Originally Published MDT October 2009
DESIGN
Safer Arterial Access
R. Santhirapala, J.J. Carter and P.J. Young
Queen Elizabeth Hospital, Kings Lynn, UK
Queen Elizabeth Hospital, Kings Lynn, UK
Intra-arterial injection of drugs intended for intravenous delivery is a frequent and potentially devastating consequence of placing an arterial line in a patient. A system is described here that prevents this complication from occurring and its use is advocated in intensive care and operating theatre settings.
Current dangers
Arterial cannulation for the purposes of beat-to-beat blood pressure monitoring and blood sampling is an increasingly common procedure. The current standard equipment consists of an arterial cannula connected to a continuous flush system (Figure 1). The system has one or two three-way taps that allow the sampling of arterial blood. It provides no impediment to intra-arterial injection. In addition, there is a risk of blood loss secondary to inadvertently leaving the three-way tap open to the patient and air. Because there is no requirement for intra-arterial injection of substances, it is clear that preventing this process is a fundamental step forward in patient safety.
Accidental intra-arterial injection of drugs that are intended for the intravenous route is a frequently reported complication in medical practice. Although the pathophysiology is still not clearly understood, the spectrum of complications are well documented, ranging from transient pain on injection to serious sloughing of skin and gangrene of the affected limb.1–6 Even when there is no actual tissue loss, long term functional and neurological limb deficits still occur.1 The consequences once tissue loss occurs can lead to amputation. The physical effects lead to an extended rehabilitation programme and follow up. It is important to recognise that together with the physical disabilities for the patient there are profound psychological consequences. In rare circumstances death has been reported as an outcome of inadvertent intra-arterial injection.
The complications of intra-arterial drug delivery depend on the drug that is injected. Medications that are commonly used in the theatre and the critical care setting, primarily the benzodiazepines and barbiturates, often result in serious consequences. In addition, patients requiring arterial line placement tend to be critically ill and may have multiple infusions running, all using the same luer lock connections as the current arterial lines. Hence, the risk of error and inadvertent intra-arterial injection is constantly present.
The risk is significant enough to draw much research interest. However, there are no definitive studies suggesting its incidence and it is likely that it remains a significantly under reported phenomenon. There has been much focus on the treatment of this devastating complication, but little on its prevention. Finding a preventative measure has obvious benefits particularly because the outcomes, even following prompt treatment, are variable.
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Figure 1: Three-way tap on current arterial line system.
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Figure 2: Noninjectable connector modified three-way tap.
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This article describes a simple modification that can be added as an integral part of future arterial line systems, or as an adaptor to be added to current systems, which will prevent these complications.
The noninjectable connector
The three-way tap (Figure 2) that is currently part of the arterial flush system has a female luer connector that allows connection of a male luer, usually for blood sampling in the clinical setting. There is no barrier to the administration of any drug or air via this side port. The only things that prevent clinicians from injecting into these lines are vigilance, combined with the fact that the lines are often coloured red and labelled to signify that they are intra-arterial. The significant numbers of reports of problems relating to this issue prove that this is insufficient.
A modification of the three-way tap (patent pending), consisting of a sampling port that would contain a one-way valve to allow only aspiration, prevents inadvertent arterial injection (Figure 3). In addition, if a luer slip connector was placed at this aspiration port, exsanguination secondary to the three-way tap being left open to the patient would be eliminated. The luer slip connector would allow needleless access to the sampling port with a male luer connector whilst preventing backflow through the sampling port when the syringe is removed.
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Figure 3: Safety connector.
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Figure 4: Noninjectable connector prototype.
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A survey of nursing and medical staff on an intensive care unit found there was no significant difference in the time taken to sample using the prototype of the new noninjectable connector.7 In addition, this connector allows sampling without the need for manipulation of the three-way tap. In the same survey, the clinical staff found sampling with the noninjectable connector to be easier than the conventional three-way system.
The search for solutions
It should not be possible to inadvertently inject drugs intended for intravenous delivery into an arterial cannula. Modification of the currently marketed arterial three-way tap or an adaptor that can be added to existing systems prevents this from being possible. Clinicians need the medical device industry to develop solutions that prevent these common and potentially devastating accidents from occurring. The prototype described here is being developed under the auspices of NHS Innovations, Health Enterprise East (www.hee.org.uk) and an industry partner is sought to advance it to a final clinical device.
References
1. S. Sen, E. Chini and M. Brown, “Complications After Unintentional Intra-arterial Injection of Drugs: Risks, Outcomes and Management Strategies,” Mayo Clinic Proceedings 80, 6, 783–795 (2005).
2. F. Zveibil and I. Monies-Chass, “Accidental Intra-Arterial Injection of Ketamine,” Anaesthesia, 31, 8, 1084–1085 (1976).
3. R. Michel and A. Adams, “Accidental Intra-Arterial Injection of Papavereturn During Anaesthesia,” Anaesthesia, 34, 5, 491–493 (1979).
4. D. Zideman and M. Morgan, “Inadvertent Intra-Arterial Injection of Flucloxacillin,” Anaesthesia, 36, 3, 296–298 (1981).
5. G. Kessell, “Leg Ischaemia in an Infant Following Accidental Intra-arterial Administration of Atracurium Treated with Caudal Anaesthesia,” Anaesthesia, 51, 12, 1154–1156 (1996).
6. C.R. McLean, K.S. Cheng and M.A. Clifton, “Fatal Case of Accidental Intra-arterial Phenytoin Injection,” European Journal of Vascular and Endovascular Surgery, 23, 4, 378–379 C (2002).
7. M. Rees and J. Dormandy, “Accidental Intra-Arterial Injection of Diazepam,” Br. Med. J., 281, 6235, 289–290 (26 July 1980).
8. K. Haiba et al., “Survey of a Non-injectable Connector for Intra-Arterial Systems,” Critical Care Medicine, 36, 12 Supp., Abstract 249 (2009).
Dr Ramai Santhirapala, *Dr Joseph J. Carter and Dr Peter J. Young Critical Care Unit, Queen Elizabeth Hospital, Gayton Road, Kings Lynn PE30 3RS, UK, tel. +44 1553 613 613, e-mail: josephcarter@nhs.net
*To whom all correspondence should be addressed
*To whom all correspondence should be addressed
Copyright ©2009 Medical Device Technology
