Central lines are essential for the care of many patients.
Unfortunately worldwide data indicate around one patient is dying every day from avoidable central line related air emboli.
We would appreciate your feedback on the numerous case series and reports presented below. (Please click on any links in red).
Many cases occur because of accidental line disconnections (this problem can be engineered out – see here). Many other cases occur when central lines are removed with patients sitting upright – staff should ensure patients are lying flat or slightly head down to central line removal.
Rarely a patient may not be able to lie flat for a sufficient period for line removal. In this case we recommend the following:
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)
– 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
This link provides some very useful information regarding central line management.
These are more than just statistics.
(Image above from CNN report)
Sufficient air can enter blood vessels rapidly, over 1 or 2 seconds, causing a cardiac arrest or cerebral air embolus which often leads to death.
The magnitude of this problem is not well known – adverse event being dispersed in place and time. Also the usual healthcare safety approach of education, alerts and policy writing doesn’t appear to have impacted on preventing this issue. In fact reports demonstrate the frequency of this adverse event is only increasing (see here).
We discuss how a human factors approach may significantly help in reducing adverse event frequency (see here).
Your feedback is greatly appreciated.
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.
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)