Acute Respiratory Distress Syndrome, Fat Embolism,

1
Acute Respiratory Distress Syndrome, Fat
Embolism, Thromboembolic Disease in the
Orthopaedic Trauma Patient
Steve Morgan, MD Scott Adams, MD Original
Authors Steve Morgan, MD March 2004 New
Authors Steve Morgan, MD Scott Adams, MD
Revised January 2007
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Objectives

• Define
• ARDS
• FES
• Thromboembolic Disease
• Understand Etiology Physiology of each Condition

• Understand
• Prevention
• Diagnosis
• Treatment
• Outcomes

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ARDS Acute Respiratory Distress Syndrome

• Acute respiratory failure in the post traumatic
  period characterized by a decreased PaO2 and a
  diffuse and often massive extravasations of fluid
  from the pulmonary vasculature to the
  interstitial space of the lungs.

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ARDS Clinical Definition

• Acute onset of symptoms
• Ratio of PaO2 to FIO2 of 200 mm Hg or less
• Bilateral infiltrates on CXRs
• Pulmonary arterial wedge pressure of 18 mm Hg or
  less or no clinical signs of left atrial
  hypertension
• American-European Consensus Conference (AECC) on
  ARDS, 94

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ARDS

• Incidence 5 8 after polytrauma
• Much lower in isolated fracture
• Mortality up to 40
• Uncommon in Children and the Elderly

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ARDSCommon Causes

• Trauma
• Massive Transfusion
• Embolism
• Sepsis
• Aspiration
• Abdominal Distension

• Pulmonary Edema
• Prolonged LOC
• Cardiopulmonary Bypass
• Pancreatitis
• Major Burns

MULTIFACTORAL
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ARDS Etiology

• ARDS related to MODS
• Release of inflammatory mediators results in
  organ dysfunction

Inflammatory Mediators
Organ Injury
Trauma
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ARDS PATHOPHYSIOLOGY

• Systemic Inflammatory Mediators
• Damage to Endothelial Lining
• Increased Capillary Permeability
• Fluid Extravasation

• Alveolar Collapse
• Decreased Pulmonary Compliance
• Ventilation Perfusion Abnormalities
• Arteriolar Hypoxemia

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ARDS
Chest Radiograph
Autopsy Specimen
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ARDS Chest CT Scan
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ARDSPrevention

• Limiting Blood Loss
• Decreasing Transfusion Requirements
• Early Stabilization Of Unstable Fractures
• Early Prophylactic Mechanical Ventilation

Temporary Ex-Fix For Stabilization
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ARDS Treatment

• Ventilator Support
• Acceptable ABGs
• Avoid further alveolar damage
• Toxic FIO2
• Barotrauma
• General Organ Support
• Research
• Optimal ventilator settings
• Pharmalogical agents

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ARDSOutcome

• Significant Cause of Mortality
• Major Cause of Death in Patients with the Lowest
  ISS scores
• 30 - 40 Mortality Rate
• Mortality Rate Slowly Decreasing with Changing
  Improving Therapy

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Fat Embolism Syndrome(FES)

• A condition characterized by hypoxia, confusion
  and petechiae presenting soon after long bone
  fracture and soft tissue injury.
• Diagnosis of Exclusion

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FES

• Often Placed in the Category of ARDS
• May share common pathological pathways
• R/O other Causes of Hypoxia Confusion
• Index Patient
• young adult with isolated LE injury seen after
  long transfer with no supporting therapy or
  splintage.

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FES

• Occurs in 0.9 8.5 of all fracture patients
• Up to 35 of the multiply injured
• Mortality 2.5
• Rare in upper limb injury and children

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Etiology

• The likely pathogenetic reaction of lung tissue
  to shock, hypercoagulability and lipid metabolism
• Mechanical Theory
• Biochemical Theory

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Mechanical Theory

• Fracture Liberates Fat
• Intravasation - Fat Enters Venous System
• Fat Causes Mechanical Obstruction

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Mechanical Theory
FES To Brain On MRI

• Systemic Fat Embolization
• Patent Foramen Ovale
• Pulmonary Pre-Capillary Shunts
• Skin petechiae, CNS signs

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Biochemical Theory

• Neutral Fat and Chemical Mediators Released at
  Time of Fracture
• Neutral Fat Metabolized by Lipases releases Free
  Fatty Acids
• Free Fatty Acids Result in Endothelial Lung
  Damage

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FES Diagnosis

• Major Criteria
• Hypoxemia
• CNS Depression
• Petechial Rash
• Pulmonary Edema

• Minor Criteria
• Tachycardia
• Pyrexia
• Retinal Emboli
• Fat in Urine
• Fat in Sputum
• Thrombocytopenia
• Decreased Hematocrit

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FES Diagnosis

• Gurd Wilson Criteria
• At least 1 Major Sign
• 4 Minor Signs

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FES Prevention

• Appropriate Splinting
• Early Fracture Stabilization
• Oxygen Therapy

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FES Prevention

• Therapies
• Fluid Loading
• Hypertonic Fluid
• Alcohol
• Heparin
• Dextran
• Aspirin
• None Shown to be Effective

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FES Treatment

• Supportive
• Oxygen Therapy to maintain PaO2
• Mechanical Ventilation
• Adequate Hydration

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FES Treatment Steroids

• Steroids
• Decrease endothelial damage
• 30mg/kg initial dose repeated _at_ 4 Hours, 1gm dose
  repeated _at_ 8 Hours Total 3 Doses
• Complications - Frequent
• Infection
• GI
• Steroid Therapy Avoided Secondary To Poor Risk
  Benefit Ratio

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Systemic Effects of Trauma
Second Hit in susceptible patients
24 hours
48 hours
Injury (First Hit)
IM Nailing as a Cause of Secondary Systemic Injury
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Fracture Fixation Technique-Controversial-

• Early Total Care
• Definitive Early Fixation
• Nail or Plate

• Damage Control
• Temporary Stability
• External Fixator
• Limit Further Blood Loss
• Limit Anesthetic Time
• Delay Definitive Fracture fixation

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Effect of IM Nailing

• Increased IM Pressure
• Embolic Showers On Echocardiograms
• Caused by
• Canal Opening
• Reaming
• Nail Insertion (both reamed unreamed)

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Fracture Fixation Technique-Controversial-

• IM Nail - Reamed vs Un-Reamed
• Decreased with Unreamed Technique
• Pape et al
• No Difference
• Keating et al
• Canadian OTS
• IM Nail Reamed vs Plate Osteosynthesis
• No Difference In Pulmonary Dysfunction
• Bosse et al

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DVT Incidence

• DVT occurrence 60 if ISS gt9.
• 35-60 DVT in pelvic fracture
• PE-Most common preventable cause of death in
  trauma.

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Virchow Triad
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Hypercoaguability

• Tissue Thromboplastin
• Activated Procoagulants
• Decreased Fibrinolytic Activity
• Ineffective Heparin Clearance of Activated
  Clotting Factors
• Catecholamine Release

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Endothelial Injury

• Direct Trauma to Vein at time of Injury
• Compression of the Vein Secondary to Fracture
  Position
• Vein Manipulation at Time of Fracture Fixation

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Venous Stasis

• Immobilization
• Hypotension
• Venous Occlusion
• Edema
• Fracture Position
• Tourniquet

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DVT Prevention

• Goals
• Clinically significant events
• PE
• Post Thrombotic syndrome
• Low Complication Rate
• High Compliance Rate
• Cost Effective

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DVT Prevention
Mechanical Non Pharamcologic
Pneumatic Compression
Elastic Stockings
Vena Cava Filter
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DVT Prevention
Pharamcologic
Pentasacharides
Unfractionated Heparin
Elastic Stockings
LMWH Heparin
Warfarin Oral Anticoagulants
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Prophylaxis

• Elastic Stockings
• Mechanical Compression Devices
• Early Mobilization
• IVC Filter (PE Prophylaxis)

• Pentasaccharide
• Low Molecular Weight Heparin
• Heparin
• Aspirin
• Warfarin

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Mechanical Methods

• Activity
• Compression Stockings
• Sequential Compression Device
• Pedal Pumps
• Mechanism of Action
• Decrease Stasis
• ? Fibrinolytic Activity

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IVC Filter Indications

• Anticoagulation Prohibited
• High Risk Patients
• DVT Prior to Necessary Surgery
• PE Despite Anticoagulation

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IVC Filter
Advantages
Disadvantage

• Prevents Major PE
• Low Morbidity
• 96 Patent
• 8 Migration
• 4 PE
• Filter insertion in the ICU

• Expensive
• Invasive
• Does not treat DVT
• Venous Insufficiency
• Filter Occlusion

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Pentsaccharide

• Selective Inhibitor of Activated Xa
• Decreased DVT rate with no change in major
  bleeding rate compared to LMWH
• Eriksson B I et al N Engl J Med 2001
• Increased risk of minor bleeding
• Delay administration for several hours after
  surgery and removal of epidural catheter

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Low Molecular Weight Heparin(LMWH)

• Potentiates Antithrombin III
• Inhibits Factor Xa II
• Minimal effects on other Factors

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LMWH
Advantages
Disadvantage

• No Monitoring
• Increased Efficacy
• Longer 1/2 life
• Predictable Response
• Lower risk of thrombocytopenia

• Parenteral Administration
• Cost

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Heparin

• Heparin Potentiates Anti-Thrombin III Activity
• Complex Inhibits
• Thrombin (IIa), IXa, Xa
• Heparin effect relative short duration
• Reversed with Protamine Sulfate
• Significant hemorrhage risk

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SQ Heparin
Advantages
Disadvantage

• Low Cost
• No Monitoring
• Convenient
• Relatively Low Incidence of Bleeding

• Insufficient Efficacy in High Risk Patients
• Unpredictable Responses
• Heparin Induced Thrombocytopenia

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Aspirin

• Inhibits cyclooxygenase
• Decreases Platelet Adherence
• ? Effectiveness in Musculoskeletal Trauma
• Venous clots not typically found to have Platelet
  aggregates

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Aspirin
Advantages
Disadvantage

• Oral Administration
• Tolerated well
• In-expensive
• No Monitoring

• ? Efficacy when used alone
• GI Intolerance
• Prolonged anti-platelet effect

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Warfarin

• Blocks Vit K conversion in Liver
• Effects Vit K Dependent Factors
• Effects the Extrinsic Clotting System
• Factor VII Effected first, Short Half Life
• Monitored with Pro-Time
• INR 2.0-2.5
• Reversed With Vitamin K or FFP

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Warfarin
Advantages
Disadvantage

• Effective
• Oral Administration
• Inexpensive

• Requires Monitoring
• Difficult to Reverse
• Increased Bleeding Complications in Elderly

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EAST Guidelines

• Guidelines based on qualitative review of the
  current scientific literature improve uniformity
  of opinion and prescribing practices
• Watts JBJS B 05

• Risk Factors
• Level I Evidence Major Significance
• Spinal Fracture
• Spinal Cord Injury
• Level II No Major Significance
• Advanced Age
• ISS Score
• Blood Transfusion
• Long Bone, Pelvis, Head Injury

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DVT screening

• Physical Exam
• Ascending venography
• Duplex Ultrasonography
• Magnetic Resonance Venography

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Physical Examination

• Calf Swelling
• Palpable Venous Cords
• Calf Pain
• Homans Sign
• All Unreliable

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Ascending Contrast Venography

• Sensitive for detection
• Invasive
• Dye Problems (allergies, renal)
• Injection Site Irritation
• Poor Pelvic Vein Evaluation
• Gold Standard

Invasiveness,expense make ACV a poor screening
tool
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Doppler/Duplex Ultrasound

• Comparable to Venogram
• Non Invasive
• No Morbidity
• Poor Axial (i.e Pelvic) Vein Evaluation
• Operator Dependent
• Good Screening Tool
• Noninvasive, reproducible

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Magnetic Resonance Venography

• Non Invasive
• Good Visualization of Pelvic Veins
• Difficult in Polytrauma Patient
• Excellent specificity and sensitivity for
  suspected DVT
• Controversial for screening

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Pulmonary Embolism

• Clinical
• Shortness of breath, agitation, confusion
• Laboratory
• ? PaO2, ? A-a gradient
• Diagnostic studies
• V/Q scans
• Pulmonary Angiogram, CT PA

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Ventilation Perfusion Scan

• Ventilation Perfusion mismatch
• Results
• Low probabiltity
• 15 False Negative
• Medium
• Need Angiogram
• High probability
• 15 False Positive
• Screening Tool

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Pulmonary Angiogram

• Angiographic Evaluation of pulmonary vascular
  tree
• Allows Placement of IVC Filter in same setting if
  indicated
• Sensitive - Standard in PE Detection. Diagnostic

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Treatment PE

• Anticoagulation
• Filter for recurrent event despite
  anticoagulation
• Thrombectomy
• Serious Acute PE
• Patient in extremous
• Large identifiable PE

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Treatment DVT/PE

• LMWH / Pentasaccharide
• Mass related dose SQ inj
• Single daily dose
• No monitoring necessary
• Discontinue when Therapeutic on Warfarin

• Heparin
• Bolus 10-15K units
• Continuous Infusion
• 1000Units/Hr
• Goal ? PTT 2x Control
• Prevent Clot propagation and recurrent PE
• Discontinue when Therapeutic on Warfarin

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Treatment DVT/PE

• Warfarin
• INR 2.0-3.0
• 3-6 Month Duration
• Contraindicated in
• Pregnancy
• Liver insufficiency
• Poor Compliance
• Prolonged Therapy may decrease recurrence rates

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DVT/PE Outcome

• No Diagnosis and Treatment
• 30 Mortality
• Correct Diagnosis and Therapy
• 11 Mortality in First Hour
• 8 Mortality After First Hour

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DVT/PE Outcome

• Post Thrombotic Syndrome
• Valvular Incompetence
• Venous Stasis
• Edema
• Cutaneous Atrophy
• Recurrent DVT
• 20 of Patients

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