Division 1 Introduction to Advanced Prehospital Care

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Division 1Introduction to AdvancedPrehospital
Care
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Chapter 4General Principles of
PathophysiologyPart I How Normal Body Processes
Are Altered by Disease and Injury
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Topics

• Disease Risk
• Hypoperfusion
• Shock
• Multiple Organ Dysfunction Syndrome

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Pathophysiology

• The study of how diseases alter the normal
  physiological processes of the human body
• From the root patho meaning disease

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How Cells Respond to Change and Injury
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Cellular Adaptation

• Cells, tissues, organs, and organ systems can
  adapt to both normal and injurious conditions.
• Adaptation to external stressors results in
  alteration of structure and function.
• Examples Growth of the uterus during pregnancy,
  dilation of the left ventricle after an MI.

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Types of Cellular Adaptations(1 of 2)

• Atrophy
• Decreased size resulting from a decreased
  workload
• Hypertrophy
• An increase in cell size resulting from an
  increased workload

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Types of Cellular Adaptations(2 of 2)

• Hyperplasia
• An increase in the number of cells resulting from
  an increased workload
• Metaplasia
• Replacement of one type of cell by another type
  of cell that is not normal for that tissue
• Dysplasia
• A change in cell size, shape, or appearance
  caused by an external stressor

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Cellular Injury

• Hypoxic
• Chemical
• Infectious
• Immunologic/Inflammatory
• Physical agents
• Nutritional balances
• Genetic factors

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Manifestation of Cellular Injury

• When cells are injured metabolism is changed,
  causing substances to infiltrate or accumulate to
  an abnormal degree in cells.

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Cellular Swelling

• Results from a permeable or damaged cellular
  membrane
• Caused by an inability to maintain stable intra-
  and extracellular fluid and electrolyte levels

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Fatty Change

• Lipids invade the area of injury.
• Occurs most commonly in vascular organs, most
  frequently the liver.
• Causes a disruption of the cellular membrane and
  metabolism and interferes with the vital
  functions of the organ.

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Signs and Symptoms of Cellular Change

• Fatigue and malaise
• Altered appetite
• Fever
• Increased heart rate associated with fever
• Pain

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Cell Death (1 of 3)

• Apoptosis
• Injured cell releases enzymes that engulf and
  destroy the cell.
• Cells shrink.
• Eliminating damaged and dead cells allows tissues
  to repair and possibly regenerate.

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Cell Death (2 of 3)

• Necrosis
• A pathological process
• Cells swell and rupture
• Coagulative
• Liquefactive
• Caseous
• Fatty

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Cell Death (3 of 3)

• Gangrenous necrosis
• Cell death over a wide area
• Dry
• Wet
• Gas

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Fluids and Fluid Imbalances
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Water is the most abundant substance in the human
body.
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Where the Water Is Found

• Intracellular fluidfluid inside the cells
• Extracellular fluidall the fluid outside the
  body cells
• Intravascular fluidfluid within the circulatory
  system
• Interstitial fluidfluid outside of the cell
  membranes but not within the circulatory system

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Edema

• Accumulation of water in the interstitial space
  due to disruption in the forces and mechanisms
  that normally keep net filtration at zero

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Mechanisms That Cause Edema

• A decrease in plasma oncotic force
• An increase in hydrostatic pressure
• Increased capillary permeability
• Lymphatic channel obstruction

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Edema (1 of 2)

• Can be local or within a certain organ system
• Sprained ankle vs. pulmonary edema

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Edema (2 of 2)

• Water in interstitial spaces is not available for
  metabolic processes.
• Edema, therefore, can cause a relative condition
  of dehydration.

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Intravenous Therapy
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Blood Components
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The percentage of the blood occupied by the red
blood cells is termed the hematocrit.
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Fluid Replacement
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Transfusion Reactions

• Transfusion reactions occur when there is a
  discrepancy between the blood type of the patient
  and the type of the blood being transfused.

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Signs and Symptoms of Transfusion Reactions

• Fever
• Chills
• Hives
• Hypotension
• Palpitations
• Tachycardia

• Flushing of the skin
• Headache
• Loss ofconsciousness
• Nausea
• Vomiting
• Shortness of breath

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Treatment of Transfusion Reactions (1 of 2)

• IMMEDIATELY stop the transfusion.
• Save the substance being transfused.
• Rapid IV infusion.

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Treatment of Transfusion Reactions (2 of 2)

• Assess the patients mental status.
• Administer oxygen.
• Contact medical direction.
• Be prepared to administer mannitol,
  diphenhydramine, or furosemide.

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Intravenous Fluids
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Hemoglobin-Based Oxygen-Carrying Solutions
(HBOCs)  

• Commonly referred to as blood substitutes
• Compatible with all blood types
• Do not require blood typing, testing, or
  cross-matching
• PolyHeme
• Hemopure

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Colloids

• Colloids remain in intravascular spaces for an
  extended period of time and have oncotic force.
• Plasma protein fraction (Plasmanate)
• Salt-poor albumin
• Dextran
• Hetastarch (Hespan)

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Crystalloids

• Crystalloid solutions are the primary compounds
  used in prehospital care.
• Isotonic solutions
• Hypertonic solutions
• Hypotonic solutions

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The effects of hypertonic, isotonic, and
hypotonic solutions on red blood cells
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Most Commonly Used Solutions in Prehospital Care
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Acid-Base Derangements
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Respiratory Acidosis

• Caused by abnormal retention of CO2 from
  impaired ventilation due to problems occurring in
  the lungs or respiratory center of the brain.
  

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Respiratory Alkalosis
Caused by increased respiration and excessive
elimination of CO2. The CO2 level is decreased
and the pH is increased.
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Metabolic Acidosis
Results from the production of metabolic acids
such as lactic acid. These acids consume
bicarbonate ions. Can be the result of
dehydration, diabetes, or medication usage.
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Compensation for metabolic acidosis begins with
an increase in respirations.
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Metabolic Alkalosis

• The pH is increased and the CO2 level is normal.
  It is usually caused by administration of
  diuretics, loss of chloride ions associated with
  prolonged vomiting, and overzealous
  administration of sodium bicarbonate.

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Genetics and Other Causes of Disease
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Many Factors Combine to Cause Disease (1 of 3)

• Genetics
• Environment
• Lifestyle
• Age
• Gender

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Many Factors Combine to Cause Disease (2 of 3)

• Inherited traits are determined by molecules of
  deoxyribonucleic acid (DNA).
• Each somatic cell contains 46 chromosomes.
• Sex cells contain 23 chromosomes.

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Many Factors Combine to Cause Disease (3 of 3)

• An offspring receives 23 chromosomes from the
  mother and 23 chromosomes from the father.
• One or more chromosomes may be abnormal and may
  cause a congenital disease or a propensity toward
  acquiring a disease later in life.

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• Most disease processes are multifactorial in
  origin.

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Disease Effects on Individuals

• Host
• Agent
• Environment

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Disease Effects on Populations

• Incidence
• Prevalence
• Mortality

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Family History and Associated Risk Factors
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Immunologic Disorders

• A number of immunologic disorders are more
  prevalent among those with a family history of
  the disorder.

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Cancer

• Some types of cancer tend to cluster in families
  and seem to have a combination of genetic and
  environmental causes.
• Breast cancer
• Colorectal cancer

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Endocrine Disorders

• The most common endocrine disorder is diabetes
  mellitus.
• Leading cause of
• Blindness
• Heart disease
• Kidney failure
• Premature death
• Both Type I and Type II diabetes can be family
  related.

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Hematological Disorders

• There are many causes of hereditary hematological
  disorders such as gene alteration and
  histocompatibility (tissue interaction)
  dysfunctions.
• Hemophilia
• Hemochromatosis

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Cardiovascular Disorders

• The cardiovascular system can be greatly affected
  by genetic disorders.
• Elongation of the QT interval
• Mitral valve prolapse
• Coronary artery disease
• Hypertension
• Cardiomyopathy

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Renal Disorders

• Caused by a variety of factors, primarily
  hypertension.
• EMS is increasingly being called upon to deal
  with complications of dialysis including
• Problems with vascular access devices
• Localized infection and sepsis
• Electrolyte imbalances

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Rheumatic Disorders

• Gout is a disorder both genetic and environmental
  characterized by the deposit of crystals in the
  joints, most commonly the great toe.
• The crystals form as a result of abnormally high
  levels of uric acid in the blood.

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Gastrointestinal Disorders

• Lactose intolerance
• Crohns disease
• Peptic ulcers
• Cholecystitis
• Obesity

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Neuromuscular Disorders

• Diseases of the nervous and muscular systems
  include
• Huntingtons disease
• Multiple sclerosis
• Alzheimers disease

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Psychiatric Disorders

• Genetic and biological causes of these disorders
  are being studied and increasingly understood.
• Schizophrenia
• Manic-depressive illness (bipolar disorder)

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Hypoperfusion
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• Hypoperfusion (shock) is inadequate perfusion of
  body tissues.

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Progression of Shock
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The Pathophysiology of Hypoperfusion
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Causes of Hypoperfusion (1 of 3)

• Inadequate pump
• Inadequate preload
• Inadequate cardiac contractile strength
• Excessive afterload

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Causes of Hypoperfusion (2 of 3)

• Inadequate fluid
• Hypovolemia

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Causes of Hypoperfusion (3 of 3)

• Inadequate container
• Dilated container without change in fluid volume
  (inadequate systemic vascular resistance)
• Leak in the container

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Shock at the Cellular Level

• Shock causes vary however, the ultimate outcome
  is impairment of cellular metabolism.

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Impaired Use of Oxygen

• When cells dont receive enough oxygen or cannot
  use it effectively, they change from aerobic to
  anaerobic metabolism.

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Glucose Breakdown (1 of 2)

• Stage one, glycolysis, is anaerobic (does not
  require oxygen). It yields pyruvic acid, with
  toxic by-products such as lactic acid, and very
  little energy.

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Glucose Breakdown (2 of 2)

• Stage two is aerobic (requires oxygen). In a
  process called the Krebs or citric acid cycle,
  pyruvic acid is degraded into carbon dioxide and
  water, which produces a much higher yield of
  energy.

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Compensation and Decompensation

• Usually the body is able to compensate for any
  changes. However, when the various compensatory
  mechanisms fail, shock develops and may progress.

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Compensation Mechanisms

• The catecholamines epinephrine and norepinephrine
  may be secreted.
• The renin-angiotensin system aids in maintaining
  blood pressure.
• Another endocrine response by the pituitary gland
  results in the secretion of anti-diuretic hormone
  (ADH).

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Shock Variations (1 of 3)

• Compensated shock is the early stage of shock
  during which the bodys compensatory mechanisms
  are able to maintain normal perfusion.

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Shock Variations (2 of 3)

• Decompensated shock is an advanced stage of shock
  that occurs when the bodys compensatory
  mechanisms no longer maintain normal perfusion.

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Shock Variations (3 of 3)

• Irreversible shock is shock that has progressed
  so far that the body and medical intervention
  cannot correct it.

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Types of Shock

• Cardiogenic
• Hypovolemic
• Neurogenic
• Anaphylactic
• Septic

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Cardiogenic Shock

• The heart loses its ability to supply all body
  parts with blood.
• Usually the result of left ventricular failure
  secondary to acute myocardial infarction or CHF.
• Many patients will have normal blood pressures.

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Cardiogenic Shock Evaluation

• The major difference between cardiogenic shock
  and other types of shock is the presence of
  pulmonary edema causing
• Difficulty breathing.
• As fluid levels rise, wheezes or crackles (rales)
  may be heard.
• There may be a productive cough with white or
  pink-tinged foamy sputum.
• Cyanosis, altered mentation, and oliguria.

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Cardiogenic Shock Treatment (1 of 2)

• Assure an open airway.
• Administer oxygen.
• Assist ventilations as necessary.
• Keep the patient warm.

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Cardiogenic Shock Treatment (2 of 2)

• Elevate the patients head and shoulders.
• Establish IV access with minimal fluid
  administration.
• Monitor the heart rate.
• Dopamine or dobutamine may be administered.

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Hypovolemic Shock

• Shock due to loss of intravascular fluid
• Internal or external hemorrhage
• Trauma
• Long bones or open fractures
• Dehydration
• Plasma loss from burns
• Excessive sweating
• Diabetic ketoacidosis with resultant osmotic
  diuresis

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Hypovolemic Shock Evaluation (1 of 2)

• Altered level of consciousness.
• Pale, cool, clammy skin.
• Blood pressure may be normal, then fall.

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Hypovolemic Shock Evaluation (2 of 2)

• Pulse may be normal then become rapid, finally
  slowing and disappearing.
• Urination decreases.
• Cardiac dysrhythmias may occur.

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Hypovolemic Shock Treatment

• Airway control.
• Control severe bleeding.
• Keep the patient warm.
• Administer a bolus of crystalloid solution for
  fluid replacement.
• Non-trauma or no blood loss
• Bolus crystalloid or colloid solutions
• Trauma or blood loss
• Permissive hypotension SBP of 70-85 mmHg
• PASG if part of local protocol.

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Neurogenic Shock

• Results from injury to brain or spinal cord
  causing an interruption of nerve impulses to the
  arteries.
• The arteries dilate causing relative hypovolemia.
• Sympathetic impulses to the adrenal glands are
  lost, preventing the release of catecholamines
  with their compensatory effects.

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Neurogenic Shock Evaluation

• Warm, dry, red skin
• Low blood pressure
• Slow pulse

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Neurogenic Shock Treatment

• Airway control.
• Maintain body temperature.
• Immobilization of patient.
• Consider other possible causes of shock.
• IV access and medications that increase
  peripheral vascular resistance.

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Anaphylactic Shock

• A severe immune response to a foreign substance.
• Signs and symptoms most often occur within a
  minute, but can take up to an hour.
• The most rapid reactions are in response to
  injected substances
• Penicillin injections
• Bees, wasps, hornets

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Anaphylactic Shock Evaluation

• Cardiovascular system
• Vasodilation, increased heart rate, decreased
  blood pressure
• Gastrointestinal system
• Nausea, vomiting, abdominal cramping, diarrhea
• Nervous system
• Altered mental status, dizziness, headache,
  seizures, tearing

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Anaphylactic Shock Treatment

• Airway protection may includeendotracheal
  intubation.
• Establish an IV of crystalloidsolution.
• Pharmacological intervention
• Epinephrine, antihistamines, corticosteroids,
  vasopressors, inhaled beta agonists

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Septic Shock

• An infection that enters the bloodstream and is
  carried throughout the body.
• The toxins released overcome the compensatory
  mechanisms.
• Can cause the dysfunction of an organ system or
  result in multiple organ dysfunction syndrome.

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Septic Shock Evaluation

• The signs and symptoms are progressive.
• Increased to low blood pressure
• High fever, no fever, or hypothermic
• Skin flushed, pale, or cyanotic
• Difficulty breathing and altered lung sounds
• Altered mental status

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Septic Shock Treatment

• Airway control.
• IV of crystalloid solution.
• Dopamine to support blood pressure.
• Monitor heart rhythm.

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Multiple Organ Dysfunction Syndrome

• MODS is the progressive impairment of two or more
  organ systems from an uncontrolled inflammatory
  response to a severe illness or injury.

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MODS Stages
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Primary MODS

• Organ damage results directly from a specific
  cause such as ischemia or inadequate tissue
  perfusion from shock, trauma, or major surgery.
• Stress and inflammatory responses may be mild and
  undetectable.
• During this response, neutrophils, macrophages,
  and mast cells are thought to be primed by
  cytokines.

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Secondary MODS

• The next time there is an injury, ischemia, or
  infection, the primed cells are activated,
  producing an exaggerated inflammatory response.
• The inflammatory response enters a
  self-perpetuating cycle causing damage and
  vasodilation.
• An exaggerated neuroendocrine response is
  triggered causing further damage.

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MODS 24 Hours after Resuscitation

• Low grade fever
• Tachycardia
• Dyspnea
• Altered mental status
• General hypermetabolic, hyperdynamic state

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MODS within 24 to 72 Hours

• Pulmonary failure begins.

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MODS within 7 to 10 Days

• Hepatic failure begins.
• Intestinal failure begins.
• Renal failure begins.

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MODS within 14 to 21 Days

• Renal and hepatic failure intensify.
• Gastrointestinal collapse.
• Immune system collapse.

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MODS after 21 Days

• Hematological failure begins.
• Myocardial failure begins.
• Altered mental status resulting from
  encephalopathy.
• Death.

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Summary

• Disease Risk
• Hypoperfusion
• Shock
• Multiple Organ Dysfunction Syndrome