Shock

1
Shock

• Dr. Faiez Alhmoud
• Department of Surgery
• Albashir Hospital

2
Objectives

• 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

3
Definition of Shock

• What is shock?
• Inadequate tissue perfusion

4
Why should you care?

• High mortality - 20-90
• Early on the effects of O2 deprivation on the
  cell are REVERSIBLE
• Early intervention reduces mortality

5
Understanding Shock

• Shock results from an inadequate perfusion of the
  bodys cells with oxygenated blood.
• Which means
• Systemic imbalance between O2 supply demand
• Which leads to
• Cellular dysfunction and damage
• Organ dysfunction and damage

6
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!

7
 
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

8
Understanding Shock -VR

• SVR regulated by blood vessel tone.
• Dilatation opens blood vessels increases volume
  to area but decreases return to heart
• Constriction decreases volume to area but
  increases return to heart

9
Understanding Shock Stroke Volume

• Volume of blood pumped by the heart in one cycle
• What affect stroke volume ?
• 1- Blood volume
• 2- Rhythm problems
• 3- Heart muscle problem
• 4- Mechanical obstruction

10
Understanding Shock Blood Volume

• What makes up the blood volume?
• 1- Plasma
• 2- RBCes
• 3- Platelets
• 4- WBCes
• What alters blood volume ?
• 1- Hemorrage
• 2- Plasma loss
• 3- Redistribution of extracellular volume

11
Stages of shock

• Initial The cells become leaky and switch to
  anaerobic metabolism.
• Non-progressive(compensated stage) Attempt to
  correct the 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

• Compensation
• (Maintain Restore)
• 1- Tissue perfusion
• 2- Oxygenetion
• 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

13
Non-Progressive shock (Compensated)

• MAP Drops by 10-15mm Hg
• Kidneys Release Renin
• Hormonal changesADH, Aldosterone, epinephrine,
  norephinephrine
• VasoconstrictionVessels are clamping down

14
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 
• MAP drops more than 15mmHg
• Hypoxia
• Anoxia
• Ischemia

15
Refractory Irreversible Shock

• Lack of O2
• lt 70
• Increase in toxins
• Difficult to recover from
• Enzyme activity increases Disintegrating any
  remaining organelles
• Tissue anoxia
• Generalized cellular death
• At this stage organs fail and the shock can no
  longer be reversed. Death occurs rapidly.

16
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
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Hypo-volemic Shock- causes

• Non-hemorrhagic
• 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

19
ATLS classification of hemorrhagic shock
In a normal adult, a tachycardia after blood loss
indicates at least a 15 loss of blood volume
(gt750 mls)
20
Evaluation of Hypovolemic Shock

• As indicated
• CXR
• Pelvic x-ray
• Abd. US (FAST)
• Abd/pelvis CT
• Chest CT
• GI endoscopy
• Bronchoscopy
• Vascular radiology

• CBC
• ABG/lactate
• Electrolytes
• BUN, Creatinine
• Coagulation studies
• Type and cross-match

21
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

22
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
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Sepsis

• Two or more of SIRS criteria
• Temp gt 38 or lt 36 C
• HR gt 90
• RR gt 20
• WBC gt 12,000 or lt 4,000
• Plus the presumed existence of infection
• Blood pressure can be normal!

24
Sepsis,Severe Sepsis and Septic Shock

• Sepsis Systemic host response to infection with
  SIRS
• Severe Sepsis Sepsis plus end-organ dysfunction
  or hypo perfusion
• Septic Shock Sepsis with hypotension, despite
  fluid resuscitation evidence of inadequate
  tissue perfusion

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Septic Shock

• Sepsis (remember definition?)
• Plus refractory hypotension
• After bolus of 20-40 mL/Kg patient still has one
  of the following
• SBP lt 90 mm Hg
• MAP lt 65 mm Hg
• Decrease of 40 mm Hg from baseline

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Septic Shock

• Clinical signs
• Hyperthermia or hypothermia
• (Hot early or cold - late phase)
• Tachycardia
• Wide pulse pressure
• Low blood pressure (SBPlt90)
• Mental status changes
• Beware of compensated shock!
• Blood pressure may be normal

27
Pathogenesis of Sepsis
Nguyen H et al. Severe Sepsis and Septic-Shock
Review of the Literature and Emergency Department
Management Guidelines. Ann Emerg Med.
20064228-54.
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Ancillary Studies

• Cardiac monitoring
• Pulse oximetry
• CBC, coags, LFTs, lipase, KFT UA
• ABG with lactate
• Blood culture x 2, urine culture
• CXR

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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?)

30
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
  infections- Clindamycin or Metronidazole
• Asplenic- Ceftriaxone for N. meningitidis, H.
  infuenzae
• Neutropenic Cefepime or Imipenem

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Persistent Hypotension

• If no response after 2-3 L IVF, start a
  vasopressor (norepinephrine, dopamine, etc) and
  titrate to effect
• Goal MAP gt 60
• Consider adrenal insufficiency hydrocortisone
  100 mg IV

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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.

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Anaphylactic Shock
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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

35
Anaphylactic Shock - Common Features

• Angio-edema
• Broncho-constriction
• Vasodilatation
• Hypotension
• Urticareal rash

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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

37
Anaphylactic Shock. Treatment

• ABCs
• Angioedema and respiratory compromise require
  immediate intubation or surgical airway
• IV line, cardiac monitor, pulse oximetry
• IVFs, oxygen
• Epinephrine
• Second line
• Corticosteriods
• H1 and H2 blockers

38
Anaphylactic Shock. Treatment

• Epinephrine
• 0.3 mg IM of 11000 (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

39
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

40
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
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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

42
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

43
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

44
Cardiogenic Shock

• Signs
• Cool, mottled skin
• Tachypnea, tachycardia
• Hypotension
• Altered mental status
• Narrowed pulse pressure (WEAK)
• Rales, murmur

• Defined as
• shock resulting from inadequate cardiac
  function

45
Cardiogenic Shock - Etiology

• WHAT CAUSES PUMP FAILURE ?
• Intrinsic Causes
• - Myocardial injury
• - Tachycardia
• - Valvular defect
• Extrinsic (Obstructive Shock)
• - Pericardial tamponade
• - Tension pneumothorax
• - Large pulmonary emblous

46
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

47
Ancillary Tests

• EKG
• CXR
• CBC, cardiac enzymes, coagulation studies
• Echocardiogram

48
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
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Obstructive Shock
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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

51
Obstructive Shock

• Cardiac tamponade
• Blood in pericardial sac prevents venous return
  to and contraction of heart
• Related to trauma, pericarditis, MI
• Becks triad hypotension, muffled heart sounds,
  JVD
• Diagnosis large heart CXR, echo
• Rx Pericardiocentisis

52
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

53
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

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TO BE CONTINUED
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Clinical AssessmentIs this shock ?

• Head Neck Pale ? Cyanosis? Dyspnea?
• LOC?, RR?, Peripheral pulses?
• Vital Signs Initially HR inc RR inc diastolic
  BP inc slightly P02 gt 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)

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Shock

• Do you remember how to quickly estimate blood
  pressure by pulse?

60
70

• If you palpate a pulse,
• you know SBP is at
• least this number

80
90
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Empiric Criteria for Shock

• 4 out of 6 criteria have to be met
• Ill appearance or altered mental status
• Heart rate gt100
• Respiratory rate gt 22 (or PaCO2 lt 32 mmHg)
• Urine output lt 0.5 ml/kg/hr
• Arterial hypotension gt 20 minutes duration
• Lactate gt 4

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LAB VALUES IN SHOCK

• HH 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

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Other investigations

• ECG
• Urinalysis
• CXR
• /- Echo
• /- FAST

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Treatment of Shock

• Start treatment immediately
• ABCs 5 to 15
• 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

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Airway Breathing

• Give Oxygen
• Consider Intubation
• Is the cause quickly reversible?
• Generally no need for intubation
• 3 reasons to intubate in the setting of shock
• 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

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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

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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
• Urine output gt 0.5 mL/kg/hr
• CVP 8-12 mmHg
• MAP 65 to 90 mmHg
• Central venous oxygen concentration gt 70

65
Persistent Hypotension

• Inadequate volume resuscitation
• Pneumothorax
• Cardiac tamponade
• Hidden bleeding
• Adrenal insufficiency
• Medication allergy

66
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!
• Do not wait for cultures or blood work

67
The End

• Any Question?

68
Infusion Rates

• Access Gravity Pressure
• 18 g peripheral IV 50 mL/min 150 mL/min
• 16 g peripheral IV 100 mL/min 225 mL/min
• 14 g peripheral IV 150 mL/min 275 mL/min
• 8.5 Fr CV cordis 200 mL/min 450
  mL/min