AIR EMBOLISM SYNDROME

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AIR EMBOLISM SYNDROME
www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
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• Air enters the vasculature
• ?
• Pulmonary circulation
• ?
• Circulatory/Respiratory
• embarassment

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PATHOPHYSIOLOGY

• Gas in vein
• ?
• Travels to right heart and lungs
• ?
• Systemic circulation
• (If PFO is present)

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Entry of air

• Abnormal communication between air and blood
  vessel
• Pressure gradient
• Trauma
• Surgical incision
• Intravascular catheters
• Mechanical ventilation in patients with damaged
  lungs

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Etiology

• Surgery Trauma related

• Non surgical

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Surgical

• Neurosurgery
• Liver transplant
• Total hip replacement
• Harrington rod insertion
• Spinal fusion
• Pulsed saline irrigation
• Removal of tissue expanders
• TURP
• Caesarean section

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• Arthroscopy
• Open heart surgery
• Hysterectomy
• Head neck trauma
• Dental implant surgery
• Pacemaker insertion
• IABP
• Bone marrow harvest

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• Epidural catheter placement
• Central line removal
• Percutaneous lung biopsy
• Pulmanary contusion
• Laser bronchoscopy
• Retrograde pyelography
• Haemodialysis
• Percutaneous lithotripsy

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Non surgical

• CPR
• GI endoscopy
• PPV
• Barotrauma
• Contrast infusion CT scan
• SCUBA diving

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Circulatory consequences

• Massive air embolism
• ?
• Fills right heart
• ?
• impedes venous return
• ?
• stops circulation

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• gt100 ml of air must be acutely infused to arrest
  circulation.
• In animal experiments,rate of venous air infusion
  .03ml/kg/mt
• In an 70 kg adult,_at_21ml/mt.

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• Air passes through right
• heart to the lungs
• ?
• raises PA pressure
• ?
• respiratory consequences

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Respiratory consequences

• Air embolizes in pulmonary
• arterioles capillaries
• ?
• Abnormal air blood interface
• ?
• Denatures plasma proteins

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• Amorphous proteinaceous cellular debris
  created at the surface of air bubbles
• ?
• Attracts and activates WBCs
• ?
• Injury to pulmonary capillaries
• ?
• ? capillary permeability
• ?
• Alveolar flooding
• ?
• Non cardiogenic pulmonary edema

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• Arterial circulation is protected by
  filtering effect of pulmonary circulation
• Large amount of air
• Lungs cant filter the air completely.

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• Right heart ? bubbles can pass to left side
• Pressure left sidegtright side
• Significant pulmonary embolisation ?es right
  heart pressure
• ?
• Reversal of interatrial gradient
• ?
• Systemic embolisation

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• Bronchoconstriction
• Hypoxemia
• VQ mismatch
• ?
• ? dead space
• ?
• ?EtCO2

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Extrathoracic manifestations

• If air directly enters pulmonary veins
• ?
• Bubbles pass to arterial circulation
• ?
• Peripheral embolisation
• ?
• Ischemic manifestations

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• Brain
• Heart
• Skin (livedo reticularis)

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• Some of ischemic manifestations are mediated by
  PMN WBCs O2 radicals.

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Presentation

• Acute hypoxemic respiratory failure
• Acute hypoperfusion
• Peripheral embolisation

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• Symptoms, which develop immediately following
  embolization, are similar to pulmonary
  thromboembolism. Severity of symptoms is related
  to degree of air entry and include the following
• Dyspnea
• Chest pain
• Tachycardia
• Hypotension
• Altered sensorium
• Circulatory shock or sudden death (patients with
  severe VAE)

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• Physical
• Acute respiratory distress
• Tachypnea
• Tachycardia
• Agitation
• Disorientation
• Classic finding - Mill wheel murmur upon
  auscultation of the heart
• Cyanosis and hypotension - Accompany severe VAE

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DIAGNOSIS

• Laboratory studies-
• Hypoxia
• Hypercapnia
• Metabolic acidosis
  
  

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• Chest X-Ray-
• Air in pulmonary arterial system
• Pulmonary arterial dilatation
• Focal oligemia (Westermark sign)
• Pulmonary edema
• Diffuse alveolar filling

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• ECG-
• Tachycardia
• Right axis deviation
• Right ventricular strain
• ST Depression

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• Transthoracic/transesophageal Echocardiography-
• Air in right ventricular outflow
  
• tract/major pulmonary veins
• Precordial Doppler
• Right or left 2nd to 4th
  intercostal
• space in parasternal location.

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• TEE gt Precordial doppler
• Identifies R?L shunting of air.
• Emboli as small as 2µ can be detected.
• Signal audiomodulated
• 0.5ml Air bubbles heard.

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• Safety during prolonged use
• not well established.
• Radiofrequency signal of the surgical diarthermy
  interferes with doppler signal.
  

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• EtCO2 ?es.
• Combination of precordial doppler EtCO2 highly
  sensitive and specific.
• ? end tidal arterial blood CO2 gradient.
• (lt0.5)
• ?ed CVP.

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Differential Diagnosis

• Noncardiogenic pulmonary edema
• Cardiogenic pulmonary edema
• Volume overload
• Sepsis
• Gastric acid aspiration

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Management

• Prevent reembolisation
• Support respiration circulation
• Identify close source of air entry.
• ? gradient
• Notify surgeon
• Flood operating field with saline
• FiO2 1
• Pressors ionotropes
• Jugular compression
• Retrieve air
  

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Standard Treatment

• Mechanical ventilation
• ?es work of breathing
• Corticosteroids
• Anti-inflammatory drugs
• Agents against O2 free radicals

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• Hyperbaric treatment
• ?es surface area for activation of
• WBCs
• Standard treatment for
• SCUBA divers

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• Emergency Department Care
• Once VAE is suspected, any central line procedure
  in progress is immediately terminated and the
  line is clamped.
• Do not withdraw the catheter at this time unless
  it cannot be clamped.

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• Promptly place patient in Trendelenburg position
  and rotate toward the left lateral decubitus
  position. This maneuver helps trap air in the
  apex of the ventricle, prevents its ejection into
  the pulmonary arterial system, and maintains
  right ventricular output.
• Administer 100 oxygen and intubate for
  significant respiratory distress or refractory
  hypoxemia

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• If CV catheter is present, aspirate from the
  distal port and attempt to remove air. Catheter
  may have to be advanced for this to be
  successful.
• In circulatory collapse, external cardiac
  compression may help expel air from the pulmonary
  outflow tract and disperse it into the peripheral
  pulmonary venous system. Support right
  ventricular function with fluid administration
  and beta-adrenergic agents, if indicated.
•    

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• Experience with hyperbaric oxygen therapy for VAE
  is limited, but experience suggests significant
  efficacy. If this modality is available, arrange
  transportation to a hyperbaric facility without
  delay.

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FAT EMBOLISM SYNDROME

• Fat particles in microcirculation of lungs
  
• Lung dysfunction
• Neurologic manifestations
• Petechiae

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Causes

• Traumatic
• Long bone s(2-20)
• Orthopaedic surgery
• Blunt trauma to fatty organs
• Liposuction
• Bone marrow biopsy

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Non Traumatic

• Pancreatitis
• Diabetes mellitus
• Lipid infusions
• Sickle cell crisis
• Burns
• Cardiopulmonary byepass
• Decompression sickness
• Corticosteroids therapy

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• Osteomyelitis
• Alcoholic fatty liver
• Acute fatty liver of pregnancy
• Lymphangiography
• Cyclosporine infusion

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Pathophysiology

• Traumatic
• bone?neutral fat
• embolisation to pulmonary
• vasculature
• hydrolysis of fat
• ?
• toxic free fatty acids
• ?
• endothelial injury

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Non Traumatic

• Hypothesis
• fat arises from lipids in blood.
• ?CRP - trauma
• sepsis
• inflammatory disorders

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• serum of acutely ill patients has the capacity
  to agglutinate chylomicrons
• , VLDL liposomes of nutritional fat
• emulsions
• -CRP provokes Ca dependent agglutination of each
  of these lipid containing substances.

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Systemic Findings

• Venous fat emboli across pulmonary circulation
• ? right heart pressures
• ?
• may open PFO
• deformable fat emboli
• enter systemic circulation
• (fatal)
  

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Clinical Manifestations

• 12-72 hrs latent interval
• ARDS
• Dyspnoea
• Hypoxemia
• Diffuse lung lesion
• Confusion
• Obtundation
• Coma (cerebral fat embolism)

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• Petechiae
• Skin-upper chest,neck and face
• Retinal vessels Purtshers
• Retinopathy
• Thrombocytopenia
• Anemia
• Full blown acute right heart syndrome

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DIAGNOSIS

• Gurds Criteria
• MAJOR
• MINOR
• One major four minor

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Diagnosis

• Major criteria
• Petechiae (conjuctiva,axilla)-20-50cases
• PaO2 lt60
• FiO2 gt0.4
• CNS depression
• Pulmonary edema
• Thrombocytopenia gt50?

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• Minor criteria
• Heart rate gt110
• Fever gt38.5
• Emboli on fundoscopic
• examination
• Fat globules in urine
• Unexplained anemia,gt20 ?
• ? ESR,gt71mm/hr
• Fat in sputum

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Diagnosis (contd)

• Fat globules in urine neither sensitive nor
  specific
• BAL -fat may be of help.
• C-Xray-snow storm appearance-middle upper
  lobes.

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Prophylaxis Treatment

• Early fixation of long bone fractures
• main stay
• ?es FES incidence
• ARDS
• Length of stay
• Methylprednisolone

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• Treat ARDS
• No clear role for glucose,insulin,heparin,ethanol,
  albumin

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Prognosis

• Mortality 5-15
• Supportive Treatment- main stay

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THANK YOU
www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
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