Introduction   

The peripheral intravenous catheter/cannula (PIVC) is the most pervasive vascular access device used in healthcare worldwide.1 In the emergency department (ED), it facilitates access to the circulatory system for intravenous fluid and medicines, for diagnostic blood sampling and for use in diagnostic imaging.

A recent systematic scoping review on improving first-time insertion success (FTIS) decision approaches identified the lack of a robust clinical decision tool to guide clinicians inserting PIVCs in adults.2 Despite the clinical utility and ubiquity of PIVC insertion in EDs, obtaining PIVC FTIS is a clinical problem which appears to be largely ignored. It is important to highlight that PIVC insertion failure has been described as painful,3 with repeated punctures likely increasing the risk of infection,4 5 all of which can negatively impact on quality and safety of healthcare as well as the patient experience.

FTIS is influenced by patient and clinician factors. Patient characteristics reported in the literature which compromise FTIS include: few visible and or palpable veins; diabetes or cancer diagnoses and emaciated and obese weight.2 Specific to the ED, Sebbane et al proposed extremes of body mass index (BMI) and absence of vein visibility and palpability to be independently associated with insertion difficulty.6 In contrast, Fields et al reported medical conditions such as diabetes, intravenous drug abuse and sickle cell disease to be significantly associated with repeat attempts.7 Clinician characteristics associated with FTIS include: greater years of experience; numerical quantity of PIVC insertions performed; professional roles such as specialist vascular access teams, specialist nurses or medical consultants.8–10

In the absence of a visible, palpable vein, the knowledge of landmark strategies becomes important. However, this may be unsafe given the normal variation in distribution of veins.11 Reported ED FTIS rates using traditional attempts (ie, landmark/palpation guided insertion) range from 74% to 86%.6 9 10 Failure to obtain FTIS may lead to cannulation of higher risk central, external jugular or lower limb veins, and ultrasound-guided peripheral intravenous catheter (USGPIVC) is a modality aimed to avoid this.12 It is less than encouraging to know that FTIS rates of just 69% are obtained when USGPIVC methods are used in the ED.12 This suggests that solving a problem with technology may not address the root cause of it.

Published vascular access frameworks are intended to assist with vascular access device selection13 14 and the insertion process but lack decision-making rules specific to achieving FTIS. Very few clinical studies illustrate the efficacy of such decision rules.2 One recent study by van Loon et al described an adult difficult intravenous access scale (A-DIVA).15 Their work was based on risk factors for failed FTIS in patients presenting for surgery. A notable limitation of the A-DIVA is that all the modifiable factors associated with FTIS were patient related.15 In the ED, repeated attempts contribute to inefficiency and impact on the clinician and the patient, and hinder patient flow through the department. Consequently, after two failed attempts, patients are referred to as difficult intravenous access (DIVA)2 with some hospitals employing a dedicated team approach to manage this clinical problem.16 Obtaining FTIS must be considered a clinical priority and we aimed to identify a broad range of clinical factors associated with FTIS rates in EDs (patient, clinician and product).

Methods

We published the protocol and methods of how we intended to report risk factors for peripheral intravenous FTIS in the ED.17 Our study is registered with the Australian and New Zealand Trials Registry (ANZCTRN12615000588594). We used the Strengthening the Reporting of Observational Studies in Epidemiology checklist to assist the reporting our results.18

Results

Comparison of multivariate models

Figure 1 displays the ROC curves for each of the multivariate models, while table 3 contains the AUC for each of the multivariate models, as well as p values from the pairwise comparison of each model’s AUC. The statistical model considering all factors (AUC=0.71) has significantly greater discriminative ability for identifying FTIS factors than each of the models that contain only patient factors (AUC=0.67, p=0.0178), clinician factors (AUC=0.68, p=0.0209) or product and technology factors (AUC=0.59, p<0.0001). The model considering all factors had a sensitivity of 74.26%, specificity of 57.69%, a positive predictive value of 82.87% and a negative predictive value of 44.85%.

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Figure 1

Receiver operating characteristic curves for each of the multivariate models. AUC, area under the curve.

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Table 3

AUC for each of the different multivariate models, as well as p values from the pairwise comparison of each model’s AUC

Discussion

The findings of this study demonstrate that FTIS is a clinically significant issue that needs improvement with 27% of patients requiring one or many subsequent attempts. We identified both patient factors (eg, non-palpable vein, being elderly) and clinician factors (eg, number of insertions and pre-insertion confidence) independently associated with reduced and increased odds of success, respectively. Ultrasound-guided insertions predicted a failure of FTIS; however, this is an expected finding as these devices were used by clinicians on patients as a last resort for locating a peripheral vein, or where the clinician had already failed with previous insertion attempts. Although other studies have suggested that extremes of BMI are independently associated with insertion failure,6 9 our results do not support this viewpoint. Surprisingly, we found BMI to be non-significant in any multivariate analysis, which is in agreement with a previous study identifying that failure was not independently associated with BMI.10

Traditional palpation/landmark-based approaches using 32 mm length PIVC for insertion were favoured first by clinicians in both study sites. Furthermore, ultrasound-guided insertion using 48 mm length PIVCs were generally only considered when multiple failures had already occurred. That 27% of patients in our study were subjected to a repeat PIVC insertion is 13% more than our previous inserter-reported study in one of the same hospitals, indicating that our self-report method led to a large degree of under-reporting.9 If we assume that DIVA patients are >2 failed attempts, then approximately 12% of the population recruited in our study could be categorised as such. Recently, van Loon et al 15 identified that patients with a history of first-time insertion failure had a fourfold increase of failure with future attempts. Accepting this, are we perhaps too lenient with current policy initiatives that require escalation after two failed attempts and perhaps healthcare organisations should advocate for decisions after one failed attempt to escalate to more advanced techniques? It is common that after >2 failed attempts ultrasound-guided insertion approach is used12 and yet recent systematic reviews and meta-analyses on ultrasound and other vein-locating technologies do not overwhelmingly acknowledge their clinical advantage when compared with traditional techniques.23 24 Conceivably, this is owing to an additional skill and expertise that needs to be well developed before optimum insertion success frequency is obtained.

As to what clinician role is paired with this clinical expertise is interesting given the variety of clinicians who perform PIVC insertion. Our descriptive results from one site showed that phlebotomists, performing PIVC procedures had similar success to ultrasound trained consultant emergency physicians and better success than consultant emergency physicians without additional ultrasound training. Typically, consultants with additional ultrasound training will likely be called for DIVA cases, given their seniority and advanced skills with ultrasound techniques. The economic cost implications are clear as phlebotomists are paid less than nurses and doctors, yet have a better FTIS rate. One rationale is that the particular clinical procedure they provide is not affected by multiple competing clinical tasks; such as patient assessment and only includes venesection and PIVC insertion. Nurses performing this skill consistently has also been attributed to very high FTIS rates 98%–99%.25 26 In our multivariate logistic regression, more experienced inserters had significantly better FTIS rates than less experienced staff. While some argue that all medical personnel should be skilled in PIVC insertion, a more nuanced approach based on skill and experience may be needed to improve outcomes. When clinicians are unable to visualise and palpate a visible vein for potential PIVC insertion this should prompt the assistance of a more skilled and proficient clinician. Additionally, the competent use of ultrasound by a skilled and proficient clinician would better inform an assessment that would lead to successful insertion.

Although these findings are preliminary, they provide evidence to assist with the derivation of a clinical prediction score, once validated on a separate population of patients and clinicians. This is particularly important as a limitation of the convenience sample used is the potential for selection bias related to clinicians observed and patients requiring a PIVC. While we used accepted statistical approaches, that is, calibration and internal validation, our AUC is fair and lower than we had hoped in terms of the patient and clinician models’ discriminative ability to predict those who are likely to have a FTIS. No scoring tool or rule will be able to precisely predict every PIVC insertion success15; however, we did include the clinician variable in our modelling, as clinicians insert the PIVC into a vein which they independently select.

We acknowledge that we may have accounted for multiple PIVCs inserted by the same individual clinicians and that lack of variation could explain improved FTIS. Therefore, a limitation of this study is that a unique clinician identifier was not collected and so clustering of patients to specific clinicians could not be included in the modelling. However, clinician experience and role were included to adjust for differences between staff. In future research, individual clinician factors could include in-depth detail on the level and description of vascular access education, and account for non-independence of measures.

Additionally, our results are limited by an underrepresentation of dark-skinned patients and perhaps DIVA patients. The DIVA patient responses were low, as we could not ask all patients if they had a DIVA history. Additionally, it is likely other factors would confound this variable and perhaps better classifications are needed.2 As a cohort study, we can report statistical associations between patient, clinician, products and technology factors with FTIS but cannot definitively conclude cause and effect relationships. Randomised studies will be needed to confirm if a clinical decision rule applying these results to guide insertions leads to improvements in FTIS. How the transfer of a skill to those less practiced or with less recent practice is a local matter for individual EDs and their clinical simulation centres. The skills and knowledge associated with PIVC insertion are not profession dependent and a team approach should be encouraged to the benefit of both patient and clinician, but would require changes to current workforce models and institutional workflows. The personal and financial cost of repeated insertions, and the impact on patients and clinicians should be a target for future quality improvements projects to address. In conclusion, a clinical decision rule that matches patients who have no palpable veins and are older, with clinicians who have greater confidence and experience will likely yield greater FTIS.