Patient Safety Tip of the Week


August 19, 2008

Arterial Line Issues





The UK NHS NPSA (National Patient Safety Agency) has issued a new rapid response report highlighting Problems with infusions and sampling from arterial lines. This consists of the problem description and recommendations and the supporting information. They found 84 incidents (two fatal) where the wrong infusion was attached to the arterial line and 76 incidents where faulty sampling technique occurred, sometimes leading to patient harm. A variety of solutions have been inadvertently infused through arterial lines, including concentrated glucose, potassium-containing solutions, MRI contrast agents, mannitol, insulin, antibiotics and others.


Some of the factors predisposing to such mishaps have included look-alike labeling and packaging of the intravenous infusion bags. In some cases, covering the infusion bags with pressure bags led to obscuration of the label. Errors may be especially prone to occur when patients are transported to other sites and nursing and medical staffs at the secondary sites are unfamiliar the lines. Inadequate labeling of the lines has also prevented their identification as being arterial lines.


The reports cite the statistic that over half of arterial blood gas analyses done on samples from critical care units may be clinically not justified.


Problems with sampling from arterial lines include cases where contamination from infusates has led to inappropriate therapy for patients. These have included cases in which false hyperglycemia led to fatal insulin overdosages. In others, failure to remove air bubbles from the samples have led to misinterpretation of results.


The recommended strategies to reduce risk are based on common sense, since no evidence base exists on such strategies. The recommended actions are:

        Sampling should only be done by competent, trained staff.

        Guidelines should include criteria for ABGs, sampling technique, monitoring and interpretation of results (including unexpected results).

        Clear identification of arterial lines (labeling or specifically marked lines).

        Any infusion attached to an arterial line must be prescribed and checked before administration.

        Staff should use only sodium chloride 0.9% to keep lines open.

        Labels should be clearly visible, even when pressure bags are used.


They also recommend asking some useful questions:

        Is there a clinical reason for inserting this line? Is it clearly marked as an arterial line?

        Do I need to take this sample?

        Do I know how to do this safely (eg. remove air from the sample)?

        Have I picked the right infusion bag? Did someone else check this?

        Can the label be seen, even if a pressure bag is used?

        Is the reading from the sample within the expected range? Could it have been contaminated?


Note that they have recommended saline rather than heparin flushes. They acknowledge that the evidence on the use of heparinised versus normal saline for arterial (and central venous) catheters is inconclusive (see our May 2008 Whats New in the Patient Safety World column in which we discussed the UK NPSAs alert Risks with Intravenous Heparin Flush Solutions.).



Speaking of heparin flushes, ISMP Canada has issued an alert on these with some excellent recommendations. They discuss the cases from Indiana, California, and Texas that we have previously discussed in our December 2007 and April 2008 Whats New in the Patient Safety World columns and our July 15, 2008 Patient Safety Tip of the Week. They have developed a toolkit being implemented in a group of Ontario hospitals currently. That toolkit is available to non-Ontario hospitals for $150 but they summarize the key recommendations in this alert. These include:

        Complete an audit of heparin storage areas throughout the hospital (including pharmacy) to identify high-risk situations.

        Assess current heparin utilization patterns and compare with best practices (eg. see the recent ACCP Antithrombotic and Thrombolytic Therapy, 8th Ed: ACCP Guidelines).

        Where possible, use alternative products or procedures for flushing and locking of access lines to limit exposure to unfractionated heparin.

        Consider low molecular weight heparin (LMWH) as an alternative to unfractionated heparin (UFH) where possible.

        Reduce the number of potentially high-risk situations where UFH is stored (eg. remove high-dose heparin products from floor stock, reduce availability of certain doses from patient care areas, develop protocols and guidelines for flushing lines, standardize products and consider one concentration hospital-wide, use single dose formats such as pre-filled syringes, and use clearcut labeling and physical separation of products in all areas, including the pharmacy)







UK NHS National Patient Safety Agency. Rapid Response Report. Problems with infusions and sampling from arterial lines. July 28, 2008



UK NHS National Patient Safety Agency. Rapid Response Report. Problems with infusions and sampling from arterial lines. July 28, 2008



UK NHS National Patient Safety Agency. Supporting Information for Rapid Response Report NPSA/2008/RRR06. Problems with infusions and sampling from arterial lines. July 28, 2008



ISMP Canada. Safety Bulletin. Enhancing Safety with Unfractionated Heparin:

A National and International Area of Focus. July 25, 2008










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