Failure Of Medical Devices Research Articles

Evaluating record history of medical devices using association discovery and clustering techniques

In this research, association discovery and clustering techniques were utilized for improving the efficiency of a hospital’s service and of the maintenance tasks in a clinical engineering department. The indicator in this study is service requests. The association discovery techniques revealed problems in users’ training (errors in operating procedures), intrinsic failures in medical devices, and badly scheduled maintenance policies. Clustering techniques uncovered the main causes of failures. With the evidence obtained corrective actions were taken. The service request average dropped dramatically from 6.4 to 0.4 during the analyzed period.

Enhancing antibacterial activity of surface-grafted chitosan with immobilized lysozyme on bioinspired stainless steel substrates

Bacterial infections have been widely recognized as a major cause of the failure of medical implants and devices. One promising strategy to reduce the incidence of infections is to impart the material surfaces with bactericidal function for inhibiting bacterial adhesion and biofilm formation. In this study, stainless steel (SS) surface was first activated by a biomimetic dopamine anchor to provide active amino groups, followed by covalently immobilizing chitosan (CS) with glutaraldehyde (GA) as a bifunctional linker. Hen egg white lysozyme, a natural defensive enzyme, was finally conjugated to the grafted chitosan to enhance biocidal functionality. The antibacterial assay results demonstrated substantial enhancement in bactericidal efficiency against Staphylococcus aureus (S. aureus) on the lysozyme-immobilized SS substrates under the neutral pH conditions as compared to the chitosan-grafted SS substrates. With the inherent advantages of robust anchoring ability of dopamine and specific functionality of lysozyme, the metallic substrates can be readily tailored with antibacterial property to combat biomaterial-centered infection for potential biomedical applications.

FDA Regulation of Medical Devices and Medical Device Reporting

There are three main stakeholders in medical device regulation: people in industry, regulators and practitioners. A medical device report is filed after a device-related adverse event occurs. Studies show that while most medical device reports begin with practitioner observations, people in industry file 97% of reports and practitioners file 3% of reports. The objectives of this article are to identify the major areas of focus in medical device regulation according to industry, regulators, and practitioners, and to investigate the feasibility of increased practitioner participation in medical device reporting. The author interviewed 5 industry, 5 regulators, and 6 practitioners. The stakeholders’ views were influenced by their personal distribution on the importance of outcomes such as cost, speed, safety and effectiveness. Industry, regulators and practitioners’ main perspectives were that medical device regulation is inconsistent and unpredictable, and that the US medical device industry is lagging behind Europe. Individual stakeholder goals were not aligned and caused bias resulting in a varied depiction of FDA regulation of medical devices. A practitioner-focused survey on medical device reporting was sent to 1567 practitioners in the University of Pennsylvania Health System. 340 survey responses showed that 46% of practitioners have witnessed a medical device failure, but only 19% have ever filed a medical device report. The survey results revealed that practitioners do not currently have enough experience or knowledge about medical device reporting to participate effectively and positively impact postmarket surveillance

Patient safety in vitreoretinal surgery: quality improvements following a patient safety reporting system

AimsVitreoretinal (VR) surgery is complex. Most clinical conditions that VR surgeons manage have a high risk for blindness or severe visual impairment. Reporting of patient safety incidents (PSI) in VR...

Generating knowledge for the identification of device failure causes and the prediction of the times-to-failure in u-Healthcare environments

The healthcare industry depends on a large number of medical devices to perform many of its functions, so a considerable amount of effort is spent to deal with failures occurred in medical devices. This paper proposes a method that generates knowledge used to identify the causes of medical device failures and to predict the times-to-failure (i.e., a period during which a medical device operates without failure). To generate knowledge for failure cause identification, morphemes of the failure data in the existing database are analyzed and similar failures (symptoms and causes) are grouped based on the similarity of symptoms. To generate knowledge for the prediction of the times-to-failure, the Weibull distribution parameters are estimated based on a device's previous failure dates. The experiment results show that the proposed method has 69 % accuracy in identifying the cause of failure and 83 % accuracy in predicting the times-to-failure. The proposed method enables medical device users to quickly identify the cause of failure when their devices have problems, thereby reducing the cost of failure. With the predicted time to failure, it is possible to have devices (or device parts) ready just in time for replacement. This leads to decreased inventory costs.

Superparamagnetic Iron Oxide Nanoparticles (SPION) for the Treatment of Antibiotic‐Resistant Biofilms

Bacterial infections caused by antibiotic-resistant strains are of deep concern due to an increasing prevalence, and are a major cause of morbidity in the United States of America. In particular, medical device failures, and thus human lives, are greatly impacted by infections, where the treatments required are further complicated by the tendency of pathogenic bacteria, such as Staphylococcus aureus, to produce antibiotic resistant biofilms. In this study, a panel of relevant antibiotics used clinically including penicillin, oxacillin, gentamicin, streptomycin, and vancomycin are tested, and although antibiotics are effective against free-floating planktonic S. aureus, either no change in biofilm function is observed, or, more frequently, biofilm function is enhanced. As an alternative, superparamagnetic iron oxide nanoparticles (SPION) are synthesized through a two-step process with dimercaptosuccinic acid as a chelator, followed by the conjugation of metals including iron, zinc, and silver; thus, the antibacterial properties of the metals are coupled to the superparamagnetic properties of SPION. SPION might be the ideal antibacterial treatment, with a superior ability to decrease multiple bacterial functions, target infections in a magnetic field, and had activity better than antibiotics or metal salts alone, as is required for the treatment of medical device infections for which no treatment exists today.

Regulation of medical devices used in diabetology in Europe: Time for reform?

To the Editor: A series of high-profile failures of medical devices in recent years has resulted in much debate in Europe as to the approval process and subsequent regulation of devices used in medical practice [1, 2]. Such is the concern about the perceived lack of regulation and monitoring of devices that barely a week has passed in early 2012 without reports or comments on device failures in the medical literature. These have ranged from the spontaneous rupture of Poly Implant Prosthese (PIP; La Seyne-sur-Mer, France) silicone gel breast implants [3] and the dangers of metal on metal hip implants [4, 5], to deaths caused by the likely failure of implantable cardioverter–defibrillator leads [6, 7]. Fortunately, to date and to our knowledge, such serious failures have not been reported for devices used in the management of patients with diabetes. However, faced with the rapid increase of device usage in the treatment of diabetes, the EASD earlier this year hosted a meeting of interested parties from the diabetes associations, industry, academia and the European Commission to discuss European perspectives on medical devices used in diabetes [8]. In this letter, we review the usage of devices in diabetes treatment, describe the current European regulations for device registration and monitoring, and outline the urgent need for reform of the entire process.

Rethinking medical device regulation

Rethinking medical device regulation

Dependable and secure computing in medical information systems

Medical information systems facilitate ambulatory patient care, and increase safer and more intelligent diagnostic and therapeutic capabilities through automated interoperability among distributed medical devices. In modern medical information systems, dependability is one of the most important factors for patient safety in the presence of delayed or lost system alarm and data streams due to the intermittent medical device network connection or failure. In addition, since the medical information need to be frequently audited by many human operators as well as the automated medical devices, secure access control is another pivotal factor for patient privacy and data confidentiality against inside or outside adversaries. In this study, we propose a dependable and secure access policy enforcement scheme for disruption-tolerant medical information systems. The proposed scheme exploits the external storage node operated by the device controller, which enables reliable communications between medical devices. Fine-grained data access control is also achieved, while the key escrow problem is resolved such that any curious device controller or key generation center cannot decrypt the private medical data of patients. The proposed scheme allows the device controller to partially decrypt the encrypted medical information for the authorized receivers with their corresponding attributes without leaking any confidential information to it. Thus, computational efficiency at the medical devices is also enhanced by enabling the medical devices to delegate most laborious tasks of decryption to the device controller.

Minimally invasive, longitudinal monitoring of biomaterial-associated inflammation by fluorescence imaging

Implant-associated inflammation is a major cause for the reduced performance/lifetime and failure of numerous medical devices. Therefore, the ability to non-invasively and quantitatively monitor implant-associated inflammation is critically important. Here we show that implant-associated inflammation can be imaged via fluorescence imaging using near-infrared hydrocyanine dyes delivered either locally or intravenously in living mice. This imaging strategy allowed quantitative longitudinal monitoring of inflammation by detecting reactive oxygen species (ROS) released by inflammatory cells in response to implanted poly(ethylene terephthalate) (PET) disks or injected poly (lactic-co-glycolic acid) (PLGA) microparticles, and exhibited a strong correlation to conventional analysis of inflammation. Furthermore, modulation of inflammatory responses via controlled release of the anti-inflammatory agent dexamethasone was detected using this sensitive imaging approach. Thus, hydrocyanine-based fluorescence imaging of ROS could serve as a surrogate measure for monitoring implant-associated inflammation as well as evaluating the efficacy of therapeutic approaches to modulate host responses to implanted medical devices.

Device Complications: What Does the Surgeon Do?

Program Description: Medical device failures are commonly associated with surgical complications. In late 1997, the US FDA (Food and Drug Administration) reported that it receives approximately 100,000 medical device reports a year, and the agency considers this number just the tip of the medical device problem iceberg. Any surgeon is very likely to experience this complication in his or her operative career. The Pediatric Otolaryngology and the Medical Devices and Drugs Committee decided to organize a miniseminar to provide guidelines to surgeons experiencing this complication and for surgeons wishing to be informed to device failures. The symposium will be divided into two major parts. In the first part, clinical cases associated with medical device failures will be presented. The impact of one of these cases based on a national survey of pediatric otolaryngologists will be highlighted. The second part will then include the medicolegal ramifications, disclosure to patients and families, and resources available for the surgeon to report and receive updates on device failures. Educational Objectives: 1) Learn the role of the surgeon in disclosing device complications to patients and national reporting agencies. 2) Learn the medicolegal ramifications of a device failure to the surgeon. 3) Learn how an otolaryngologist can keep him or herself informed of device recalls or complications.

Bacterial adhesion reduction on a biocompatible Si + ion implanted austenitic stainless steel

The colonization of an implant surface by bacteria is an extremely important medical problem, which often leads to the failure of medical devices. Modern surface modification techniques, such as ion implantation, can confer to the surfaces very different properties from those of the bulk underlying material. In this work, austenitic stainless steel 316 LVM has been superficially modified by Si + ion implantation. The effect of surface modification on the biocompatibility and bacterial adhesion to 316 LVM stainless steel has been investigated. To this aim, human mesenchymal stem cells (hMSCs), as precursor of osteoblastic cells, and bacterial strains relevant in infections related to orthopedic implants, i.e., Staphylococcus aureus and Staphylococcus epidermidis, have been assayed. For the understanding of changes in the biological response associated to ion implantation, variations in the chemical surface composition, topography, surface Gibbs energy, isoelectric point and in vitro corrosion behavior have been evaluated. hMSCs adhesion, viability and differentiation to the osteoblastic lineage were unaffected by Si + ion implantation. On the other hand, Si + ion implantation diminished the number of attached bacteria in static conditions and led to smaller adhesion rates and retention strength. The ability of implanted surfaces to reduce the bacterial adhesion was higher for Staphylococcus epidermidis than for Staphylococcus aureus. This study proposes Si + ion implantation as an effective way of reducing bacterial adhesion on 316 LVM stainless steel surfaces without compromising its good biocompatibility.

Guidelines From 80001 : Maintaining a Medical IT Network

<i>Guidelines From 80001</i> : Maintaining a Medical IT Network

Prevention of Implantable Medical Device Failure (IMD) Associated with Biofilm Infection

Prevention of Implantable Medical Device Failure (IMD) Associated with Biofilm Infection

Evaluating surface bound rTFPI through an in vitro model of vessel wall injury

Introduction Injury to the surrounding vessel wall is one of the major reasons for failure of implantable medical devices. The surgical procedure itself or the altered flow conditions after implantation can cause damage to the vessel wall. This damage exposes tissue factor (TF), the initiator of the extrinsic pathway of coagulation. One approach to combat thrombosis is to use an anticoagulant on the surface of the device. The primary aim of this study is to develop a simplified physiologically relevant in vitro model of vessel wall injury to study the mechanisms by which immobilized recombinant tissue factor pathway inhibitor (rTFPI) effectively inhibits TF initiated thrombosis. Materials and methods A two well chamber slide was used for the study. Fibroblasts were cultured on the upstream portion of the slide. Fibroblast cells stimulated with TNF-α acted as a source of surface TF. The downstream portion of the slide was coated with rTFPI. A mixture of FX, FVIIa and calcium was perfused over the slides to generate FXa. Effluent collected at the outlet was used to analyze the inhibition of this surface generated FXa by the rTFPI present downstream. Results and conclusions Different shear rates and rTFPI densities were used to study this effect. In most cases rTFPI inhibited FXa generated upstream as a function of the wall shear rate and rTFPI dosage (surface density). This study shows the effectiveness of the surface bound inhibitor when FXa is generated from an upstream injury site and the bulk of FXa is near the wall.

Ultrasonic Cleaning-Induced Failures in Medical Devices

Ultrasonic cleaning is often used as part of the manufacturing process of small medical devices such as guide wires and vascular implants. Ultrasonic cleaning at frequencies close to the natural frequency of the device can result in resonance, resulting in significant mechanical damage and possibly premature failure. This paper provides case studies of ultrasonic cleaning-induced fatigue and corresponding failures in small medical devices. Preventative measures, including analytical tools such as finite element analysis (FEA), to ensure that ultrasonic cleaning frequencies do not result in resonance and stresses sufficient to cause fatigue damage are also discussed.

Assess Your Patient Safety Readiness

What comes first, the chicken or the egg? biomedical/clinical engineering (BME/ CE) departments and professionals that are interested in becoming more involved in patient safety initiatives may find this self-assessment tool to be a good reference to use to assess and enhance their programs. The tool is meant to give the reader a road map to ensure that he or she has all the necessary resources, policies, procedures, and training (e.g. in conducting medical device investigations, Failure Mode and Effect Analysis (FMEA) and Root Cause Analysis) before they offer to become more involved in the patient-safety movement at their facilities. The measurement of involvement may be approached from two perspectives: I. Prospective Risk Assessment (prevention is better than cure) II. Retrospective Risk Assessment (lessons to be learned) Please use the criteria below to assess your department’s level of involvement.

Controlling the release of peptide antimicrobial agents from surfaces

Medical conditions are often exacerbated by the onset of infection caused by hospital dwelling bacteria such as Staphylococcus aureus. Antibiotics taken orally or intravenously can require large and frequent doses, further contributing to the sharp rise in resistant bacteria observed over the past several decades. These existing antibiotics are also often ineffective in preventing biofilm formation, a common cause of medical device failure. Local delivery of new therapeutic agents that do not allow bacterial resistance to occur, such as antimicrobial peptides, could alleviate many of the problems associated with current antibacterial treatments. By taking advantage of the versatility of layer-by-layer assembly of polymer thin films, ponericin G1, an antimicrobial peptide known to be highly active against S. aureus, was incorporated into a hydrolytically degradable polyelectrolyte multilayer film. Several film architectures were examined to obtain various drug loadings that ranged from 20 to 150 μg/cm 2. Release was observed over approximately ten days, with varying release profiles, including burst as well as linear release. Results indicated that film-released peptide did not suffer any loss in activity against S. aureus and was able to inhibit bacteria attachment, a necessary step in preventing biofilm formation. Additionally, all films were found to be biocompatible with the relevant wound healing cells, NIH 3T3 fibroblasts and human umbilical vein endothelial cells. These films provide the level of control over drug loading and release kinetics required in medically relevant applications including coatings for implant materials and bandages, while eliminating susceptibility to bacterial resistance.

Persistence of antimicrobial activity through sustained release of triclosan from pegylated silicone elastomers

Microbial adhesion to silicone elastomer biomaterials is a major problem often resulting in infection and medical device failure. Several strategies have been employed to modulate eukaryotic cell adhesion and to hamper bacterial adherence to polymeric biomaterials. Chemical modification of the surface by grafting of polyethylene glycol (PEG) chains or the incorporation of non-antibiotic antimicrobial agents such as triclosan into the biomaterial matrix may reduce bacterial adhesion. Here, such strategies are simultaneously applied to the preparation of both condensation-cure and addition-cure silicone elastomer systems, seeking a sustained release antimicrobial device biomaterial. The influence of triclosan incorporation and degree of pegylation on antimicrobial release, surface microbial adherence and persistence ( Escherichia coli and Staphylococcus epidermidis) were evaluated in vitro. Non-pegylated silicone elastomers provided an increased percentage release of triclosan extending over a relatively short duration (99% release by day 64) compared with their pegylated (4% w/w) counterparts (65% and 72% release by day 64, for condensation and addition-cure systems respectively). Viable E. coli adherence to a non-pegylated silicone elastomer containing 1% w/w triclosan was reduced by over 99% after 24 h compared to the non-pegylated silicone elastomer containing no triclosan. No viable S. epidermidis adhered to any of the triclosan-loaded (>0.1% w/w) formulations other than the control. Persistence of the antimicrobial activity of the triclosan-loaded pegylated silicone elastomers continued for at least 70 days compared to the triclosan-loaded non-pegylated elastomers (at least 49 days). Understanding how PEG affects the release of triclosan from silicone elastomers may prove useful in the development of a biomaterial providing prolonged, effective antimicrobial activity.

Detection and identification of specific bacteria in wound biofilms using peptide nucleic acid fluorescent in situ hybridization (PNA FISH)

Biofilms provide a reservoir of potentially infectious micro-organisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic inflammatory conditions is increasingly being recognized. Particular research interest exists in the association of biofilms with wound infection and non-healing, i.e. chronic wounds. In this study, fluorescent in situ hybridization (FISH) was used in combination with confocal laser scanning microscopy (CLSM) to detect and characterize the spatial distribution of biofilm-forming bacteria which predominate within human chronic skin wounds (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Micrococcus sp.). In vitro biofilms were prepared using a constant-depth film fermenter and a reconstituted human epidermis model. In vivo biofilms were also studied using biopsy samples from non-infected chronic venous leg ulcers. The specificity of peptide nucleic acid (PNA) probes for the target organisms was confirmed using mixed preparations of planktonic bacteria and multiplex PNA probing. Identification and location of individual bacterial species within multi-species biofilms demonstrated that P. aeruginosa was predominant. CLSM revealed clustering of individual species within mixed-species biofilms. FISH analysis of archive chronic wound biopsy sections showed bacterial presence and allowed bacterial load to be determined. The application of this standardized procedure makes available an assay for identification of single- or multi-species bacterial populations in tissue biopsies. The technique provides a reliable tool to study bacterial biofilm formation and offers an approach to assess targeted biofilm disruption strategies in vivo.