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Venous Air Embolism Clinical Presentation

  • Author: Brenda L Natal, MD, MPH; Chief Editor: Erik D Schraga, MD  more...
Updated: Dec 08, 2015


Most venous air emboli go unrecognized because their presentations are protean and mimic other cardiac, pulmonary, and neurologic dysfunctions, such as the following (in awake patients)[12, 25] :

  • Acute dyspnea, tachypnea
  • Continuous cough
  • "Gasp" reflex (a classic gasp at times reported when a bolus of air enters the pulmonary circulation and causes acute hypoxemia) [1, 2]
  • Dizziness/lightheadedness/vertigo
  • Nausea
  • Headache, seizures
  • Syncope
  • Substernal chest pain
  • Slurred speech
  • Blurred vision
  • Anxiety/agitation/disorientation/sense of "impeding doom"
  • Ataxia


Because of the lack of specific signs and symptoms of venous air embolism (VAE), a high index of suspicion is necessary to establish the diagnosis and institute the appropriate treatment. The number of procedures that place patients at risk for VAE has increased, and these procedures occur across almost all clinical specialties. This must be considered to aid in the confirmation or ruling out of VAE.

If VAE is suspected, obtain the following key historical elements:

  • Recent surgical procedures especially neurosurgical, otolaryngological, cardiovascular, or orthopedic
  • Scuba diving trips and a history of decompression injuries or decompression sickness
  • Blunt or penetrating trauma to the head, face, neck, thorax, and/or abdomen
  • Invasive therapeutic and/or diagnostic procedures such as central venous catheterization; lumbar puncture; high-pressure infusion of medications, blood products, and/or IV contrast agents
  • Patients with hemodialysis access catheters or other indwelling central venous catheters
  • Patients on positive pressure ventilation
  • Peripartum/postpartum orogenital sex (air may enter veins of the myometrium) [4, 7]
  • Ingestion of hydrogen peroxide (rare)

Physical Examination

Clinical Presentation

Many cases of venous air embolism (VAE) are subclinical and do not result in untoward outcomes. However, severe cases are characterized by cardiovascular collapse and/or acute vascular insufficiency of several specific organs, including, but not limited to, the brain, spinal cord, heart, and skin. As mentioned earlier, the spectrum of effects is largely dependent on the rate and volume of entrained VAE.[1, 6, 11]

Two additional contributing factors include whether or not the patient is spontaneously breathing (yielding negative thoracic pressure) or is under controlled positive pressure ventilation.[1]  These two factors facilitate the entry of air down a pressure gradient. The clinical presentation is also dependent on the patient's body position at the time of the event. Generally, if the patient is in a sitting position, gas will travel retrograde via the internal jugular vein to the cerebral circulation, leading to neurologic symptoms secondary to increased intracranial pressure. In a recumbent position, gas proceeds into the right ventricle and pulmonary circulation, subsequently causing pulmonary hypertension and systemic hypotension.[11]

An arterial air embolism can also form if passage of air occurred through a right-to-left shunt, as in the case of a patent foramen ovale.[2, 3]  The arterial air emboli can then lodge in the coronary or cerebral circulation, causing myocardial infarction or stroke.


The following hemodynamic, pulmonary, and neurologic complications primarily result from gas gaining entry into the systemic circulation, occluding the microcirculation and causing ischemic damage to these end organs. Animal studies have also suggested the presence of secondary tissue damage resulting from the release of inflammatory mediators and oxygen free radicals that occur in response to air embolism.

Cardiovascular signs include the following

  • Dysrhythmias (tachyarrhythmias/bradycardias)
  • "Mill wheel" murmur - A temporary loud, machinerylike, churning sound due to blood mixing with air in the right ventricle, best heard over the precordium (a late sign) [2, 9, 11]
  • JVD
  • Hypotension
  • Myocardial ischemia
  • Nonspecific ST-segment and T-wave changes and/or evidence of right heart strain [1, 2, 33]
  • Pulmonary artery hypertension
  • Increased CVP
  • Circulatory shock/cardiovascular collapse

Pulmonary features include the following:

  • Adventitious sounds (rales, wheezing)
  • Tachypnea
  • Hemoptysis
  • Cyanosis
  • Decreased end-tidal carbon dioxide, arterial oxygen saturation, and tension
  • Hypercapnia
  • Increased pulmonary vascular resistance and airway pressures
  • Pulmonary edema
  • Apnea

Neurologic findings include the following:

  • Acute altered mental status
  • Seizures
  • Transient/permanent focal deficits (weakness, paresthesias, paralysis of extremities)
  • Loss of consciousness, collapse
  • Coma (secondary to cerebral edema)

Funduscopic examination may reveal ophthalmologic signs such as air bubbles in the retinal vessels.[14]

Dermatologic evaluation may reveal crepitus over superficial vessels (rarely seen in setting of massive air embolus) and/or livedo reticularis.

Contributor Information and Disclosures

Brenda L Natal, MD, MPH Assistant Professor of Emergency Medicine, Simulation Director, Rutgers New Jersey Medical School; Attending Physician, Department of Emergency Medicine, University Hospital of Newark

Brenda L Natal, MD, MPH is a member of the following medical societies: American College of Emergency Physicians, American Medical Association

Disclosure: Nothing to disclose.


Christopher I Doty, MD, FAAEM, FACEP Associate Professor of Emergency Medicine, Residency Program Director, Vice-Chair for Education, Department of Emergency Medicine, University of Kentucky-Chandler Medical Center

Christopher I Doty, MD, FAAEM, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

David Eitel, MD, MBA Associate Professor, Department of Emergency Medicine, York Hospital; Physician Advisor for Case Management, Wellspan Health System, York

David Eitel, MD, MBA is a member of the following medical societies: American College of Emergency Physicians, American Society of Pediatric Nephrology, Society for Academic Emergency Medicine, Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

Daniel J Dire, MD, FACEP, FAAP, FAAEM Clinical Professor, Department of Emergency Medicine, University of Texas Medical School at Houston; Clinical Professor, Department of Pediatrics, University of Texas Health Sciences Center San Antonio

Daniel J Dire, MD, FACEP, FAAP, FAAEM is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Pediatrics, American Academy of Emergency Medicine, American College of Emergency Physicians, Association of Military Surgeons of the US

Disclosure: Nothing to disclose.


The authors and editors of Medscape Drugs & Diseases gratefully acknowledge the contributions of previous authors, Andrew G Wittenberg, MD, MPH; Allison J Richard, MD; and Steven A Conrad, MD, PhD, to the development and writing of this article.

  1. Mirski MA, Lele AV, Fitzsimmons L, Toung TJ. Diagnosis and treatment of vascular air embolism. Anesthesiology. 2007 Jan. 106(1):164-77. [Medline].

  2. Sviri S, Woods WP, van Heerden PV. Air embolism--a case series and review. Crit Care Resusc. 2004 Dec. 6(4):271-6. [Medline].

  3. van Hulst RA, Klein J, Lachmann B. Gas embolism: pathophysiology and treatment. Clin Physiol Funct Imaging. 2003 Sep. 23(5):237-46. [Medline].

  4. Muth CM, Shank ES. Gas embolism. N Engl J Med. 2000 Feb 17. 342(7):476-82. [Medline].

  5. Wong AY, Irwin MG. Large venous air embolism in the sitting position despite monitoring with transoesophageal echocardiography. Anaesthesia. 2005 Aug. 60(8):811-3. [Medline].

  6. Pronovost PJ, Wu AW, Sexton JB. Acute decompensation after removing a central line: practical approaches to increasing safety in the intensive care unit. Ann Intern Med. 2004 Jun 15. 140(12):1025-33. [Medline]. [Full Text].

  7. Moon RE. Air or gas embolism. Feldmeier JJ. Hyperbaric Oxygen Therapy: Committee Report. Kensington, MD: Undersea and Hyperbaric Medical Society; 2003. 5-10.

  8. Ho AM, Ling E. Systemic air embolism after lung trauma. Anesthesiology. 1999 Feb. 90(2):564-75. [Medline].

  9. Platz E. Tangential Gunshot Wound to the Chest Causing Venous Air Embolism: A Case Report and Review. J Emerg Med. 2008 Sep 15. [Medline].

  10. Imai S, Tamada T, Gyoten M, Yamashita T, Kajihara Y. Iatrogenic venous air embolism caused by CT injector--from a risk management point of view. Radiat Med. 2004 Jul-Aug. 22(4):269-71. [Medline].

  11. Sheasgreen J, Terry T, Mackey JR. Large-volume air embolism as a complication of augmented computed tomography: case report. Can Assoc Radiol J. 2002 Oct. 53(4):199-201. [Medline]. [Full Text].

  12. Fibel KH, Barnes RP, Kinderknecht JJ. Pressurized intravenous fluid administration in the professional football player: a unique setting for venous air embolism. Clin J Sport Med. 2015 Jul. 25 (4):e67-9. [Medline].

  13. Kapoor T, Gutierrez G. Air embolism as a cause of the systemic inflammatory response syndrome: a case report. Crit Care. 2003 Oct. 7(5):R98-R100. [Medline]. [Full Text].

  14. Ho AM. Is emergency thoracotomy always the most appropriate immediate intervention for systemic air embolism after lung trauma?. Chest. 1999 Jul. 116(1):234-7. [Medline]. [Full Text].

  15. Leitch DR, Green RD. Pulmonary barotrauma in divers and the treatment of cerebral arterial gas embolism. Aviat Space Environ Med. 1986 Oct. 57(10 Pt 1):931-8. [Medline].

  16. Schellart NA, Sterk W. Venous gas embolism after an open-water air dive and identical repetitive dive. Undersea Hyperb Med. 2012 Jan-Feb. 39(1):577-87. [Medline].

  17. Palmon SC, Moore LE, Lundberg J, Toung T. Venous air embolism: a review. J Clin Anesth. 1997 May. 9(3):251-7. [Medline].

  18. Zargaraff G, Zucker M. Radiology Challenge: The Sudden Death. Israeli Journal of Emergency Medicine. Oct 2005;. 5(4):49-51.

  19. Karaosmanoglu D, Oktar SO, Araç M, Erbas G. Case report: Portal and systemic venous gas in a patient after lumbar puncture. Br J Radiol. 2005 Aug. 78(932):767-9. [Medline].

  20. Schlundt J, Tzanova I, Werner C. A case of intrapulmonary transmission of air while transitioning a patient from a sitting to a supine position after venous air embolism during a craniotomy. Can J Anaesth. 2012 May. 59(5):478-482. [Medline].

  21. Longatti P, Marton E, Feletti A, Falzarano M, Canova G, Sorbara C. Carbon dioxide field flooding reduces the hemodynamic effects of venous air embolism occurring in the sitting position. Childs Nerv Syst. 2015 Aug. 31 (8):1321-6. [Medline].

  22. Lew TW, Tay DH, Thomas E. Venous air embolism during cesarean section: more common than previously thought. Anesth Analg. 1993 Sep. 77(3):448-52. [Medline].

  23. Fong J, Gadalla F, Druzin M. Venous emboli occurring caesarean section: the effect of patient position. Can J Anaesth. 1991 Mar. 38(2):191-5. [Medline].

  24. Scoletta P, Morsiani E, Ferrocci G, Maniscalco P, Pellegrini D, Colognesi A, et al. [Carbon dioxide embolization: is it a complication of laparoscopic cholecystectomy? ]. Minerva Chir. 2003 Jun. 58(3):313-20. [Medline].

  25. Yesilaras M, Atilla OD, Aksay E, Kilic TY. Retrograde cerebral air embolism. Am J Emerg Med. 2014 Dec. 32 (12):1562.e1-2. [Medline].

  26. Orebaugh SL. Venous air embolism: clinical and experimental considerations. Crit Care Med. 1992 Aug. 20(8):1169-77. [Medline].

  27. Imai S, Tamada T, Gyoten M, Yamashita T, Kajihara Y. Iatrogenic venous air embolism caused by CT injector--from a risk management point of view. Radiat Med. 2004 Jul-Aug. 22(4):269-71. [Medline].

  28. Lou S, Ji B, Liu J, Yu K, Long C. Generation, detection and prevention of gaseous microemboli during cardiopulmonary bypass procedure. Int J Artif Organs. 2011 Nov. 34(11):1039-51. [Medline].

  29. Vesely TM. Air embolism during insertion of central venous catheters. J Vasc Interv Radiol. 2001 Nov. 12(11):1291-5. [Medline].

  30. Trunkey D. Initial treatment of patients with extensive trauma. N Engl J Med. 1991 May 2. 324(18):1259-63. [Medline].

  31. Cheng CK, Chang TY, Liu CH, et al. Presence of gyriform air predicts unfavorable outcome in venous catheter-related cerebral air embolism. J Stroke Cerebrovasc Dis. 2015 Oct. 24 (10):2189-95. [Medline].

  32. Ganslandt O, Merkel A, Schmitt H, et al. The sitting position in neurosurgery: indications, complications and results. a single institution experience of 600 cases. Acta Neurochir (Wien). 2013 Oct. 155(10):1887-93. [Medline].

  33. Novack V, Shefer A, Almog Y. Images in cardiology. Coronary air embolism after removal of central venous catheter. Heart. 2006 Jan. 92(1):39. [Medline].

  34. Gracia I, Fabregas N. Craniotomy in sitting position: anesthesiology management. Curr Opin Anaesthesiol. 2014 Oct. 27 (5):474-83. [Medline].

  35. Maddukuri P, Downey BC, Blander JA, Pandian NG, Patel AR. Echocardiographic diagnosis of air embolism associated with central venous catheter placement: case report and review of the literature. Echocardiography. 2006 Apr. 23(4):315-8. [Medline].

  36. Tins BJ, Cassar-Pullicino VN, Lalam R, Haddaway M. Venous air embolism in consecutive balloon kyphoplasties visualised on CT imaging. Skeletal Radiol. 2012 Jan 15. [Medline].

  37. Archer DP, Pash MP, MacRae ME. Successful management of venous air embolism with inotropic support. Can J Anaesth. 2001 Feb. 48(2):204-8. [Medline].

  38. Ohashi S, Endoh H, Honda T, Komura N, Satoh K. Cerebral air embolism complicating percutaneous thin-needle biopsy of the lung: complete neurological recovery after hyperbaric oxygen therapy. J Anesth. 2001. 15(4):233-6. [Medline].

  39. Yesilaras M, Atilla OD, Aksay E, Kilic TY. Retrograde cerebral air embolism. Am J Emerg Med. 2014 Dec. 32 (12):1562.e1-2. [Medline].

  40. Gracia I, Fabregas N. Craniotomy in sitting position: anesthesiology management. Curr Opin Anaesthesiol. 2014 Oct. 27 (5):474-83. [Medline].

  41. Zakhari N, Castillo M, Torres C. Unusual cerebral emboli. Neuroimaging Clin N Am. 2016 Feb. 26 (1):147-63. [Medline].

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