Shock
Dr. Faiez Alhmoud
Department of Surgery
Albashir Hospital
Objectives
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To develop an understanding of the definition and
pathophysiology of shock
To develop an understanding and overview of the
different types of shock
To develop a systematic approach to the detection
and management of shock
To develop a deeper understanding of sepsis and
septic shock
To know how to decrease mortality in shock
Definition of Shock
What is shock?
Inadequate tissue
perfusion
Why should you care?
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High mortality - 20-90%
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Early on the effects of O2 deprivation
on the cell are REVERSIBLE
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Early intervention reduces mortality
Understanding Shock
Shock results from an inadequate perfusion
of the body’s cells with oxygenated blood.
Which means :
Systemic imbalance between O2 supply & demand
Which leads to:
Cellular dysfunction and damage
 Organ dysfunction and damage

Understanding Shock
Tissue perfusion is driven by blood
pressure!
So………………
 In other words, when the
blood flow (pressure) and
O2 delivery to the cell are
too low, there will be shock!
Understanding Shock -BP
BP = CO x SVR
BP = blood pressure
CO = cardiac output
SVR = systemic (peripheral) vascular resistance
If the blood pressure is low,
then either the:
CO is low or
the SVR is low
Understanding Shock -VR
SVR regulated by blood vessel tone.
 Dilatation opens blood vessels &
increases volume to area but
decreases return to heart
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Constriction decreases volume to area
but increases return to heart
Understanding Shock
Stroke Volume
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Volume of blood pumped by the heart
in one cycle
What affect stroke volume ?
Blood volume
Rhythm problems
Heart muscle problem
Mechanical obstruction
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1234-
Understanding Shock
Blood Volume
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What makes up the blood volume?
1234-
Plasma
RBCes
Platelets
WBCes
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What alters blood volume ?
1- Hemorrage
2- Plasma loss
3- Redistribution of extracellular volume
Stages of shock
Initial :The cells become leaky and switch to anaerobic metabolism.
 Non-progressive:(compensated stage) Attempt to correct the
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metabolic upset of shock
Progressive: Eventually the compinsation will begin to fail
 Refractory : Organs fail and the shock can no longer be reversed.
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Early Stage of Shock
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Compensation
(Maintain & Restore)
1- Tissue perfusion
2- Oxygenetion
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Symptoms
- Almost asymptomatic
•Pulse may be slightly elevated
•Anxiety /Nervousness
•Dizziness
•Weakness
•Faintness
•Nausea & Vomiting
•Thirst
•Confusion
•Decreased UO
•Hx of Trauma / other illness
•Vomiting & Diarrhoea
•Chest Pain
•Fevers / Rigors
•SOB
Non-Progressive shock :
(Compensated)
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MAP Drops by 10-15mm Hg
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Kidneys Release Renin
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Hormonal changes:ADH, Aldosterone,
epinephrine, norephinephrine
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Vasoconstriction:Vessels are clamping
down
Intermediate or Progressive
Shock (Decompensated)
The mechanisms compensate for
worsening shock will begin to fail.
Cellular dysfunction begins to spiral out of
control, metabolic acidosis worsens
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MAP drops more than 15mmHg
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Hypoxia
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Anoxia
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Ischemia
Refractory; Irreversible
Shock
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Lack of O2
< 70
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Increase in toxins
Difficult to recover from
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Enzyme activity increases
Disintegrating any
remaining organelles
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Tissue anoxia
Generalized cellular death
At this stage organs fail and the shock can no longer
be reversed. Death occurs rapidly.
Types of Shock
Hypovolemic
Blood VOLUME problem
 Cardiogenic
Blood PUMP problem
 Distributive
Blood VESSEL problem
 Obstructive
Extracardiac pump FAILURE problem
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What Type of Shock is This?
• 68 yo M with hx of HTN and DU presents
to the ER with epigastric abdominal pain
with radiation to his back and diziness.
The pt is hypotensive, tachycardic, afebrile,
and with cool skin.
Hypovolemic Shock
Hypo-volemic Shock• Non-hemorrhagic
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Vomiting
Diarrhea
Bowel obstruction, pancreatitis
Burns
Neglect, environmental
(dehydration)
• Hemorrhagic
• Trauma
• GI bleed
• Ectopic pregnancy, post-partum
bleeding
• Massive hemoptysis
• AAA rupture
Blood loss - Plasma Loss - ECF Loss
causes
ATLS classification
of hemorrhagic shock
Class
Pulse
BP
CNS Status
Urine
Output
Blood Loss
I
<100
Normal
Slightly
anxious
>30ml/h
<15%
750cc
II
>100
Normal
Mildly
anxious
15 -20
15%-30%
750-1500cc
III
>120
Decreased
Confused
5 -15
30%-40%
1500-2500cc
IV
>140
Decreased
Lethargic
Nil
>40%
>2500cc
In a normal adult, a tachycardia after blood loss
indicates at least a 15% loss of blood volume
(>750 mls)
Evaluation of Hypovolemic
Shock
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• As indicated
CBC
• CXR
ABG/lactate
• Pelvic x-ray
Electrolytes
• Abd. US (FAST)
BUN, Creatinine
• Abd/pelvis CT
Coagulation studies
• Chest CT
Type and cross-match
• GI endoscopy
• Bronchoscopy
• Vascular radiology
Hypovolemic Shock-
management
• ABCs (Control any bleeding)
• Establish 2 large bore IVs or a central line
• Crystalloids
• Normal Saline or Lactate Ringers
• Up to 3 liters
• PRBCs
• O negative or cross matched
• Arrange definitive treatment
What Type of Shock is This?
• An 81 yo F presents to the ED with
chest infection and altered mental
status. She is febrile to 39.4,
hypotensive with a widened pulse
pressure, tachycardic and with warm
extremities
Septic
Sepsis
• Two or more of SIRS criteria
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Temp > 38 or < 36 C
HR > 90
RR > 20
WBC > 12,000 or < 4,000
• Plus the presumed existence of
infection
• Blood pressure can be normal!
Sepsis,Severe Sepsis and
Septic Shock
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Sepsis:
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Severe Sepsis:
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Septic Shock:
Systemic host
response to infection with
SIRS
Sepsis
plus end-organ dysfunction
or hypo perfusion
Sepsis
with hypotension, despite
fluid resuscitation;
evidence of inadequate
tissue perfusion
Septic Shock
• Sepsis (remember definition?)
• Plus refractory hypotension
• After bolus of 20-40 mL/Kg patient still
has one of the following:
• SBP < 90 mm Hg
• MAP < 65 mm Hg
• Decrease of 40 mm Hg from
baseline
Septic Shock
• Clinical signs:
• Hyperthermia or hypothermia
(Hot – early or cold - late phase)
• Tachycardia
• Wide pulse pressure
• Low blood pressure (SBP<90)
• Mental status changes
• Beware of compensated shock!
• Blood pressure may be “normal”
Pathogenesis of Sepsis
Nguyen H et al. Severe Sepsis and Septic-Shock: Review of the Literature and Emergency Department Management Guidelines. Ann Emerg Med. 2006;42:28-54.
Ancillary Studies
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Cardiac monitoring
Pulse oximetry
CBC, coags, LFTs, lipase, KFT & UA
ABG with lactate
Blood culture x 2, urine culture
CXR
Treatment of Septic Shock
• 2 large bore IVs
• NS IVF bolus- 1-2 L wide open (if no
contraindications)
• Supplemental oxygen
• Empiric antibiotics, based on
suspected source, as soon as possible
• Foley catheter (why do you need
this?)
Treatment of Sepsis
• Antibiotics- Survival correlates with how quickly
the correct drug was given
• Cover gram positive and gram negative bacteria
• Add additional coverage as indicated
• Pseudomonas- Gentamicin or Cefepime
• MRSA- Vancomycin
• Intra-abdominal or head/neck anaerobic infectionsClindamycin or Metronidazole
• Asplenic- Ceftriaxone for N. meningitidis, H. infuenzae
• Neutropenic – Cefepime or Imipenem
Persistent Hypotension
• If no response after 2-3 L IVF, start a
vasopressor (norepinephrine, dopamine,
etc) and titrate to effect
• Goal: MAP > 60
• Consider adrenal insufficiency:
hydrocortisone 100 mg IV
What Type of Shock is This?
• A 34 yo F presents to the ER after dining
at a restaurant where shortly after eating
the first few bites of her meal, became
anxious, diaphoretic, began wheezing,
noted diffuse pruritic rash, nausea, and a
sensation of her “throat closing off”. She
is currently hypotensive, tachycardic and
ill appearing with dyspnea.
Anaphylactic Shock
Anaphylactic Shock
• What are some symptoms of anaphylaxis?
• First- Pruritus, flushing, urticaria appear
•Next- Throat fullness, anxiety, chest tightness,
shortness of breath and lightheadedness
•Finally- Altered mental status, respiratory
distress and circulatory collapse
Anaphylactic Shock - Common Features
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Angio-edema
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Broncho-constriction
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Vasodilatation
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Hypotension
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Urticareal rash
Anaphylactic Shock…
Diagnosis
• Clinical diagnosis
• Defined by airway compromise, hypotension,
or involvement of cutaneous, respiratory, or
GI systems
• Look for exposure to drug, food, or insect
bite
• Labs have no role
Anaphylactic Shock….
Treatment
• ABC’s
• Angioedema and respiratory compromise require
immediate intubation or surgical airway
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IV line, cardiac monitor, pulse oximetry
IVFs, oxygen
Epinephrine****
Second line
• Corticosteriods
• H1 and H2 blockers
Anaphylactic Shock….
Treatment
• Epinephrine
• 0.3 mg IM of 1:1000 (epi-pen)
• Repeat every 5-10 min as needed
• Caution with patients taking beta blockers- can cause severe
hypertension due to unopposed alpha stimulation
• Corticosteroids
• Methylprednisolone 125 mg IV
• Prednisone 60 mg PO
• Antihistamines
• H1 blocker- Diphenhydramine 25-50 mg IV
• H2 blocker- Ranitidine 50 mg IV
• Bronchodilators
• Albuterol nebulizer
• Atrovent nebulizer
• Magnesium sulfate 2 g IV over 20 minutes
Anaphylactic Shock….
Management
• All patients who receive epinephrine
should be observed for 4-6 hours
• If symptom free, discharge home
• If on beta blockers or h/o severe
reaction in past, consider admission
What Type of Shock is This?
• A 41 yo M presents to the ER after a
car accident complaining of decreased
sensation below his waist and is now
hypotensive, bradycardic, with warm
extremities
Neurogenic
Neurogenic Shock
• Neurogenic shock is caused by the loss of
sympathetic control (tone) of resistance
vessels, which leads to decreased tissue
perfusion and initiation of the shock response.
• Results in hypotension and bradycardia
• Neurogenic shock can be caused by spinal cord
injury (above T1), CNS injury, general or spinal
anesthesia, pain, and anxiety.
• Onset is within minutes and may last weeks .
• Skin is warm and dry
Neurogenic Shock…..Treatment
• A,B,Cs
• Remember c-spine precautions
• Fluid resuscitation
• Keep MAP at 85-90 mm Hg for first 7 days
• Thought to minimize secondary cord injury
• If crystalloid is insufficient use vasopressors
• Search for other causes of hypotension
• Methylprednisolone is controversial & given
early and in high doses
• For bradycardia
• Atropine
• Pacemaker
What Type of Shock is This?
• A 55 yo M with hx of HTN,
DM presents with “crushing”
substernal pain, diaphoresis,
hypotension, tachycardia
and cool, clammy extremities
Cardiogenic Shock
• Defined as:
shock resulting from
inadequate cardiac
function
• Signs:
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Cool, mottled skin
Tachypnea, tachycardia
Hypotension
Altered mental status
Narrowed pulse
pressure (WEAK)
• Rales, murmur
Cardiogenic Shock - Etiology
WHAT CAUSES PUMP FAILURE ?
Intrinsic Causes
- Myocardial injury
- Tachycardia
- Valvular defect
 Extrinsic (Obstructive Shock)
- Pericardial tamponade
- Tension pneumothorax
- Large pulmonary emblous
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Pathophysiology of Cardiogenic Shock
• Often after ischemia, loss of LV function
(Loss of 40% of LV function clinical shock ensues)
• CO reduction = lactic acidosis, hypoxia
• Stroke volume is reduced
• Tachycardia develops as compensation
• Ischemia and infarction worsens
Ancillary Tests
• EKG
• CXR
• CBC, cardiac enzymes, coagulation
studies
• Echocardiogram
What Type of Shock is This?
• A 24 yo M presents to the ED after
an MVC c/o chest pain and
difficulty breathing. On PE, you
note the pt to be tachycardic,
hypotensive, hypoxic, and with
decreased breath sounds on left
Obstructive
Obstructive Shock
Obstructive Shock
• Tension pneumothorax
• Air trapped in pleural space with 1 way
valve, air/pressure builds up
• Mediastinum shifted impeding venous
return
• Chest pain, SOB, decreased breath
sounds
• No tests needed!
• Rx: Needle decompression, chest tube
Obstructive Shock
• Cardiac tamponade
• Blood in pericardial sac prevents venous
return to and contraction of heart
• Related to trauma, pericarditis, MI
• Beck’s triad: hypotension, muffled heart
sounds, JVD
• Diagnosis: large heart CXR, echo
• Rx: Pericardiocentisis
Obstructive Shock
• Pulmonary embolism
• Virscow triad: hypercoaguable, venous
injury, venostasis
• Signs: Tachypnea, tachycardia, hypoxia
• Low risk: D-dimer, CT chest or VQ scan
• Rx: Heparin, consider thrombolytics
Obstructive Shock
• Aortic stenosis
• Resistance to systolic ejection causes
decreased cardiac function
• Chest pain with syncope
• Systolic ejection murmur
• Diagnosed with echo
• Vasodilators (NTG) will drop pressure!
• Rx: Valve surgery
TO BE CONTINUED
Clinical Assessment
Is this shock ?
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Head & Neck = Pale ? Cyanosis? Dyspnea?
LOC?, RR?, Peripheral pulses?
Vital Signs Initially: HR inc; RR inc; diastolic
BP inc slightly P02 > 95%
Skin Color; Cap refill; Warm? Cool? Petech.
Pt c/o being thirsty or dry mucous membr.
Renal Drop in output (0.5ml/Kg/h)
In infants :poor tone, weak cry, lethargy/
coma sunken or bulging fontanella)
Shock
•Do you remember how
to quickly estimate blood
pressure by pulse?
•
If you palpate a pulse,
you know SBP is at
least this number
60
70
80
90
Empiric Criteria for Shock
4 out of 6 criteria have to be met
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Ill appearance or altered mental status
Heart rate >100
Respiratory rate > 22 (or PaCO2 < 32
mmHg)
Urine output < 0.5 ml/kg/hr
Arterial hypotension > 20 minutes duration
Lactate > 4
LAB VALUES IN SHOCK
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H&H = decreased in hemorrhage
WBC = increase in Septic &
Anaphylactic shock
Neutrophils = Acute infection
Monocytes = Bacterial infection
Eosinophils = Allergic response
Kidney function Decreased perfusion = BUN & Creatinine,
specific gravity & osmolality increase
Cardiac enzymes (cardiogenic shock) LDH, CPK, SGOT
increase
Lactate
Beta HCG
+/- Cross Match
Other investigations
ECG
 Urinalysis
 CXR
 +/- Echo
 +/- FAST
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Treatment of Shock
Start treatment immediately
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ABC’s “5 to 15”
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Airway
Breathing
Circulation
Put the patient on a monitor if available
Treat underlying cause
Modified Trendelenberg ?
Medications (BP medications Bronchodilators Steroids)
LOOK, FEEL, LISTEN, REPORT
Airway & Breathing
• Give Oxygen
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Consider Intubation
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Is the cause quickly reversible?
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Generally no need for intubation
3 reasons to intubate in the setting of shock
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Inability to oxygenate
Inability to maintain airway
Work of breathing
• Remember: intubation can worsen hypotension
• Sedatives can lower blood pressure
• Positive pressure ventilation decreases preload
• May need volume resuscitation prior to intubation to avoid
hemodynamic collapse
Optimizing Circulation
• DO NOT WAIT for hypotension and
treat for the early signs of shock
• Isotonic crystalloids
• Titrated to:
• CVP 8-12 mm Hg
• Urine output 0.5 ml/kg/hr (30 ml/hr)
• Improving heart rate
• May require 4-6 L of fluids
• No outcome benefit from colloids
End Points of Resuscitation
• Goal of resuscitation is to maximize survival
and minimize morbidity
• Use objective hemodynamic and
physiologic values to guide therapy
• Goal directed approach
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Urine output > 0.5 mL/kg/hr
CVP 8-12 mmHg
MAP 65 to 90 mmHg
Central venous oxygen concentration > 70%
Persistent Hypotension
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Inadequate volume resuscitation
Pneumothorax
Cardiac tamponade
Hidden bleeding
Adrenal insufficiency
Medication allergy
Practically Speaking….
Know how to distinguish different
types of shock and treat accordingly
 Look for early signs of shock
 Monitor the patient using the HR,
MAP, mental status, urine output
 SHOCK is not equal to hypotension
 Start antibiotics within an hour!
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Do not wait for cultures or blood work
The End
Any
Question?
Infusion Rates
Access
18 g peripheral IV
16 g peripheral IV
14 g peripheral IV
8.5 Fr CV cordis
Gravity
50 mL/min
100 mL/min
150 mL/min
200 mL/min
Pressure
150
225
275
450
mL/min
mL/min
mL/min
mL/min