Study on the microbial safety of an infusion set for contrast-enhanced imaging. Invest Radiol. 2012;47:247-251. [PMID: 22353856 DOI: 10.1097/rli.0b013e31823c0f87]

Bacterial contamination and greenhouse gas emissions: A randomised study of reuse versus single-use of infusion-set components for intravenous anaesthesia

BACKGROUND

Reusing anaesthesia infusion-set components may reduce the climate impact from plastic waste and discarded medications. Infusion-set contents can be shielded from patient contact by single use of an infusion line fitted with dual antireflux valves, preventing retrograde entry of microorganisms, and eliminating the risk for patient-to-patient cross-contamination. However, infusion-set contamination from compromised aseptic handling could affect quality of care.

INTERVENTIONS

To determine the prevalence of infusion-set bacterial contamination and compare the climate effects, we randomised operating rooms scheduled for total intravenous anaesthesia to handle procedures by infusion-set reuse or single-use. Both methods used dual single-use antireflux valves.

OUTCOMES

The primary outcome was infusion-set bacterial contamination assessed by aerobic culture of infusion-set fluid collected after each procedure. The secondary outcome was CO 2 emissions (CO 2 -eq) estimated by life cycle assessment of component and medication use. To assess feasibility of detecting an inter-method difference in bacterial contamination, an interim analysis was planned after including at least 150 procedures per group.

RESULTS

After allocating 54 operating rooms per method, 189 and 159 procedures of reuse and single use were included. Reuse permitted a median of three procedures per infusion set (range 1 to 8). Positive cultures occurred in two procedures per method [mean (95% CI)]; prevalence 1.15% (0.03 to 2.27); relative risk of reuse versus single use 0.84 (0.12 to 5.93), P  = 0.861. As prespecified, inclusion was stopped due to futility. The median (95% CI) per-procedure climate emissions were 0.43 (0.41 to 0.47) and 1.39 (1.37 to 1.40) kg CO 2 -eq for reuse and single-use respectively; difference -0.96 (-0.99 to -0.93), P  < 0.0005. The main sources for climate emissions were production of infusion-set components and waste handling.

CONCLUSIONS

We conclude that the prevalence of bacterial contamination was low for both methods. A much larger study would be needed to detect an inter-method difference. Reuse of infusion-set components allowed significantly reduced intravenous anaesthesia climate emissions.

Infection prevention and control in the medical imaging environment: a scoping review

Infection prevention and control (IPC) practices are key to preventing and controlling the spread of pathogens in medical imaging departments (MIDs). The objective of this scoping review was to synthesise information about current research in MID regarding IPC and to use the Systems Engineering Initiative for Patient Safety (SEIPS) model to identify the work system factors ('persons', 'organisation', 'tools and technology', 'tasks' and 'environment') influencing the practice of IPC, in order to better understand challenges and facilitators that affect IPC in MID. Predefined search terms and medical subject headings relating to IPC in the medical imaging setting were used to search 3 databases. A total of 46 publications met the inclusion criteria, which combined, encompassed all five SEIPS domains influencing IPC. The literature supports the interrelated nature of the five SEIPS domains, and influence to one another. Hand hygiene was a major focus of publications. Mechanisms of infection in contrast-enhanced computed tomography were most reported, with human error, lack of education, and issues associated with devices and processes mechanisms found to influence IPC breaches. A systems approach, such as the SEIPS model, is useful for understanding barriers and hence opportunities for improvement of IPC in the medical imaging setting. Future studies should address individuals' decision-making processes in the medical imaging setting, and a greater focus should be placed into the procedural steps, education and tools used for contrast media administration. CRITICAL RELEVANCE STATEMENT: A systems approach, such as the Systems Engineering Initiative for Patient Safety model, is useful for understanding barriers and hence opportunities for improvement of IPC in the medical imaging setting. KEY POINTS: 1. IPC in the medical imaging setting would benefit from a systems approach. 2. The role of education and monitoring of IPC compliance requires further research. 3. Geographical location is a key variable in IPC research in medical imaging.

In Vitro Investigation of an Electrically Actuated Antireflux Valve for a Multiuse Contrast Agent Injection System

OBJECTIVE. The purpose of this study was to determine the capability of a newly developed antireflux valve for a multiuse contrast agent injection system. MATERIALS AND METHODS. Multiuse contrast agent injection systems require an antireflux valve to eliminate the risk of cross-patient blood contamination. An electrically actuated antireflux valve developed for this purpose can control risk of contamination because it is under forced control and surveillance. In this study, the injection system was connected to a pulsatile circulation system that reproduced an aortic flow environment in vitro. The transvalvular pressure difference was measured, and flow dynamics during valve opening and closing were visualized by high-speed flow visualization. A total of 30 injection conditions were tested, which included two catheters (6- and 2-French diameter), five contrast agent concentrations (100%, 90%, 50%, 10%, and 0%), and a wide range of flow rates (0.1-25.0 mL/s). RESULTS. The transvalvular pressure difference and flow dynamics during valve opening and closing were characterized. Just before valve opening, a minimum transvalvular pressure difference of 0.20 MPa (1500 mm Hg) was confirmed. The positive pressure difference prevented regurgitation during valve opening. During valve closing, the front of the backflow was monitored continuously, and we confirmed that the front failed to reach the valve before complete closure. CONCLUSION. This study provided proof of concept for an electrically actuated antireflux valve to be used in a multiuse contrast agent injection system.

Biosafety of Non-Return Valves for Infusion Systems in Radiology

Cross-infection in contrast injectors is still a subject under discussion with little understanding. This study evaluated the biosafety of non-return valves (NRVs). Initially, the maximum pressure during backflow of intact and disrupted flexible diaphragms (FDs) from NRVs, as well as the functionality of connectors with NRVs were verified. The performance of air columns interposed by water in connectors with NRVs was analyzed, and the diffusion distance of crystal violet through connectors with NRVs was measured. The efficacy of NRVs as a barrier to bacterial contamination from backflow was evaluated. Finally, a clinical study of bacteriological contamination from syringes was conducted. There were differences among the maximum tolerated pressure by intact and disrupted FDs. Disrupted FDs showed no failures in the functionality of connectors with NRVs based on the lack of air bubbles released. Air columns could move through connectors with NRVs with intact and disrupted FDs. The longest diffusion distance of crystal violet was 6 cm of connector length, and NRVs showed efficacy as a barrier to bacterial contamination. In the clinical study, there was no bacterial growth in any of the evaluated samples. In conclusion, biosafety depends on the functionality of NRVs as well as proper practical clinical performance.

Cost-Minimization Analysis of Multidose and Single-Dose Packaging of Contrast Media for Contrast-Enhanced CT: Results From Real-World Data in China

OBJECTIVE. Utilization and waste in diagnostic imaging have substantially increased worldwide. The purpose of this study was to highlight the utilization of contrast material and cost savings resulting from implementation of a multidose bulk IV contrast delivery system. MATERIALS AND METHODS. An observational study was conducted in October-November 2018 in eight hospitals in eight provinces in China. Contrast media specifications were 100-mL single-use IV contrast vials and 200-mL and 500-mL bulk packaging. Linear regression analysis was performed to identify the factors influencing contrast media use. Cost-minimization and sensitivity analyses were performed from patient and payer perspectives. RESULTS. A total of 1032 patients, some of whom underwent more than one CT examination, were enrolled in this study (100-mL package, 776 CT examinations; 200-mL package, 382 CT examinations). The mean injected volume of contrast medium was 75.46 mL. Number of scanned body parts, specification of amount of contrast medium (0, 100 mL; 1, 200 mL), whether the examination was CT angiography (CTA) (0, not CTA; 1, CTA), and patient weight all had a positive impact on the injected volume of contrast medium (p < 0.001 for all variables). Implementation of a multidose bulk IV contrast delivery system combined with different reimbursement units resulted in substantial waste reduction, estimated at US$5.59-6.04 per contrast-enhanced CT examination from the payer perspective, US$12.84-14.66 per examination from the patient perspective, and a total reduction of US$18.29-20.70 per examination. CONCLUSION. Use of multidose packaging of contrast media combined with reimbursement units for patients undergoing IV contrast-enhanced CT was found to be cost saving compared with use of single-dose packaging.

An overview of translational (radio)pharmaceutical research related to certain oncological and non-oncological applications

Translational medicine pursues the conversion of scientific discovery into human health improvement. It aims to establish strategies for diagnosis and treatment of diseases. Cancer treatment is difficult. Radio-pharmaceutical research has played an important role in multiple disciplines, particularly in translational oncology. Based on the natural phenomenon of necrosis avidity, OncoCiDia has emerged as a novel generic approach for treating solid malignancies. Under this systemic dual targeting strategy, a vascular disrupting agent first selectively causes massive tumor necrosis that is followed by iodine-131 labeled-hypericin (¹²³I-Hyp), a necrosis-avid compound that kills the residual cancer cells by crossfire effect of beta radiation. In this review, by emphasizing the potential clinical applicability of OncoCiDia, we summarize our research activities including optimization of radioiodinated hypericin Hyp preparations and recent studies on the biodistribution, dosimetry, pharmacokinetic and, chemical and radiochemical toxicities of the preparations. Myocardial infarction is a global health problem. Although cardiac scintigraphy using radioactive perfusion tracers is used in the assessment of myocardial viability, searching for diagnostic imaging agents with authentic necrosis avidity is pursued. Therefore, a comparative study on the biological profiles of the necrosis avid ¹²³I-Hyp and the commercially available ^99mTc-Sestamibi was conducted and the results are demonstrated. Cholelithiasis or gallstone disease may cause gallbladder inflammation, infection and other severe complications. While studying the mechanisms underlying the necrosis avidity of Hyp and derivatives, their naturally occurring fluorophore property was exploited for targeting cholesterol as a main component of gallstones. The usefulness of Hyp as an optical imaging agent for cholelithiasis was studied and the results are presented. Multiple uses of automatic contrast injectors may reduce costs and save resources. However, cross-contaminations with blood-borne pathogens of infectious diseases may occur. We developed a radioactive method for safety evaluation of a new replaceable patient-delivery system. By mimicking pathogens with a radiotracer, we assessed the feasibility of using the system repeatedly without septic risks. This overview is deemed to be interesting to those involved in the related fields for translational research.