Efficacy evaluation of syringe pump developed for continuous drug infusion

Pressure-controlled microfluidics for automated single-molecule sample preparation

Sample preparation is a crucial step in single-molecule experiments and involves passivating the microfluidic sample chamber, immobilizing the molecules, and setting experimental buffer conditions. The efficiency of the experiment depends on the quality and speed of sample preparation, which is often performed manually and relies on the experience of the experimenter. This can result in inefficient use of single-molecule samples and time, especially for high-throughput applications. To address this, a pressure-controlled microfluidic system is proposed to automate single-molecule sample preparation. The hardware is based on microfluidic components from ElveFlow and is designed to be cost-effective and adaptable to various microscopy applications. The system includes a reservoir pressure adapter and a reservoir holder designed for additive manufacturing. Two flow chamber designs Ibidi µ-slide and Grace Bio-Labs HybriWell chamber are characterized, and the flow characteristics of the liquid at different volume flow rates V˙ are simulated using CFD-simulations and compared to experimental and theoretical values. The goal of this work is to establish a straightforward and robust system for single-molecule sample preparation that can increase the efficiency of experiments and reduce the bottleneck of manual sample preparation, particularly for high-throughput applications.

A Novel Artificial Pancreas: Energy Efficient Valveless Piezoelectric Actuated Closed-Loop Insulin Pump for T1DM

The objective of this work is to develop a closed-loop controlled insulin pump to keep the blood glucose level of Type 1 diabetes mellitus (T1DM) patients in the desired range. In contrast to the existing artificial pancreas systems with syringe pumps, an energy-efficient, valveless piezoelectric pump is designed and simulated with different types of controllers and glucose-insulin models. COMSOL Multiphysics is used for piezoelectric-fluid-structural coupled 3D finite element simulations of the pump. Then, a reduced-order model (ROM) is simulated in MATLAB/Simulink together with optimal and proportional-integral-derivative (PID) controllers and glucose–insulin models of Ackerman, Bergman, and Sorensen. Divergence angle, nozzle/diffuser diameters, lengths, chamber height, excitation voltage, and frequency are optimized with dimensional constraints to achieve a high net flow rate and low power consumption. A prototype is manufactured and experimented with different excitation frequencies. It is shown that the proposed system successfully controls the delivered insulin for all three glucose–insulin models.

Comparison of Operator Workloads Associated with the Single-unit Anyfusion® Pump and the Changeover from a Syringe Pump to an Infusion Pump

BACKGROUND

A changeover from a syringe pump to an infusion pump may transiently interrupt drug administration and result in medication errors. A newly developed infusion device (Anyfusion®) that combines the functions of an infusion pump and a syringe pump in a single unit was recently commercialized. This study compared the operator workloads associated with the Anyfusion® pump and with the conventional method using two infusion devices (a syringe pump and an infusion pump).

METHODS

This was a prospective, randomized, crossover-designed simulation study using an imitation arm with an intravascular line. We compared the two methods in terms of total execution time, total number of button clicks, and subjective difficulty using a numerical rating scale with a score from 0 (extremely easy) to 10 (extremely difficult).

RESULTS

Twenty-two nurses successfully performed both interventions according to the allocated sequence. Total execution times did not differ between the two methods (129.5 ± 23.2 seconds for the conventional method vs. 121.2 ± 24.3 seconds for the Anyfusion® method; P = 0.244), although the total number of clicks was significantly fewer using the Anyfusion® than the conventional method (median [interquartile range]: 10.0 [9.0-12.0] vs. 21.0 [20.0-25.0], respectively; P < 0.001). Participants rated the Anyfusion® method as easier than the conventional method (1.7 ± 1.2 vs. 3.6 ± 1.6; P < 0.001, respectively).

CONCLUSION

The introduction of Anyfusion® lessened the workload of practitioners required by the changeover process, which might reduce the risk of medication errors and subsequent patient harm.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0004172.

Syringe infusion pump with absolute piston displacement control

A vast majority of syringe pumps operate on stepper motors, which limits their effectiveness for precision fluid delivery using estimation algorithms. Such a system also hampers the ability to ascertain if the infusion or aspiration instruction has been correctly carried out in the event of power interruptions. To address this issue, a linear servo based actuator system is described to provide absolute indications of the plunger position. System performance in terms of linearity and reliability of plunger translation were verified using a camera tracking system with syringe capacities ranging from 3 to 50 ml and at syringe plunger speeds ranging from 1 to 6.6 mm/s when distilled water was used as the medium. In investigations involving more viscous liquids, the system revealed similarly linear characteristics with 50% glycerol-water (v/v), but cyclical stick-slip behavior with Freund's adjuvant.

A Hazard Analysis of Class I Recalls of Infusion Pumps

BACKGROUND

The adverse event report of medical devices is one of the postmarket surveillance tools used by regulators to monitor device performance, detect potential device-related safety issues, and contribute to benefit-risk assessments of these products. However, with the development of the related technologies and market, the number of adverse events has also been on the rise, which in turn results in the need to develop efficient tools that help to analyze adverse events monitoring data and to identify risk signals.

OBJECTIVE

This study aimed to establish a hazard classification framework of medical devices and to apply it over practical adverse event data on infusion pumps. Subsequently, it aimed to analyze the risks of infusion pumps and to provide a reference for the risk management of this type of device.

METHODS

The authors define a general hierarchical classification of medical device hazards. This classification is combined with the Trace Intersecting Theory to form a human-machine-environment interaction model. Such a model was applied to the dataset of 2001 to 2017 class I infusion pump recalls extracted from the Food and Drug Administration (FDA) website. This dataset does not include cases involving illegal factors.

RESULTS

The proposed model was used for conducting hazard analysis on 70 cases of class I infusion pump recalls by the FDA. According to the analytical results, an important source of product technical risk was that the infusion pumps did not infuse accurate dosage (ie, over- or underdelivery of fluid). In addition, energy hazard and product component failure were identified as the major hazard form associated with infusion pump use and as the main direct cause for adverse events in the studied cases, respectively.

CONCLUSIONS

The proposed human-machine-environment interaction model, when applied to adverse event data, can help to identify the hazard forms and direct causes of adverse events associated with medical device use.