Air embolism – central line disruption
Theory
Subclinical air embolism is common. Symptomatic air embolism post CVC line insertion <2%.
Small amount air – subclinical.
Intermediate amounts:
- Collect in pulmonary circulation
- Leads to pulmonary vascular injury: pulmonary vasoconstriction, pulmonary hypertension, endothelial injury and pulmonary oedema
Large amount (3–8 ml/kg) – acute right ventricular outflow obstruction, cardiogenic shock and circulatory collapse.
In setting of ASD/VSD/patent foramen ovale, even small amounts of air can cause peripheral embolisation to territory supplied by blood vessel.
Immediate intern management
Attend patient and make rapid assessment.
If patient unconscious/severe respiratory distress/arrest
- Tell nursing staff to call Code Blue then move to head end of bed.
- Triple manoeuvre – chin lift, jaw thrust, head tilt.
- Bag and mask patient with oxygen.
- Start CPR if arrested.
Patient conscious/mild distress
- Stop central line infusion/clamp line.
- Give 100% oxygen by mask and place patient in trendelenburg position (head down).
- If patient increasingly distressed:
- Rotate to left hand side with right side facing upwards
(left lateral position). (Traps air at apex of ventricle).
- Ask nursing staff to call MET code.
- Get crash trolley, obtain IV access and send off blood tests.
- Notify unit registrar, ICU registrar and anaesthetist on call.
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Clinical features (obtain rapidly)
History
- Incident following CVC line manipulation
- Chest pain
- SOB
- Palpitations
- Neurosensory symptoms
- Events preceding related to CVC line
- Reason for CVC line
- Cause for hospitalisation
Examination
- Airway
- Breathing; ? respiratory distress/failure
- Assessment haemodynamics
- Cardiorespiratory examination
- Cyanosis/mill wheel murmur
- Agitation and altered conscious state
Other (obtain later)
- CVC line
- Type, position, ? last CXR for check position
- When last used
Investigations
- ABG
- Low PaO2
- High PaCO2
- Metabolic acidosis
- ECG
- Tachycardia
- R axis deviation
- RV strain
- ST depression
- CXR
- APO
- Air in pulmonary tree
- Basic blood tests
Further definitive management
Immediate cardiorespiratory support and resuscitation
- Check CVC line while CVC clamped:
- ? Moved/dislodged
- Attempt to aspirate air through CVC (never inject)
- (The catheter may have to be advanced to achieve this. Catheter advancement should only be performed in a monitored environment and using sterile technique)
- In cardiovascular collapse:
- External cardiac compression may expel air from the pulmonary outflow tract into the pulmonary circulation re-establishing pulmonary flow.
- Support the right heart with IV fluids and beta-adrenergic agents.
- Admit patient to ICU
- Consider hyperbaric oxygen therapy (liaise with appropriate facility)
Remember there are more common causes for acute SOB in a patient with a central line: for example, pneumothorax, pulmonary embolus, acute pulmonary oedema, sputum retention and anaphylaxis. Initial assessment should be aimed at ruling out these other causes and then, if they are not present, considering the possibility of air embolus.
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