Objective The peripheral intravenous cannula/catheter (PIVC) is indispensable in modern healthcare today. Despite it being the most used of the vascular access devices, it is not without complication, in particular: insertion failure; and premature/post-insertion device failure. The aim of this PhD was to develop an understanding of PIVC failure; both insertion and post insertion so that a clinical decision rule to improve PIVC first-time insertion success (FTIS) and reduce post-insertion failure (PIF) is derived. Therefore, these intentions would improve the science of vascular access, promote better vessel health, and preserve veins from repeated needle insertions. In identifying FTIS rates in the Emergency Department (ED), risk factors for this phenomenon can be used to develop a clinical decision rule. Additionally, measuring the rate of post-insertion failure and identifying the cause of it will provide baseline and hypothesis-generating data to improve PIVC insertion and post-insertion practice. Design By firstly assessing the current quality of tools, clinical decision rules, and algorithms for PIVC insertion and their impact on FTIS, a precedent for the development for a two-phase study was established. Phase 1 included a prospective cohort study of PIVC FTIS rates in the ED setting in addition to identifying the rationale for removal of the ED PIVC using a retrospective medical chart review method. Phase 2 was a multicentre cohort study of PIVC insertions in a patient population presenting to ED, with follow-up observation of the PIVC in subsequent admissions to the hospital ward. Phase 1 Setting One ED in Western Australia. Sample A convenient sample identified a FTIS rate in ED patients requiring a PIVC and with complete data a logistic regression model of patient and clinical factors in addition to a combined model was developed. In an admitted cohort we attempted to identify the rationale for removal of these PIVCs. Data Collection Tool Information was gathered about patient factors and clinician factors. Patient factors included the following: body mass index classification; skin shade; and, vein characteristics such as site, size, and quality (visible/palpable). Clinician factors included: clinician role; years inserting PIVCs; and, estimation of confidence for FTIS. Additional data points included the rationale for insertion, and FTIS result (yes/no). Main Results A total 734 PIVCs insertions were included in the study. The first-time insertion success incidence was 86%. The ante cubital fossa (ACF) site accounted for over 50% of insertions. Multivariate logistic regression modeling to predict first-time insertion success for patient factors found: age <40 vs 80+ years OR 3.04 (95% CI, 1.05-8.83, p=0.041); emaciated vs normal patient size OR 0.05 (95% CI, 0.01-0.23, p=<0.001); having a visible vein OR 4.62 (95% CI, 2.17-9.86, p=<0.001); and, ACF vs forearm insertion site OR 2.79 (95% CI, 1.30-5.97, p=0.008) to be statistically significant. Statistically significant clinician factors predicting success were: higher number of prior cannulation procedures performed 101-800 vs 0-100 OR 4.25 (95% CI, 1.56-11.67, p=0.005), and increased clinician perception of the likelihood of a successful insertion OR 1.07 (95% CI, 1.05-1.08, p=<0.001). When patient and clinician factors were combined in a logistic regression model the following were statistically associated with first-time insertion success: emaciated vs normal OR 0.07 (95% CI, 0.02-0.34, p=0.001); visible vein/s OR 2.7 (95% CI 1.19-6.13, p=0.018); ACF vs forearm site OR 2.82 (95% CI, 1.28-6.24, p=0.01); higher number of prior PIVC procedures performed 101-800 vs 0-100 OR 5.5 (95% CI, 1.86-16.30, p=0.002); and increased clinician perceived likelihood of success OR 1.06 (95% CI, 1.04-1.07, p=<0.001). 131 patient charts were reviewed; 51% of charts had no recorded rationale for PIVC removal. Of those with an unknown rationale for removal, 37% had documented evidence of subsequent peripheral cannulae. The just in case/unused cannula prevalence was 16%. The study was stopped early due to the frequent lack of documentation on rationales for PIVC removal. Phase 2 Setting Two tertiary EDs in Western Australia. Sample A total of 1,337 PIVC insertions were inserted in 967 patients who presented to two EDs with follow up of 391 patients admitted. Data Collection Tool Information was gathered about patient factors and clinicians factors. Patient factors included the following: Australasian Triage Score (ATS); body mass index classification; skin shade; and vein characteristics such as site, size, and quality (visible/palpable). Clinician factors included: clinician role; years inserting PIVCs; and, pre procedural confidence to succeed with a FTIS. Additional data points included: the rationale for insertion and FTIS result (yes/no); the procedural technique, (specifically if an aseptic non touch technique (ANTT)/ key part protected (KPP) technique was used); and the rationale for removal and dwell time in the admitted patient. Product and technological points included the size of PIVC, if ultrasound was used and what infusates were administered. Main Results The FTIS rate was 71%, with 148 (14%) requiring a second attempt and 122 (12%) requiring three or more attempts. A small percentage (3%) had no accurate number of subsequent attempts. FTIS is related to the following multivariate patient factors: age (for every additional year) OR 0.99 (95% CI, 0.983-0.998, p=0.0097); target vein palpability OR 3.53 (95% CI, 1.64-7.60, p=0.0014). Multivariate clinician factors include: clinician with greater confidence (p<0.0001), and staff experience 301-1000 versus <301 OR 1.54 (95% CI, 1.02-2.34) >1000 vs <301, OR 2.07 (95% CI, 1.41-3.04, p=0.0011). The all model has a sensitivity of 74.60%, specificity of 57.69%, positive predictive value of 82.87%, and negative predictive value of 44.85%. In the sample of admitted patients (n=391) the rate of PIF was 30% (n=118). Mean PIVC dwell-time was 37.52 hours (<1hr-166hrs). Infiltration and occlusion were the most common causes of PIF 47% (n=45). Univariate and multivariate Cox proportional hazards regression modeling of the time to PIVC PIF identified the following significant factors: Australian Triage Score (ATS) 1-2 compared to 3, 4, or 5, HR 2.04, (95% CI, 1.39-3.01, p=0.0003); Ultrasound guided (USG) PIVCs, HR 6.52, (95% CI, 2.11-20.10, p=0.0011). When an ANTT/KPP approach is used, the PIVC is significantly more likely to have longer survival than PIVCs without HR 0.63, (95% CI, 0.42-0.96, p=0.0326). Conclusion Peripheral intravenous catheter insertion success could be improved if performed by clinicians with greater procedural experience and increased perception of the likelihood of success. Some patient factors predict PIVC FTIS: “normal” body weight, visible vein/s, and cubital fossa placement. Venepuncture may be a cheaper alternative for others if intravenous therapy is not imperative. Furthermore, retrospective chart audits will continue to be a futile method to investigate PIVC failure until the quality of documentation for insertion and removal are improved. A specific vascular access device registry or clinical form that includes rationales for insertion and removal should be implemented to allow national quality and safety standards that accurately measure PIVC complications. These results should be interpreted carefully by respecting the primary outcome FTIS. Successful ED PIVC insertion relies on a variety of factors, but identifying risk factors described here will achieve greater FTIS when two patient variables (younger age and vein palpability), and two clinician variables (greater confidence and having at least inserted over 300 PIVCs) coexist. The primary objective for the clinicians and healthcare service providers is to consider these RF to obtain FTIS. Procedural competence could be amassed in patients with better vein visibility and palpability. In this way, the number of unnecessary insertion attempts in addition to repeat insertion attempts is hopefully reduced. PIF remains at an unacceptable standard in both traditional and ultrasound inserted PIVCs. PIVCs at the highest risk of PIF include: those inserted without an ANTT/KPP approach; those with a USGPIVC insertion; and, in the ED patient category ATS 1-2.