Bouquet, M. | Search bioRxiv

bioRxiv2022

Design, development, and preliminary assessment of a novel peripheral intravenous catheter aimed at reducing early failure rates

BackgroundPeripheral intravenous catheters (PIVCs) are the most commonly used invasive medical device, yet despite best efforts by end-users, PIVCs experience unacceptably high early failure rates. We aimed to design a new PIVC that reduces the early failure rate of in-dwelling PIVCs and we conducted preliminary tests to assess its efficacy and safety in a large animal model of intravenous access. MethodsWe used computer-aided design and simulation to create a PIVC with a ramped tip geometry, which directs the infused fluid away from the vein wall; we called the design the FloRamp. We created FloRamp prototypes (test device) and tested them against a market-leading device (BD Insyte; control device) in a highly-controlled setting with five insertion sites per device in four pigs. We measured resistance to infusion and visual infusion phlebitis (VIP) every six hours and terminated the experiment at 48 hours. Veins were harvested for histology and seven pathological markers were assessed. ResultsComputer simulations showed that the optimum FloRamp tip reduced maximum endothelial shear stress by 60%, from 12.7Pa to 5.1Pa, compared to a typical PIVC tip, and improved the infusion dynamics of saline in the blood stream. In the animal study, we found that 2/5 of the control devices were occluded after 24 hours, whereas all test devices remained patent and functional. The FloRamp created less resistance to infusion (0.73{+/-}0.81 vs 0.47{+/-}0.50, p=0.06) and lower VIP scores (0.60{+/-}0.93 vs 0.31{+/-}0.70, p=0.09) that the control device, although neither findings were significantly different. Histopathology revealed that 5/7 of the assessed markers were lower in veins with the FloRamp. ConclusionsAs PIVCs are used in almost every hospitalized patient, there is an urgent need to reduce failure rates. Herein we report preliminary assessment of a novel PIVC design, which could be advantageous in clinical settings through decreased device occlusion.

bioengineering↗

bioRxiv2020

Characterising pre-clinical sub-phenotypic models of Acute Respiratory Distress Syndrome: an experimental ovine study.

The Acute Respiratory Distress Syndrome (ARDS) describes a heterogenous population of patients with acute severe respiratory failure. However, contemporary advances have begun to identify distinct sub-phenotypes that exist within its broader envelope. These sub-phenotypes have varied outcomes and respond differently to several previously studied interventions. A more precise understanding of their pathobiology and an ability to prospectively identify them, may allow for the development of precision therapies in ARDS. Historically, animal models have played a key role in translational research, although few studies have so far assessed either the ability of animal models to replicate these sub-phenotypes or investigated the presence of sub-phenotypes within animal models. Here, in three ovine models of ARDS, using combinations of oleic acid and intravenous, or intratracheal lipopolysaccharide, we demonstrate the presence of sub-phenotypes which qualitatively resemble those found in clinical cohorts. Principal Components Analysis and partitional clustering reveal two clusters, differentiated by markers of shock, inflammation, and lung injury. This study provides the first preliminary evidence of ARDS phenotypes in pre-clinical models and develops a methodology for investigating this phenomenon in future studies.

physiology↗