• Causes
• Sepsis
• Anaphylaxis
• Neurogenesis (spinal)
• Drug intoxication (TCA, calcium, Channel blocker)

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Septic Shock
Decreased Pump Function
Decreased Volume
Abnormal Vessel Tone
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Cardiac OutputC.O.Heart Rate x Stroke Volume

• Heart rate
• Stroke volume
• Preload- volume of blood in ventricle
• Afterload- resistance to contraction
• Contractility- force applied

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Clinical Assessment

• Heart rate
• Peripheral circulation
• capillary refill
• pulses
• extremity temperature
• Pulmonary
• End organ perfusion
• brain
• kidney

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Improving Stroke VolumeTherapy for
Cardiovascular Support
Preload
Volume
Inotropes
Contractility
Vasodilators
Afterload
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Septic Shock

• Early (Warm)
• Decreased peripheral vascular resistance
• Increased cardiac output
• Late (Cold)
• Increased peripheral vascular resistance
• Decreased cardiac output

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Assessment of Circulation
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Heart Rate and Perfusion Pressure (MAP-CVP)
Parameters by Age
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Assessment of Circulation
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OBSTRUCTIVE SHOCK

• OBSTRUCTED FLOW

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Obstructive ShockCauses

• Pericardial tamponade
• Pulmonary embolism
• Pulmonary hypertension

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Hemodynamic Assessment of Shock
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Goals of Resuscitation

• Overall goal
• increase O2 delivery
• decrease demand

Treatment
Sedation/analgesia
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Principles of Management

• A Airway
• patent upper airway
• B Breathing
• adequate ventilation and oxygenation
• C Circulation
• optimize
• cardiac function
• oxygenation

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Act quickly,Think slowly.
Greek Proverb
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Airway Management

• Patients in shock have
• O2 delivery
• progressive respiratory fatigue/failure
• energy shunted from vital organs
• afterload

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Airway Management

• Early intubation provides
• O2 delivery and content
• controlled ventilation which
• reduces metabolic demand
• allows C.O. to vital organs

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Therapy
Vagolysis
Heart Rate
?
Chromotropy
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Fluid Choices
Colloid
Crystalloid
Less Filling
Tastes Great !
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CrystalloidsHypotonic Fluids (D5 1/4 NS)

• No role in resuscitation
• Maintenance fluids only

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Fluids, Fluids, Fluids

• Key to most resuscitative efforts
• Give generously and reassess

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CrystalloidsIsotonic Fluids

• Intravascular volume expansion
• Hauser
• crystalloids rapidly redistribute
• Lethal animal model
• NS good resuscitative fluid
• 4x blood volume to restore hemodynamics

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CrystalloidsIsotonic Fluids

• 2 trauma studies
• crystalloids colloids but
• 4x amount
• longer time to resuscitation

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CrystalloidsComplications

• Under-resuscitation
• renal failure
• Over-resuscitation
• pulmonary edema
• peripheral edema

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CrystalloidsSummary

• Crystalloids less effective than equal volume of
  colloids
• Preferred when 1o deficit is water and/or
  electrolytes
• Good in initial resuscitation to restore
  extracellular volume
• Hypertonic solutions however, may act as plasma
  volume expanders

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Fluid Transport
Capillary
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ColloidsAlbumin

• Hepatic production
• MW 69,000
• 80 of COP
• Serum t1/2
• 18 hours endogenous
• 16 hours exogenous

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ColloidsHydroxyethyl Starch (Hespan)

• Synthetic
• Derived from corn starch
• Average MW 69,000
• Stable, nonantigenic
• Used for volume expansion
• Renal excretion
• t 1/2 2-67 hours
• 90 gone in 42 days

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ColloidsHydroxyethyl Starch (Hespan)

• Greater in COP than albumin
• Longer duration of action
• 0.006 adverse reactions
• No effect on blood typing
• Prolongs PT, PTT and clotting times
• Dosage
• 20 ml/Kg/day
• max 1500 ml/day

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Fluid Choices

• Based on
• type of deficit
• urgency of repletion
• pathophysiology of condition
• plasma COP

Tastes Great !
Less Filling
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Fluid Choices

• Crystalloids for initial resuscitation
• PRBCs to replace blood loss

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Fluid Management in Pediatric Septic Shock

• Emphasis on the golden hour
• Early aggressive use of fluids may improve
  outcome
• Titrate-Reassess!

Clinical Practice Parameters, Carcillo et al.,
CCM, 2002
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Alpha-Beta Meter
? ß
Dopamine
Epinephrine
Dobutamine
Norepinephrine
Neosynephrine
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Inotropes
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Dopamine Activity

• 0.5-5.0 mcg/kg/min - dopaminergic receptors
• 2.0-10 mcg/kg/min - beta receptors (inotrope)
• 10-20 mcg/kg/min - alpha and beta receptors
• Over 20 mcg/kg/min - alpha receptors (pressors)

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A Rational Approach to Shock in the Pediatric
Patient
Shock / Hypotension
Volume Resuscitation
Signs of adequate circulation Adequate MAP
NO pressors
Yes
NO
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A Rational Approach to Pressor
Use in the PICU
Signs of adequate circulation Adequate MAP
NO
Dopamine
Inadequate MAP
Dopamine and/or Norepinephrine
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A Rational Approach to Pressor
Use in the PICU
Dopamine and/or norepinephrine
adequate MAP
Dobutamine or Milrinone
CO
Inadequate MAP
low C.O.
tachycardia
epinephrine
phenylephrine??
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New Therapies in Septic Shock

• Steroids
• Vasopressin
• Activated Protein C (Xigris) in septic shock

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Management of Pediatric Septic Shock The Golden
Hour

• First 15 minutes
• Emphasis on response to volume

Clinical Practice Parameters, Carcillo et al.,
CCM, 2002
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Patients dont suddenly deteriorate, healthcare
professionals suddenly notice!

• Anonymous