Venous Air EmbolismVenous Air Embolism

Pekka Talke, MDPekka Talke, MD

University of California, San FranciscoUniversity of California, San Francisco

20092009

Procedures in Sitting PositionProcedures in Sitting Position

• Cervical laminectomiesCervical laminectomies

• Posterior fossa surgeriesPosterior fossa surgeries

• Becoming relatively uncommon but Becoming relatively uncommon but associated with high rates of complicationsassociated with high rates of complications

Benefits of Sitting PositionBenefits of Sitting Position

• Better surgical exposureBetter surgical exposure

• Less tissue retractionLess tissue retraction

• Less bleedingLess bleeding

• Less cranial nerve damageLess cranial nerve damage

Complications of Sitting PositionComplications of Sitting Position

• Spinal cord infarctSpinal cord infarct

• Ulnar nerve compressionUlnar nerve compression

• Sciatic nerve damageSciatic nerve damage

• Lateral peroneal nerve compressionLateral peroneal nerve compression

• Cardiovascular changesCardiovascular changes

• Airway obstruction -tube kinking, migrationAirway obstruction -tube kinking, migration

• Tension pneumocephalusTension pneumocephalus

• Venous Air Embolism (VAE) (40%)Venous Air Embolism (VAE) (40%)

VAE detection,VAE detection, sensitivitysensitivity

Doppler, TEEDoppler, TEE

ET NET N22

PaOPaO22

ET COET CO22, PAP, PAP

PaCOPaCO22

CVPCVP

COCO

BPBP

ECG, esoph. steth.ECG, esoph. steth.

Monitoring for Sitting PositionMonitoring for Sitting Position

• ECG ECG

• TemperatureTemperature

• Muscle relaxationMuscle relaxation

• Pulse oximeterPulse oximeter

• ET COET CO22, ET anesthetic agent, ET N, ET anesthetic agent, ET N22

• Arterial blood pressure (cpp)Arterial blood pressure (cpp)

• Central venous pressure (cvp, pap)Central venous pressure (cvp, pap)

• Precordial DopplerPrecordial Doppler

• Esophageal stethoscopeEsophageal stethoscope

Monitoring for Sitting PositionMonitoring for Sitting Position

• ECG ECG

• TemperatureTemperature

• Muscle relaxationMuscle relaxation

• Pulse oximeterPulse oximeter

• ET COET CO22, ET anesthetic agent, ET N, ET anesthetic agent, ET N22

• Arterial blood pressure (cpp)Arterial blood pressure (cpp)

• Central venous pressure (cvp, pap)Central venous pressure (cvp, pap)

• Precordial DopplerPrecordial Doppler

• Esophageal stethoscopeEsophageal stethoscope

Doppler (VAE)Doppler (VAE)

• Very sensitiveVery sensitive

• 3-6 th interspace, right of sternum3-6 th interspace, right of sternum

• 2.2 MHz probe2.2 MHz probe

• Blood, wall motion, air Blood, wall motion, air

• Early detection/preventionEarly detection/prevention

Doppler Doppler equipmentequipment

Doppler Doppler probeprobe

2.25 MHz flat probe

3/4’’ ultrasound beam at surface

Doppler Doppler equipmentequipment

Model 915-BL orModel 614-B

2 MHz flat probe

Doppler Doppler equipmentequipment

Precordial Doppler PlacementPrecordial Doppler Placement

Doppler Doppler record keepingrecord keeping

ET COET CO22 changes with VAE changes with VAE

• Sudden decrease in ET COSudden decrease in ET CO22 within a few breaths after within a few breaths after

VAEVAE

• ET COET CO22 decrease proportional to VAE magnitude decrease proportional to VAE magnitude

• ET COET CO22 starts to recover once VAE stops starts to recover once VAE stops

ET COET CO22 trend changes with VAE trend changes with VAE

CVP catheter (VAE)CVP catheter (VAE)

• Positioning: ECG, X-ray, pressure tracingPositioning: ECG, X-ray, pressure tracing

• Positioning in sitting position - migrationPositioning in sitting position - migration

• Can be used to confirm Doppler placementCan be used to confirm Doppler placement

• Aspiration: confirmation of VAE, treatment?Aspiration: confirmation of VAE, treatment?

• (PA catheter: diagnosis, resolution) (PA catheter: diagnosis, resolution)

CVP CatheterCVP Catheter

CVP CatheterCVP Catheter

CVP CatheterCVP Catheter

CVP CatheterCVP Catheter

Placement of CVP CatheterPlacement of CVP Catheter

From Clinical Neuroanesthesia, Cucchiara et al

Placement of CVP CatheterPlacement of CVP Catheter

From Clinical Neuroanesthesia, Cucchiara et al

VAE Detection - AwakeVAE Detection - Awake

• CoughCough

• Chest painChest pain

• BronchospasmBronchospasm

• HypoxiaHypoxia

Rapid, Large VAERapid, Large VAE

• RareRare

• CatastrophicCatastrophic

• Air lock in right heart Air lock in right heart

• Right sided heart failure Right sided heart failure

• Reduced CO Reduced CO

• Cardiovascular collapseCardiovascular collapse

Slow, Continuous VAESlow, Continuous VAE

• CommonCommon

• Air bubbles entrapped in pulmonary circulationAir bubbles entrapped in pulmonary circulation

• Local hypoxemia/obstruction Local hypoxemia/obstruction

• Sympathetic reflex vasoconstriction Sympathetic reflex vasoconstriction

• Pulmonary HTN, hypoxemia, COPulmonary HTN, hypoxemia, CO22 retention, increased retention, increased

dead space, decreased ET COdead space, decreased ET CO22

• BronchoconstrictionBronchoconstriction

M&M from VAEM&M from VAE

• Right heart failureRight heart failure

• Hypoxia - immediate, delayed (ARDS)Hypoxia - immediate, delayed (ARDS)

• Paradoxical Air Embolus (PAE)Paradoxical Air Embolus (PAE)– incidence unknown– potential for neurologic deficits– PFO (20-30%)

Treatment of VAETreatment of VAE

• 100% O100% O22

• Flood field, bone waxFlood field, bone wax

• Jugular pressureJugular pressure

• Volume, vasopressors, supineVolume, vasopressors, supine

• CPR CPR

Venous Air EmbolismVenous Air Embolism

• Prevention - avoid hypovolemia, good surgical Prevention - avoid hypovolemia, good surgical techniquetechnique

• Early detectionEarly detection

• Treatment Treatment

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