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 and November 2011

Objectives

• Define– ARDS

– FES

– Thromboembolic Disease

• Understand Etiology & Physiology of each Condition

• Understand– Prevention

– Diagnosis

– Treatment

– Outcomes

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.

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

ARDS

• Incidence 5% – 8% after polytrauma– Much lower in isolated fracture

• Mortality up to 40%

• Uncommon in Children and the Elderly

ARDSCommon Causes

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

• Pulmonary Edema• Prolonged LOC• Cardiopulmonary

Bypass• Pancreatitis• Major Burns

MULTIFACTORAL

ARDS Etiology

• ARDS related to MODS

• Release of inflammatory mediators results in organ dysfunction

Trauma InflammatoryMediators

OrganInjury

ARDS PATHOPHYSIOLOGY

• Systemic Inflammatory Mediators

• Damage to Endothelial Lining

• Increased Capillary Permeability

• Fluid Extravasation

• Alveolar Collapse • Decreased Pulmonary

Compliance• Ventilation Perfusion

Abnormalities• Arteriolar Hypoxemia

ARDS

Chest Radiograph Autopsy Specimen

ARDS Chest CT Scan

ARDSPrevention

• Limiting Blood Loss

• Decreasing Transfusion Requirements

• Early Stabilization Of Unstable Fractures

• Early Prophylactic Mechanical Ventilation

Temporary Ex-Fix For Stabilization

ARDS Treatment

• Ventilator Support – Acceptable ABG’s– Avoid further alveolar damage

• Toxic FIO2

• Barotrauma

• General Organ Support• Research

– Optimal ventilator settings– Pharmalogical agents

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

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

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.

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

Etiology

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

• Mechanical Theory

• Biochemical Theory

Mechanical Theory

• Fracture Liberates Fat

• Intravasation - Fat Enters Venous System

• Fat Causes Mechanical Obstruction

Mechanical Theory

• Systemic Fat Embolization

– Patent Foramen Ovale

– Pulmonary Pre-Capillary Shunts

– Skin petechiae, CNS signs

FES To Brain On MRI

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

Gurd et al

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

Gurd et al

FES Diagnosis

• Gurd & Wilson Criteria

• At least 1 Major Sign

• 4 Minor Signs

FES Prevention

• Appropriate Splinting

• Early Fracture Stabilization

• Oxygen Therapy

FES Prevention

• Therapies– Fluid Loading

– Hypertonic Fluid

– Alcohol

– Heparin

– Dextran

– Aspirin

• None Shown to be Effective

FES Treatment

• Supportive

– Oxygen Therapy to maintain PaO2

– Mechanical Ventilation

– Adequate Hydration

FES Treatment Steroids• Steroids

– Decrease endothelial damage– 30mg/kg initial dose repeated @ 4 Hours, 1gm

dose repeated @ 8 Hours: Total 3 Doses

• Complications - Frequent– Infection– GI

• Steroid Therapy Avoided Secondary To Poor Risk Benefit Ratio

Systemic Effects of Trauma

Injury (First Hit)

24 hours 48 hours

Post InjuryInflammatoryResponse in2 Patients

Second Hit in susceptible patients

ARDSMODSThreshold

IM Nailing as a Cause of Secondary Systemic Injury

• 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

Fracture Fixation Technique-Controversial-

Effect of IM Nailing

• Increased IM Pressure

• Embolic Showers On Echocardiograms

• Caused by– Canal Opening– Reaming – Nail Insertion (both reamed & unreamed)

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

DVT Incidence

• DVT occurrence 60% if ISS >9.

• 35%-60% DVT in pelvic fracture

• PE-Most common preventable cause of death in trauma.

Virchow Triad

Hypercoaguability

• Tissue Thromboplastin

• Activated Procoagulants

• Decreased Fibrinolytic Activity

• Ineffective Heparin Clearance of Activated Clotting Factors

• Catecholamine Release

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

Venous Stasis

• Immobilization

• Hypotension

• Venous Occlusion – Edema– Fracture Position

• Tourniquet

DVT Prevention

Goals

• Clinically significant events– PE– Post Thrombotic syndrome

• Low Complication Rate• High Compliance Rate• Cost Effective

MechanicalNon Pharamcologic

DVT Prevention

PneumaticCompression

Vena CavaFilter

ElasticStockings

Pharamcologic

DVT Prevention

UnfractionatedHeparin

LMWH Heparin

ElasticStockingsWarfarin

OralAnticoagulants

Pentasacharides

Prophylaxis

• Elastic Stockings

• Mechanical Compression Devices

• Early Mobilization

• IVC Filter (PE Prophylaxis)

• Pentasaccharide

• Low Molecular Weight Heparin

• Heparin

• Aspirin

• Warfarin

Mechanical Methods

• Activity• Compression

Stockings• Sequential

Compression Device• Pedal PumpsMechanism of Action• Decrease Stasis Fibrinolytic Activity

IVC Filter Indications

• Anticoagulation Prohibited

• High Risk Patients

• DVT Prior to Necessary Surgery

• PE Despite Anticoagulation

IVC Filter

• 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

Advantages Disadvantage

• No Recommendation for Vena Caval Filter

ACCP Recommendation on Vena Cava Filter

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

Low Molecular Weight Heparin(LMWH)

• Potentiates Antithrombin III

• Inhibits Factor Xa & II

• Minimal effects on other Factors

LMWH

• No Monitoring

• Increased Efficacy

• Longer 1/2 life

• Predictable Response

• Lower risk of thrombocytopenia

• Parenteral Administration

• Cost

Advantages Disadvantage

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

SQ Heparin

• Low Cost

• No Monitoring

• Convenient

• Relatively Low Incidence of Bleeding

• Insufficient Efficacy in High Risk Patients

• Unpredictable Responses

• Heparin Induced Thrombocytopenia

Advantages Disadvantage

Aspirin

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

• ? Efficacy when used alone

• GI Intolerance• Prolonged anti-platelet

effect

Advantages Disadvantage

Aspirin

• Inhibits cyclooxygenase

• Decreases Platelet Adherence

• ? Effectiveness in Musculoskeletal Trauma– Venous clots not typically found to have

Platelet aggregates

• No Recommendation For The Use of Aspirin

• Recommend Against The Use of Aspirin For Any Indication

ACCP Recommendation on Aspirin

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

Warfarin

• Effective• Oral Administration• Inexpensive

• Requires Monitoring• Difficult to Reverse• Increased Bleeding

Complications in Elderly

Advantages Disadvantage

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

ACCP 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 Cord Injury– Major Trauma– Hip Fractures– Complex Lower-extremity

Fracture– Pelvic Fracture– Prolonged Immobility– Delay in Commencement Of

Thromboprophylaxis

• Recommend Routine Thromboprophylaxis

• Fondaparinux• LMWH• Warfarin (INR 2.5)• LDUH

ACCP Guidelines on Hip Fractures

• Recommend Routine Thromboprophylaxis

• LMWH Once Hemostasis Obtained

• IPC and/or GCS– While Obtaining

Hemostasis

ACCP Guidelines on Spinal Cord Injury

• No Routine Thromboprophylaxis

ACCP Guidelines on Isolated Injuries Distal To The Knee

Duration of Prophylaxis

• 10 to 35 Days

• Agents– LMWH

– Fondaparinux

– Warfarin

ACCP Guidelines Duration of Therapy Hip Fractures

• Up to Hospital Discharge

• Agents– LMWH

– Fondaparinux

– Warfarin

ACCP Guidelines on Duration of Therapy for Trauma Patients

ACCP Guidelines Length of Prophylaxis

Trauma Population• Exception

– Impaired mobility who undergo inpatient rehabilitation

– Thromboprophylaxis

– LMWH

– Warafarin INR, 2.5

DVT screening

• Physical Exam

• Ascending venography

• Duplex Ultrasonography

• Magnetic Resonance Venography

Physical Examination

• Calf Swelling

• Palpable Venous Cords

• Calf Pain

• Homan’s Sign

• All Unreliable

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

Doppler/Duplex Ultrasound

• Comparable to Venogram• Non Invasive• No Morbidity• Poor Axial (i.e Pelvic)

Vein Evaluation• Operator Dependent• Good Screening Tool

– Noninvasive, reproducible

Magnetic Resonance Venography

• Non Invasive• Good Visualization of

Pelvic Veins• Difficult in Polytrauma

Patient• Excellent specificity and

sensitivity for suspected DVT

• Controversial for screening

Pulmonary Embolism

Clinical

Shortness of breath, agitation, confusion

Laboratory

PaO2, A-a gradient

Diagnostic studies

V/Q scans

Pulmonary Angiogram, CT PA

Ventilation Perfusion Scan

• Ventilation Perfusion mismatch• Results

– Low probabiltity• 15% False Negative

– Medium• Need Angiogram

– High probability• 15% False Positive

• Screening Tool

Pulmonary Angiogram

• Angiographic Evaluation of pulmonary vascular tree

• Allows Placement of IVC Filter in same setting if indicated

• Sensitive - Standard in PE Detection. Diagnostic

Treatment PE

• Anticoagulation

• Filter for recurrent event despite anticoagulation

• Thrombectomy– Serious Acute PE– Patient in extremous– Large identifiable PE

Treatment DVT/PE

• Heparin– Bolus 10-15K units– Continuous Infusion

• 1000Units/Hr– Goal PTT 2x Control

• Prevent Clot propagation and recurrent PE

– Discontinue when Therapeutic on Warfarin

• LMWH / Pentasaccharide– Mass related dose SQ inj

– Single daily dose

– No monitoring necessary

– Discontinue when Therapeutic on Warfarin

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

DVT/PE Outcome

• No Diagnosis and Treatment – 30% Mortality

• Correct Diagnosis and Therapy– 11% Mortality in First Hour– 8% Mortality After First Hour

DVT/PE Outcome• Post Thrombotic Syndrome

– Valvular Incompetence– Venous Stasis– Edema– Cutaneous Atrophy

• Recurrent DVT– 20% of Patients

Bibliography FES/ARDS

• Gurd AR, Wilson RI Fat-embolism syndrome Lancet. 1972 Jul 29;2(7770):231-2

• Giannoudis PV, Pape HC, Cohen AP, Krettek C, Smith RM. Review: systemic effects of femoral nailing: from Küntscher to the immune reactivity era. Clin Orthop Relat Res. 2002 Nov;(404):378-86

• Bosse MJ, MacKenzie EJ, Riemer BL, Brumback RJ, McCarthy ML, Burgess AR, Gens DR, Yasui Y. Adult respiratory distress syndrome, pneumonia, and mortality following thoracic injury and a femoral fracture treated either with intramedullary nailing with reaming or with a plate. A comparative study. J Bone Joint Surg Am. 1997 Jun;79(6):799-809

• Canadian Orthopaedic Trauma Society.Reamed versus unreamed intramedullary nailing of the femur: comparison of the rate of ARDS in multiple injured patients. J Orthop Trauma. 2006 Jul;20(6):384-7

Bibliography DVT/PE

• Geerts WH, Bergqvist D, Pineo GF, Heit JA, Samama CM, Lassen MR, Colwell CW; American College of Chest Physicians Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008 Jun;133(6 Suppl):381S-453S

• Rogers FB, Cipolle MD, Velmahos G, Rozycki G, Luchette FA Practice management guidelines for the prevention of venous thromboembolism in trauma patients: the EAST practice management guidelines work group. J Trauma. 2002 Jul;53(1):142-64

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