Air Embolism in Vascular Access: Prevention, Recognition, and Emergency Management

Venous air embolism (VAE) is a rare but potentially catastrophic complication of central vascular access devices. When air enters the central venous system, it travels to the right heart and pulmonary vasculature, where it can cause immediate cardiovascular collapse. Because most causes of air embolism during vascular access care are preventable with known techniques, every clinician who inserts, accesses, or removes a central catheter must understand the prevention principles.

Parent guide: Catheter Complications: Complete Clinical Reference

Pathophysiology

How Air Enters the System

Air enters the central venous circulation when the catheter lumen is open to the atmosphere and conditions favor air entry:

Pressure gradient: The central venous pressure (CVP) in the SVC is typically 2–8 mmHg at rest. During inspiration, intrathoracic pressure drops, pulling CVP toward zero or negative in some patients. Any time a catheter hub or connector is open to air during inspiration, the negative venous pressure creates a gradient that draws air into the lumen.

High-risk scenarios:

• Hub left open or uncapped during tubing change
• Tubing disconnection (accidental or during dressing change)
• Catheter removal — the fibrin track around the catheter remains patent for minutes after catheter removal, providing a direct channel from atmosphere to the venous system
• Catheter fracture with atmospheric air entering at the fracture site
• During insertion with stylet or dilator removal before catheter placement

What Happens When Air Enters

Small amounts (<20 mL in adults): May be tolerated without symptoms or with transient mild dyspnea.

Clinically significant (>50 mL in adults; much less in children): Air collects in the right ventricular outflow tract, creating an “air lock” that prevents forward flow. This causes:

• Sudden right heart failure
• Cardiovascular collapse
• Cerebral hypoperfusion
• Paradoxical embolism (air through patent foramen ovale into systemic circulation)

Lethal dose in adult humans: Estimated 200–300 mL (rapidly introduced); fatal cases reported with smaller volumes in compromised patients.

High-Risk Vascular Access Scenarios

Catheter Insertion

The moment between dilator/stylet removal and catheter advancement is the highest-risk insertion period — the introducer sheath is open to the atmosphere while the patient breathes.

Prevention:

• Trendelenburg position increases CVP, reducing the air-entry pressure gradient
• Thumb occlusion of sheath hub between steps
• Instruct patient to hold breath or perform Valsalva at the moment of open exposure

Hub/Connector Disconnection

Accidental tubing disconnection exposes the catheter hub to the atmosphere.

Prevention:

• Ensure all Luer-lock connections are secure (tighten at every dressing change and tubing change)
• Apply needle-free connectors to all unused lumens at all times
• Never leave a catheter hub uncapped, even briefly

Tubing Changes

Deliberate disconnection for tubing changes is a planned exposure moment.

Prevention:

• Position patient in Trendelenburg (head down) during tubing changes for CVADs if clinically feasible
• Instruct patient to perform Valsalva or exhale and hold breath during the moment of tubing disconnection and reconnection
• Clamp the catheter (if clamp is available on the catheter design) before opening connections

Catheter Removal

PICC, CVC, and tunneled catheter removal is the highest-risk post-insertion air embolism moment. After catheter removal, a patent fibrin-lined track from skin to vein remains for up to several minutes. If the patient is upright and breathing normally, this track can admit air on inspiration.

Prevention protocol (critical):

1. Position patient supine or Trendelenburg (head-down) — do NOT remove central catheter with patient sitting up
2. Instruct patient to perform Valsalva at the moment of catheter tip passing through the skin — increased intrathoracic pressure elevates CVP and prevents air entry
3. If Valsalva is difficult (patient too ill, non-cooperative): instruct to exhale and hold breath
4. After removal: apply immediate firm pressure with dry gauze
5. Apply occlusive dressing (petroleum gauze or TSM dressing) to the exit wound — maintain for at least 30–60 minutes to allow fibrin track closure
6. Document occlusive dressing applied and dwell time

Recognition: Clinical Presentation

Air embolism may present with a spectrum of severity:

Mild:

• Sudden onset mild dyspnea
• Cough
• Chest discomfort
• Lightheadedness or dizziness during or immediately after a catheter manipulation event

Moderate:

• Tachypnea, significant dyspnea
• Decreased oxygen saturation
• Tachycardia, anxiety
• “Sucking” or gurgling sound audible during catheter disconnection

Severe (massive air embolism):

• Sudden cardiovascular collapse
• Severe hypotension
• Loss of consciousness
• “Mill-wheel” murmur: Churning systolic-diastolic murmur audible over the precordium with a stethoscope — represents air in the right heart; pathognomonic but not always present
• Cardiac arrest (pulseless electrical activity or ventricular fibrillation)

Paradoxical air embolism (air crosses to systemic circulation through patent foramen ovale):

• Focal neurologic deficits
• Stroke-like presentation
• Acute coronary syndrome pattern

Emergency Management

Immediate Response (Activate at First Suspicion)

1. Call for help: Activate emergency response; notify provider immediately
2. Occlude the catheter: Clamp the catheter; if hub is open, cover immediately with thumb
3. Position: Place patient in left lateral decubitus (Durant’s maneuver) combined with Trendelenburg (head down)
   • Left lateral decubitus rotates the air away from the right ventricular outflow tract, allowing blood to flow around the air bolus
   • Trendelenburg reduces further air entry and improves cerebral perfusion
4. High-flow oxygen: 100% O2 via non-rebreather mask — increases nitrogen washout, reducing bubble size; if patient is intubated, 100% FiO2
5. IV access: Ensure adequate IV access for resuscitation

Durant’s Maneuver

Left lateral decubitus + Trendelenburg is the single most important positional intervention for venous air embolism. This combination:

• Moves air from the right ventricular outflow tract to the apex of the right ventricle, where it is away from the pulmonary outflow
• Allows the right ventricle to continue ejecting blood around the trapped air pocket
• Is often life-saving when applied immediately

Aspiration

If the central catheter is still in place and there is suspected significant air embolism in the right heart:

• Aspirate from the central catheter — air may be aspirated back through the catheter
• This is most effective when the catheter tip is at the right atrium level (catheter may need to be advanced by provider)
• Aspirate slowly in 10 mL increments

Hyperbaric Oxygen

Hyperbaric oxygen (HBO) reduces bubble size by increasing the partial pressure of ambient oxygen, forcing nitrogen out of the bubbles. Indicated for:

• Significant neurologic injury from paradoxical air embolism
• Persistent cardiovascular instability despite initial management
• Arrange transfer to hyperbaric facility if clinically feasible and patient stable enough for transport

Cardiopulmonary Resuscitation

If cardiac arrest occurs: initiate CPR immediately. Chest compressions may fragment the air bubble and improve right ventricular outflow. Continue CPR while simultaneously pursuing aspiration and positioning.

Documentation After Suspected Air Embolism

Document immediately:

• Time of suspected event
• Activity at time of event (catheter removal, tubing change, hub exposure)
• Initial symptoms
• Position at time of event
• Interventions: position change, oxygen, aspiration
• Patient response
• Provider notification time and response
• Patient disposition

Report as a safety event per institutional incident reporting protocol.

Prevention Summary Checklist

Related Resources

Related guides:

• PICC Care and Maintenance
• Non-Tunneled CVC Guide

Related policies:

• Air Embolism — Vascular Access

References

1. Gorski LA, et al. (2021). INS Infusion Therapy Standards of Practice (Standard 58: Air Embolism). J Infus Nurs, 44(Suppl 1).
2. Mirski MA, et al. (2007). Diagnosis and treatment of vascular air embolism. Anesthesiology, 106(1):164–177.
3. Durant TM, et al. (1947). Pulmonary (venous) air embolism. Am Heart J, 33(2):269–281. [Historical Durant’s maneuver description]
4. Heckmann JG, et al. (2000). Neurological manifestations of cerebral air embolism. J Neurol, 247(3):229–233.
5. Troianos CA, et al. (2011). Guidelines for performing ultrasound guided vascular cannulation. J Am Soc Echocardiogr, 24(12):1291–1318.