Non-Luer connectors: are we nearly there yet?

Accidental epidural catheter removal rates and strength required for disconnection: a retrospective cohort and laboratory study

Background

Epidural catheters are associated with certain risks such as accidental epidural catheter removal, including dislodgement and disconnection. Globally, neuraxial connector designs were revised in 2016 to provide new standardization aimed at decreasing the frequency of misconnections during the administration of medications. However, no studies have investigated accidental epidural catheter removal after the revised standardization. This study aimed to examine differences in dislodgement and disconnection rates associated with different catheter connector types, and to investigate the linear tensile strength required to induce disconnection.

Methods

This retrospective cohort study included adult patients who underwent elective surgery and received patient-controlled epidural analgesia. Patients were divided into groups according to the type of catheter connection used: old standard, new standard, and new standard with taping groups. Furthermore, we prepared 60 sets of epidural catheters and connectors comprising 20 sets for each of the old, new, and taping groups, and used a digital tension meter to measure the maximum tensile strength required to induce disconnection.

Results

This clinical study involved 360, 182, and 378 patients in the old, new, and taping groups, respectively. Dislodgement rates did not differ statistically among the three groups, while there was a significant difference in disconnection rates. Propensity score matching analysis for disconnection rates showed no difference between the old and new groups (2.8% vs. 4.5%, p = 0.574), while the new group had higher rates than the taping group (6.5% vs. 0%, p = 0.002). This laboratory study identified that a tensile strength of 12.41 N, 12.06 N, and 19.65 N was required for disconnection in the old, new, and taping groups, respectively, and revealed no significant difference between the new and old groups (p = 0.823), but indicated a significant difference between the new and taping groups (p < 0.001).

Conclusions

This clinical study suggested that dislodgement rates did not change among the three groups. Both clinical and laboratory studies revealed that disconnection rates did not change between the old and new connectors. Moreover, as a strategy to prevent accidents, taping the connecting points of the catheter connectors led to an increase in the tensile strength required for disconnection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01728-z.

Neuraxial and peripheral misconnection events leading to wrong-route medication errors: a comprehensive literature review

We conducted a search of the literature to identify case reports of neuraxial and peripheral nervous system misconnection events leading to wrong-route medication errors. This narrative review covers a 20-year period (1999-2019; English-language publications and abstracts) and included the published medical literature (PubMed and Embase) and public access documents. Seventy-two documents representing 133 case studies and 42 unique drugs were determined relevant. The most commonly reported event involved administering an epidural medication by an intravenous line (29.2% of events); a similar proportion of events (27.7%) involved administering an intravenous medication by an epidural line. Medication intended for intravenous administration, but delivered intrathecally, accounted for 25.4% of events. In the most serious cases, outcomes were directly related to the toxicity of the drug that was unintentionally administered. Patient deaths were reported due to the erroneous administration of chemotherapies (n=16), muscle relaxants (n=4), local anesthetics (n=4), opioids (n=1), and antifibrinolytics (n=1). Severe outcomes, including paraplegia, paraparesis, spinal cord injury, and seizures were reported with the following medications: vincristine, gadolinium, diatrizoate meglumine, doxorubicin, mercurochrome, paracetamol, and potassium chloride. These case reports confirm that misconnection events leading to wrong-route errors can occur and may cause serious injury. This comprehensive characterization of events was conducted to better inform clinicians and policymakers, and to describe an emergent strategy designed to mitigate patient risk.

Strength of commonly used spinal needles: the ability to deform and resist deformation

We investigated the strength of commonly used spinal needles in relation to the amount of deformation, and registered forces during standardised testing. We investigated differences between manufacturers for the same length and gauge of Luer and non-Luer needles, and examined the effect of the internal stylet in terms of needle strength. A specialised rig was designed to perform the testing in both the horizontal and axial plane, reflecting common industrial tests and clinical use. Needles from four commonly used manufacturers were used (Vygon, Becton Dickinson, B Braun, and Pajunk). Needles of 25 G and 27 G were tested in 90-mm and 120-mm lengths. We found significant differences in terms of the size of final deformation and 'toughness'/resistance to deformation between needles of different brands. There were also significant differences between horizontal tests conducted as an industry standard and our own axial test. This may have bearing on clinical use in terms of the incidence of bending and breakage. The presence of the internal stylet resulted in significantly greater toughness in many needles, but had little effect on the degree of deformation. Comparison of Luer and non-Luer needles of the same brand and size showed few significant differences in strength. This result is reassuring, given the imminent change from Luer to non-Luer needles that is to occur in the UK.

How do health service professionals consider human factors when purchasing interactive medical devices? A qualitative interview study

We present findings of a UK study into how those involved in purchasing interactive medical devices go about evaluating usability, the challenges that arise, and opportunities for improvement. The study focused on procurement of infusion devices because these are used by various professionals across healthcare. A semi-structured interview study was carried out involving a range of stakeholders (20 in total) involved in or impacted by medical device procurement. Data was analysed using thematic analysis, a qualitative method designed to support the identification, analysis and reporting of patterns. In principle, health service purchasing was found to accommodate consideration of equipment usability. In practice, the evaluation process was driven primarily by engineering standards; assessment of local needs did not accommodate substantive assessment of usability; and choice was limited by the availability of equipment on the marketplace. We discuss ways in which purchasing could be improved through techniques that account for social circumstances.