Central lines are essential for the care of many patients, however we estimate at least one patient dies worldwide every day from central line related air emboli. The image above is from a CNN report – one of thousands of similar cases.
All of these cases are avoidable.
Frequently Asked Questions (please click on links in red):
- What is an air embolus and how do they occur?
- How frequently do central line air emboli occur and where is the evidence to support this claim?
- What should we do when a patient requires their central line to be removed but they can’t lie flat?
- This issue persists despite education & policy writing – why is this and how else can we remind staff to remove central lines supine?
- How can we stop those air emboli which occur from accidental central line disconnection?
- How might we reduce air emboli which occur during central line insertion?
- Why hasn’t the magnitude of this issue been recognised before?
Awareness about this issue is poor, and solutions so far implemented have had limited effect. We need to appreciate the complexity of our work environments and apply human factors engineering if we are to prevent these iatrogenic complications.
The power is in your hands to make a difference. Review and implement these 5 effective solutions:
You can help right now by signing this petition (see here) which goes straight to sterile dressing manufacturers asking them to imprint a point of care reminder on sterile dressings for central lines which states: ‘REMOVE CENTRAL LINES SUPINE’ ‘TO AVOID AIR EMBOLI’
Frequently Asked Questions:
How frequently do central line air emboli occur and where is the evidence to support this claim?
How frequently do central line related air emboli deaths occur? (see here):
Even the most conservative estimates (5million CVCs per year in US, air embolus 0.1% of CVCs, and 23% mortality) indicate 1,150 deaths per year from this avoidable complication in the US alone. We’ve provided a list of numerous case reports and case series below.
Does education and experience help reduce the incidence? (see here)
Unfortunately studies suggest that those with greater experience may be less likely to follow appropriate procedures to minimise the risk of CVC related air embolus. Also the impact of education tends to wane rapidly with time.
If CVC related air embolus is so prevalent where are all the reports?
Below we’ve collated numerous case series and an overwhelming amount of case reports which highlight the prevalence of this problem. Please note we have no access to error report databases (see here) – these cases represent only some of those available via the internet – we have little doubt there are multiple more.
As is the nature of adverse events in healthcare they tend to be dispersed in time and place. This often starves us of the impetus required to put effective system measures in place.
We’ve only just started to collate this data, however one may already start to appreciate the magnitude of this issue.
Please help us put a stop to these avoidable adverse events: (read here)
Case Reports – Maintenance
Disconnection / ports left open
Other e.g. damage to central line
Case Reports – Removal
1. Patient not supine
No residual deficit
2. Central line insertion site not sealed sufficiently
Please note we have only just started to collate this date. We have little doubt there are hundreds of other individual case reports in journals which are not included above. These reports only represent a fraction of the true number of cases. We will continue to update this list.
Please help stop these avoidable deaths: click here.
Estimates of Frequency:
1. How many central lines are inserted per year?
2. What proportion of the central lines are complicated by air emboli?
3. What proportion of the air emboli result in death?
Awareness, Experience & Education
Survey: Only 31% of nurses (whose job description included removal of central lines) reported using all the recommended procedures. (see here)
Nurses more aware than doctos of risks of air embolism on CVC removal (see here)
Air embolism entirely preventable complication, but not widely known among practitioners (see here)
Are we missing too many cases? (see here)
Nurse Survey. In overall group comparison, few differences were found between nurses and physicians in terms of patient positioning at CVC insertion or removal. Nurses were more likely than physicians to request air-occlusive dressings after CVC removal (19 of 53 [36%] vs. 12 of 140 [9%]; p < .001), but there was no difference between nurses and physicians in awareness of VAE as the reason for choosing one patient position or dressing over another (29% vs. 39%, respectively). Critical care nurses with <=2 years of experience more often placed the patient in the supine or the Trendelenburg position for CVC removal than nurses with >2 years of experience (71% vs. 26%; p = .03).
Although most physicians (127, 91%) chose the Trendelenburg position for CVC insertion, only 42 physicians (30%) reported concern for VAE. On CVC removal, only 36 physicians (26%) cited concern for VAE. Some physicians (13, 9%) reported elevating the head of the bed during CVC removal, possibly increasing the risk of VAE. Awareness of VAE or its prevention did not correlate with the level of physician training, experience, or specialty. After the educational intervention, concern for and awareness of proper methods of prevention of VAE improved (p < .001). At 6-month follow-up, reported use of the Trendelenburg position continued, but concern cited for VAE had returned to baseline. (see here)
What is an air embolus and how do they occur?
An air embolus is basically air in blood vessels. They occur when there is an opening between a blood vessel and the atmosphere (or other source of air) and there is a pressure gradient allowing air to enter the blood vessel i.e. the pressure in the blood vessel is less than that in the atmosphere. Every time we breath in we create a negative pressure in our chest which sucks air into our lungs. The blood vessels in our chest are also subjected to this negative pressure. If there is an opening between blood vessels in the chest and the atmosphere air can open very rapidly. Enough air can enter a central line in a matter of seconds to cause a fatal air embolus.
Central line related air emboli tend to occur from:
1. Accidental line disconnections.
2. During line removal if patients are sat upright.
3. On insertion of larger lines (e.g. Tunnelled Vas Caths) with patients breathing spontaneously, generating negative intrathoracic pressure.
What should we do when a patient requires their central line to be removed but they can’t lie flat?
Patients who can’t lie flat or have other risk factors have an increased propensity for air embolism on central line removal. In these circumstances there needs to be an escalation of procedure:
Assess patient for increased risk of air embolism before removal of the CVC. Risks include:
– Respiratory compromise (can generate a large negative intrathoracic pressure increasing risk and rate of air entrainment. Consider if the patient would benefit from non-invasive ventilation support around the time of central line removal)
– Intravascular depletion (which can lead to a greater negative intravascular pressure, increasing the risk and rate or air entrainment)
– Inability to lie flat for an extended period (if unable to lie flat may create a pressure gradient that favours movement of air into the circulation)
– Low body mass index (smaller tract between the atmosphere and the vessel)
If the patient is unable to tolerate lying in the supine position or are considered high risk, the following should occur:
– Do not remove the CVAD in the first instance
– Contact an experienced critical care medical officer to review and manage the patient
– Delay removal until the risks can be minimised (if possible)
– Vascular access nurse (or experienced nurse) remove central line when appropriate
– Critical care medical officer in attendance
– Ensure alternative venous access already obtained
– Remove line in an adequate environment – monitored, with arrest trolley at hand
– Patient to remain monitored until satisfied risks of air embolism have abated
Beyond education and policy documents how else can we remind staff to remove central lines supine?
Despite education and policies we note that many medical staff still believe that the correct position to remove central lines is with them sat upright:
This issue may be explainable through understanding how humans work in systems. Also all healthcare staff will have learnt first aid and that bleeding sites should be elevated above the level of the heart to reduce further bleeding – unfortunately when it comes to a central line sites this puts the patient at grave risk of an air embolus. Further removal of central lines may seem like a benign procedure – perhaps to some posing little risk beyond removing a peripheral cannula. Given central line air embolus error reports are siloed away in reporting systems many front line staff have not even heard of this issue.
The human factors diagram below neatly depicts that education and policy writing, interventions we have relied heavily on in healthcare are actually relatively inneffective when it comes to improving safety. To learn more about human factors please click on the resources link.
We are in the final stages of releasing an animation focused on a simple message:
‘REMOVE CENTRAL LINES SUPINE’
We have liased with several central line dressing manufacturers to develop dressings with the phrase ‘Remove Central Lines Supine’ ‘To avoid air emboli‘ imprinted on them as a point of care message to staff. Perhaps this is the best location to have a point of care message without interfering with the day to day management of the central line.
Please sign this petition (click here) which goes straight to staff working for the major sterile dressing manufacturers who can make this happen.
How can we stop those air emboli which occur from accidental central line disconnection?
Air can enter central lines accidentally left open to air in a matter of seconds causing intractable cardiac arrest. There have been numerous case reports of deaths from this mechanism – all are avoidable.
We do not need central lines or vascular attachments that open to air. We could effectively eliminate this risk by replacing them with those that do not.
We will continue to update information on suppliers as it becomes available.
Please note we have no financial interest with any of the products discussed on this website.
Bill Houghton National Product Manager – Business Development
Regional Health Care Group,
Mobile: +61 (0)426 227 207
Paul Williams – Director New Medical, Mobile: +61 (0)410 537746
Stopcock with moulded H-Port valves product 50.262H
TUTA Australia, Vesna Acevska, Phone: 1300 361 162
How might we reduce air emboli which occur during central line insertion?
The risk of air emboli on central line insertion may be reduced by ensuring the patient is in a head down position, and where appropriate using positive pressure ventilation (keeping the intrathoracic pressure greater than atmospheric pressure).
Tunnelled Vas Cath central lines appear to be at particular risk of air emboli on insertion.
Why hasn’t the magnitude of this issue been recognised before?
Many front line staff healthcare staff have not even heard of deaths occurring from Central Line Related Air Emboli:
Unfortunately the construct of error reporting systems worldwide leads to vital information being siloed away. Current error reporting systems lack transparency (see here).
Medical error has been reported as the third greatest cause of death in hospitals (see here). The risk of central line air emboli is only one of thousands of hazards. If we are to overcome these unnecessary risks we will have to change the way we manage healthcare safety (see here).