Pharmacotherapy of Shock.ppt

8/10/2019 Pharmacotherapy of Shock.ppt

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Pharmacotherapy

of Shock


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Introduction

Review the current view on

etiology, pathophysiology and

management of shock withemphasis on pharmacotherapy.

Daniel Game, M.D.

O. D. Polk, Jr., M.D.

Wayne Davis, M.D.


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Topics of Discussion

Pathophysiology of Shock

Types of Circulatory Shock

Management of Shock Inotropic Agents

Vasodilators


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Shock

Term choc French for push or

impact was first published in 1743

by the physician LeDran Beliefsymptoms arose from fear

or some other form of altered

cerebral function

Crile in 1899 showed that

replacement of blood volume

decreased mortality experimentally


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Determinants of Shock

Inadequate tissue perfusion

Sustained loss of effective circulatory

blood volume

Breakdown of cellular metabolism and

microcirculatory homeostasis

Hypoperfusion of peripheral tissue

that leads to a diminutive

transcapillary exchange function

Disproportion between VO2and DO2


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Hemodynamic States of

Shock Hyperdynamic State

Hypodynamic State

Related to: Cardiac Output (CO)

Systemic Vascular Resistance

(SVR)


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Pathophysiology of

Shock Shock develops with inadequate

capillary perfusion by decreased

Cardiac Output following heartattack (cardiogenic shock) or

blood/volume loss (hypovolemic

shock)


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Mediators of Shock

Toxins

Endotoxins

Oligo- and polypeptides

Complement Factors

Opiods

TNF, Interleukins

Fatty Acid Derivatives

Arachidonic acid metabolites Varia

Calcium


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Main Classes of Shock

Hypovolemic Shock

Distributive Shock Cardiogenic Shock

Obstructive Shock


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Hypovolemic Shock

Hemorrhagic/Traumatic

Dehydrative Burn


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Distributive Shock

Septic

Anaphylactic/

Anaphylactoid

Neurogenic


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Obstructive Shock

Pulmonary Embolism

Cardiac Tamponade

Pneumothorax


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Question

Which one of the folowing is the most common cause of severe

Lactic acidosis (blood lactate concentration >5 mmol/L)?

a. Ethanol intoxicationb. Severe liver disease

c. Circulatory shock

d. Ischemic bowel

e. Acute asthma


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Management of Shock

Shock begins when DO2 to the

cells is inadequate to meet

metabolic demand The major therapeutic goals in

shock therefore are sufficient

tissue perfusion and oxygenation

Early diagnosis remains a major

problem


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Pulmonary Artery

Catheter WaveformsRight Atrium Right Ventricle Pulmonary Artery PCWP


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Hemodynamic Characteristics inDifferent Types of Shock

Type Preload CO PVR SVR

Hemmorrhagic

Anaphylactic

Cardiogenic

Septic(Hyperdynamic)

Septic

(Hypodynamic)

/


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QuestionThe wavefrom shown in this figure was observed while

attempting to advance a pulmonary arterial catheter, with the

Balloon inflated, from the proximal pulmonatry artery to a

wedged position.

Wh

i

c

h

Which one of the following best explains the terminal

portion of the depicted waveform?

a. Pulmonary hypertensionb. Mitral regurgitation

c. Severe left ventricular dysfunction

d. Obstruction of the catheter tip

e. Pericardial tamponade


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Inotropic Agents and

Vasodilators Vasoactive drugs are an important

pharmacologic defense in the

treatment of shock.

May be required to support BP in the

early stages of shock.

These agents may be needed to:

Enhance CO through the use of inotropic

agents

Increase SVR through the use of

vasopressors


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Effects of Inotropic

Agents and VasodilatorsEpinephrine a1,b1, (b2) 0.020.5

Norepinephrine a1, b1 0 - 0.05

0.5Dopamine b2,DR, (a) 2 -12

Dobutamine b1, b2 2 - 12

Dopexamine b1, b2, DR 0 - 0.9 - 5

Vasopressin Angiotensin III 5 - 20

Amrinone PDI 5 -10

Drug Receptor CO SVR Dose Range

0 -

(mg/kg/min)

1


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Effects of Inotropic

Agents and Vasodilators

Nifedipine 0 - 0.5 - 10

Nitroglycerin 0 - 3 - 5

Nitroprusside 0 - 0.5 - 5

Prostacyclin 10 - 40

2

Drug CO SVR Dose Range

(mg/kg/min)


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DopamineAn endogenous precursor of norepinephrine with

multiple dose-related effects

Low Dose (0.5 - 3 mg/kg/min)

b2and dopaminergic (DR) effects

Enhanced blood flow to renal andsplanchnic beds

Moderate Dose (5 -10 mg/kg/min)

Positive inotropic effects

High Dose (>20 mg/kg/min)

a-actions (vasoconstriction)


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Question


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Reference

Pharmacotherapy of Shock. In: The Pharmacologic

Approach to the Critically Ill Patient, 3rded. Williams& Wilkins,1994, pp 11041121.

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Pharmacotherapy of Shock.ppt