1. Shock
Scott G. Sagraves, MD, FACS
Assistant Professor
Trauma & Surgical Critical Care
Associate Director of Trauma
UHS of Eastern Carolina

2. Objectives
• Define & classify shock
• Outline management principles
• Discuss goals of fluid resuscitation
• Understand the concepts of oxygen
supply and demand in managing shock.
• Describe the physiologic effects of
vasopressors and inotropic agents

3. Goals
• Review hemodynamic techniques in the ICU
• Introduce the concept of the cardiac cycle
• Review of the pulmonary artery catheter
parameters
• Utilize the presentation to analyze clinical
cases and to feel comfortable with pa-c
parameters.

4. Shock:
“A momentary pause in the act of
death.”
-John Collins Warren, 1800s

5. Hypotension
• In Adults:
– systolic BP ≤ 90 mm Hg
– mean arterial pressure ≤ 60 mm Hg
  systolic BP > 40 mm Hg from the
patient’s baseline pressure

6. Definition
SHOCK: inadequate organ perfusion
to meet the tissue’s oxygenation
demand.

7. “Hypoperfusion can be
present in the absence of
significant hypotension.”
-fccs course

8. Pathophysiology
ATP + H2O ⇒ ADP + Pi + H+
+ Energy
Acidosis results from the accumulation of acid
when during anaerobic metabolism the
creation of ATP from ADP is slowed.
H+
shift extracellularly and a metabolic acidosis
develops

9. Pathophysiology
• ATP production fails, the Na+
/K+
pump
fails resulting in the inability to correct
the cell electronic potential.
• Cell swelling occurs leading to rupture
and death.
• Oxidative Phosphorylation stops &
anaerobic metabolism begins leading to
lactic acid production.

10. Why Monitor?
• Essential to understanding their disease
• Describe the patient’s physiologic
status
• Facilitates diagnosis and treatment of
shock

11. History
• 1960’s
– low BP = shock; MSOF resulted after BP
restored
• 1970’s
– Swan & Ganz - flow-directed catheter
– thermistor → cardiac output
• 1980’s
– resuscitation based on oxygen delivery,
consumption & oxygen transport balance.

12. Pulmonary Artery Catheter

13. Pulmonary Artery Catheter
• INDICATIONS
– volume status
– cardiac status
• COMPLICATIONS
– technical
– anatomic
– physiologic

14. PLACEMENT

15. West’s Lung Zones
• Zone I - PA > Pa > Pv
• Zone II - Pa > PA > Pv
• Zone III - Pa > Pv > PA
• PA= alveolar

16. Correct PA-C Position

17. Standard Parameters
• Measured
– Blood pressure
– Pulmonary A.
pressure
– Heart rate
– Cardiac Output
– Stroke volume
– Wedge pressure
– CVP
• Calculated
– Mean BP
– Mean PAP
– Cardiac Index
– Stroke volume
index
– SVRI
– LVSWI
– BSA

18. Why Index?
• Body habitus and size is individual
• Inter-patient variability does not allow
“normal” ranges
• “Indexing” to patient with BSA allows for
reproducible standard

19. Index Example
PATIENT A
• 60 yo male
• 50 kg
• CO = 4.0 L/min
• BSA = 1.86
CI = 2.4 L/min/m2
PATIENT B
• 60 yo male
• 150 kg
• CO = 4.0 L/min
• BSA = 2.64
CI = 1.5 L/min/m2

20. PA Insertion
0
5
10
15
20
RA = 5 RV = 22/4 PA 19/10 PAOP = 9

21. CVP
• CVP of SVC at level of right atrium
• pre-load “assessment”
• normal 4 - 10 mm Hg
• limited value

22. PAOP
• End expiration
• Reflection changes with positive pressure
• Waveforms change ≈ every 20 cm

23. Waveform Analysis
• A wave - atrial systole
• C wave - tricuspid valve closure @
ventricular systole
• V wave - venous filling of right atrium

24. Cardiac Cycle
pulmonary
Left ventricle
systemic
Right ventricleRVSWI
PVRI
LVSWI
SVRI
CVP
MPAP
PCWP
MAP

25. Hemodynamic Calculations
Parameter Normal
Cardiac Index (CI) 2.8 - 4.2
Stroke Volume Index (SVI) 30 - 65
Sys Vasc Resistance Index (SVRI) 1600 - 2400
Left Vent Stroke Work Index (LVSWI) 43 - 62

26. Cardiac Index
C.I. = HR x SVI
SVI measures the amount of blood ejected by the
ventricle with each cardiac contraction.
Total blood flow = beats per minute x blood volume ejected per beat

27. Vascular Resistance Index
SYSTEMIC (SVRI)
MAP - CVP
CI
↑ SVR = vasoconstriction
↓ SVR = vasodilation
PULMONARY (PVRI)
MPAP - PAOP
CI
↑PVR = constriction
PE, hypoxia
x 80 x 80
Vascular resistance = change in pressure/blood flow

28. Stroke Work
LVSWI = (MAP-PAOP) x SVI x 0.0136
normal = 43 - 62
VSWI describe how well the ventricles
are contracting and can be used to
identify patients who have poor
cardiac function.
ventricular stroke work = ∆ pressure x vol. ejected

29. Too Many Numbers

30. Definitions
• O2 Delivery - volume of gaseous O2
delivered to the LV/min.
• O2 Consumption - volume of gaseous
O2 which is actually used by the
tissue/min.
• O2 Demand - volume of O2 actually
needed by the tissues to function in an
aerobic manner
Demand > consumption = anaerobic metabolism

31. Rationale for Improving
O2 Delivery
Insult
Tissue Hypoxia
Increased Delivery
Increased Consumption
Demands are met

32. Critical O2 Delivery
VO2I
DO2I
The critical value is
variable
& is dependent upon the
patient, disease, and the
metabolic demands of the
patient.

33. Oxygen Calculations
• Arterial Oxygen Content
(CaO2)
• Venous Oxygen Content
(CvO2)
• Arteriovenous Oxygen
Difference (avDO2)
• Delivery (O2AVI)
• Consumption (VO2I)
Efficiency of
the
oxygenation
of blood and
the rates of
oxygen
delivery and
consumption

34. Arterial Oxygen Content
CaO2 = (1.34 x Hgb x SaO2) + (PaO2 x 0.0031)
If low, check hemoglobin or pulmonary gas
exchange

35. Arteriovenous Oxygen
Difference
avDO2 = CaO2 - CvO2
Values > 5.6 suggests more
complete tissue oxygen
extraction, typically seen in
shock

36. Oxygen Delivery (DO2I)
O2AVI = CI x CaO2 x 10
Normal values suggests that the heart
& lungs are working efficiently to
provide oxygen to the tissues.
< 400 is bad sign

37. Oxygen Consumption
VO2I = CI x (CaO2 - CvO2)
If VO2I < 100 suggest tissues are not
getting enough oxygen

38. SvO2
SvO2 = 1-
VO2
DO2

39. Oxycalculations

40. Resuscitation Goals
• CI = 4.5 L/min/m2
• DO2I = 600 mL/min/m2
• VO2I = 170 mL/min/m2
NOT ALL PATIENTS CAN ACHIEVE THESE GOALS
Critically ill patients who can respond to their disease states by
spontaneously or artificially meeting these goals do show a
better survival.

41. Break Time…

42. “Shock is a symptom of
its cause.”
-fccs course

43. Signs of Organ
Hypoperfusion
• Mental Status Changes
• Oliguria
• Lactic Acidosis

44. Components

45. Categories of Shock
• HYPOVOLEMIC
• CARDIOGENIC
• DISTRIBUTIVE
• OBSTRUCTIVE

46. Goals of Shock
Resuscitation
• Restore blood pressure
• Normalize systemic perfusion
• Preserve organ function

47. In general, treat the cause...

48. Hypovolemic Shock
• Causes
–hemorrhage
–vomiting
–diarrhea
–dehydration
–third-space loss
–burns
• Signs
  cardiac
output
  PAOP
  SVR

49. Classes of Hypovolemic Shock

50. Treatment - Hypovolemic
• Reverse hypovolemia vs. hemorrhage
control
• Crystalloid vs. Colloid
• PASG role?
• Pressors?

51. Resuscitation
• Transport times < 15 minutes showed
pre-hospital fluids were ineffective,
however, if transport time > 100 minutes
fluid was beneficial.
• Penetrating torso trauma benefited from
limited resuscitation prior to bleeding
control. Not applicable to BLUNT
victims.

52. Fluid Administration
• 1 L crystalloid ≈ 250 ml colloid
• crystalloids are cheaper
• blood must supplement either
• FFP for coagulopathy, NOT volume
• Watch for hyperchloremic metabolic acidosis
when large volumes of NaCl are infused
• NO survival benefit with colloids

53. Role of PASG?
• Houston - Higher mortality rate in penetrating
thoracic, cardiac trauma
• No benefit in penetrating cardiac trauma
• Role undefined in rural, blunt trauma
• Splinting role

54. Cardiogenic Shock
• Cause
– defect in cardiac function
• Signs
  cardiac output
  PAOP
  SVR
  left ventricular stroke work (LVSW)

55. Coronary Perfusion
Pressure
Coronary PP = DBP - PAOP
coronary perfusion = ∆ P across coronary a.
GOAL - Coronary PP > 50 mm Hg

56. The Failing Heart
• Improve myocardial function, C.I. < 3.5 is a risk
factor, 2.5 may be sufficient.
• Fluids first, then cautious pressors
• Remember aortic DIASTOLIC pressures drives
coronary perfusion (DBP-PAOP = Coronary
Perfusion Pressure)
• If inotropes and vasopressors fail, intra-aortic
balloon pump

57. Distributive Shock
• Types
– Sepsis
– Anaphylactic
– Acute adrenal insufficiency
– Neurogenic
• Signs
– ± cardiac output
± PAOP
 SVR

58. SIRS - Distributive Shock
• Prompt volume replacement - fill the tank
• Early antibiotic administration - treat the cause
• Inotropes - first try Dopamine
• If MAP < 60
– Dopamine = 2 - 3 µg/kg/min
– Norepinephrine = titrate (1-100 µg/min)
• R/O missed injury

59. Adrenal Crisis
Distributive Shock
• Causes
– Autoimmune adrenalitis
– Adrenal apoplexy = B hemorrhage or infarct
– heparin may predispose
• Steroids may be lifesaving in the patient
who is unresponsive to fluids, inotropic,
and vasopressor support. Which one?

60. Obstructive Shock
• Causes
– Cardiac Tamponade
– Tension Pneumothorax
– Massive Pulmonary Embolus
• Signs
  cardiac output
  PAOP
  SVR

61. Endpoints?
• ACS CoT ATLS - restoration of vital signs and
evidence of end-organ perfusion
• Swan-guided resuscitation
– C.I. ≥ 4.5, DO2I ≥ 670, VO2I ≥ 166
• Lactic Acid clearance
• Gastric pH

62. Summary
Type PAOP C.O. SVR
HYPOVOLEMIC ↓ ↓ ↑
CARDIOGENIC ↑ ↓ ↑
DISTRIBUTIVE ↓ or N varies ↓
OBSTRUCTIVE ↑ ↓ ↑

63. Vasopressor Agents?
• Augments contractility, after preload
established, thus improving cardiac output.
• Risk tachycardia and increased myocardial
oxygen consumption if used too soon
• Rationale, increased C.I. improves global
perfusion

64. Vasopressors & Inotropic
Agents
• Dopamine
• Dobutamine
• Norepinephrine
• Epinephrine
• Amrinone

65. Dopamine
• Low dose (0.5 - 2 µg/kg/min) = dopaminergic
• Moderate dose (3-10 µg/kg/min) = β-effects
• High dose (> 10 µg/kg/min) = α-effects
• SIDE EFFECTS
– tachycardia
– > 20 µg/kg/min ∆ to norepinephrine

66. Dobutamine
∀ β-agonist
• 5 - 20 µg/kg/min
• potent inotrope, variable chronotrope
• caution in hypotension (inadequate volume)
may precipitate tachycardia or worsen
hypotension

67. Norepinephrine
• Potent α-adrenergic vasopressor
• Some β-adrenergic, inotropic, chronotropic
• Dose 1 - 100 µg/min
• Unproven effect with low-dose dopamine to
protect renal and mesenteric flow.

68. Epinephrine
∀ α- and β-adrenergic effects
• potent inotrope and chronotrope
• dose 1 - 10 µg/min
• increases myocardial oxygen consumption
particularly in coronary heart disease

69. Amrinone
• Phosphodiesterase inhibitor, positive inotropic
and vasodilatory effects
• increased cardiac stroke output without an
increase in cardiac stroke work
• most often added with dobutamine as a second
agent
• load dose = 0.75 -1.5 mg/kg → 5 - 10 µg/kg/min
drip
• main side-effect - thrombocytopenia

70. Dilators
+ inotropes- inotropes
Pressors

71. Summary `pressors & inotropes
- inotrope + inotrope
dilator
pressor
Dobutamine
Milrinone/Amrinone
β-dopamine
Isuprel
Digoxin
Calcium
epinephrine
α-dopamine
neosynephrine
norepinephrine
β-blocker
Labetalol
Ca+2
blocker
ACE inhibitor
hydralazine
nitroglycerine
Nipride

72. Case Studies

73. GSW
• 24 year old male victim of a
shotgun blast to his right lower
quadrant/groin at close range.
• Hemodynamically unstable in the
field and his right lower extremity
was cool and pulseless upon
arrival to the trauma resuscitation
area.

74. Shotgun Blast

75. Post-op
• Patient received 12 L crystalloid, 15
units of blood, 6 units of FFP, and 2 6
packs of platelets.
• HR 130, BP 96/48, T 34.7° C
• PAWP 8, CVP 6, CI 4.2, SVRI 2700,
LVSWI 42.
Diagnosis? Treatment?

76. SHOCK/HYPOVOLEMIA
• FLUIDS… FLUIDS… FLUIDS…
• BLOOD & PRODUCTS TRANSFUSION
• CORRECT
– ACIDOSIS
– COAGULOPATHY
– HYPOTHERMIA

77. MVC
• 38 year old
female restrained
driver who was
involved in a
high speed MVC.
• She sustained a
pulmonary
contusion and
fractured pelvis.

78. ICU Course
• Intubated and monitored with PA-C
• PCWP = 22, CI = 3.5, SVRI = 2400,
LVSWI = 39.8
• HR = 120, BP = 110/56, SpO2 = 91,
UOP = 25 cc/hr
What do you think...

79. HYPOVOLEMIA
ADJUST YOUR WEDGE FOR THE
PEEP

80. Wedge Adjustment
• Measured PAOP - ½ PEEP = “real
PAOP”
• PEEP = 28, therefore “real wedge” = 8

81. Auto-Pedestrian Crash
• Thrown from the
rear bed of pick up
truck during a MVC
at 60 mph.
• Hemodynamically
unstable
• Pain to palpation of
the pelvis
• Hematuria with
Foley®
insertion

84. ICU Course
• Pelvis “closed”
• QID Dressings, intubated, PA-C
inserted
• PCWP = 20, CI = 5.2, SVRI = 280,
LVSWI = 24.5, PEEP = 8
Diagnosis? Treatment?

85. Sepsis
• Fluids
• Correct the cause
• Antibiotics
• Debridement
• Vasopressors
– Phenylephrine
– Levophed

86. Initial Resuscitation
• CVP: 8- 12 mm Hg
• MAP ≥ 65 mm Hg
• UOP ≥ 0.5 cc/kg/hr
• Mixed venous Oxygen Sat ≥ 70%
• Consider:
– Transfusion to Hgb ≥ 10
– Dobutamine up to 20 µg/kg/min

87. Vasopressors
• Assure adequate fluid volume
• Administer via CVL
• Do not use dopamine for renal
protection
• Requires arterial line placement
• Vasopressin:
– Refractory shock
– Infusion rate 0.01 – 0.04 Units/min

88. Steroid Use in Sepsis
• Refractory shock 200-300 mg/day of
hydrocortisone in divided doses for
7 days
• ACTH test
• Once septic shock resolves, taper
dose
• Add fludrocortisone 50 µg po q day

89. Geriatric Trauma
• 70 year old female
• MVC while talking on
her cell phone
• ruptured diaphragm
and spleen s/p OR
• Intubated and PA-C

90. ICU Course
• PCWP = 28, CI = 1.8, SVRI = 3150,
LVSWI = 20.7
Diagnosis? Treatment?

91. Cardiogenic Shock
• Preload augmentation - Consider Fluids
• Contractility
– dopamine
– dobutamine
– phosphodiesterase inhibitor
• Afterload reduction
– nitroglycerin
– dobutamine

92. Don’t forget...
-Samuel D. Gross, 1872
Shock: “rude unhinging of the
machinery of life.”