Assessment of using fingerstick blood sample with i-STAT point-of-care device for cardiac troponin I assay

Pre-hospital evaluation of chest pain patients using the modified HEART-score: rationale and design

Background: This study assesses how ambulance paramedics using the modified HEART-score with a point-of-care cardiac troponin (cTn) compare to the emergency physicians using the modified HEART-score with a high-sensitive cTn (hs-cTn) in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS), focusing on interobserver agreement and diagnostic performance. Methods: In this prospective multicenter cohort, we compare four cTn testing strategies (serial point of care and hs-cTn cTn measurement) with and without the HEART-score. Outcomes include the HEART-score's interobserver agreement, NSTE-ACS at discharge, major adverse cardiovascular events (MACE) after 30 days, and diagnostic accuracy of the different strategies. Conclusion: The POPular HEART study aims to improve NSTE-ACS diagnostic pathways, promoting pre-hospital detection and ruling out of NSTE-ACS to minimize unnecessary hospitalizations and associated costs.Clinical Trial Registration: NCT04851418 (ClinicalTrials.gov).

Clinical performance of 0/1 h cardiac troponin algorithm for diagnosing non-ST-segment elevation myocardial infarction in an emergency setting

BACKGROUND

Non-ST-segment elevation myocardial infarction (NSTEMI) is a common form of acute myocardial infarction and rapid and accurate diagnosis is crucial for timely treatment. Current guidelines recommend using high-sensitivity cardiac troponin (hs-cTn) assays to determine circulating cTnI or cTnT levels. While the accuracy of the 0 h/1 h algorithm for diagnosing NSTEMI in different regions and patient populations remains controversial. Additionally, point-of-care testing (POCT) cTn assays have the potential to provide troponin readings to physicians within 15 min, but their accuracy in diagnosing NSTEMI in the emergency department (ED) requires further investigation.

METHODS

A single-center prospective observational cohort study was conducted at Shaanxi Provincial People's Hospital to assess the analytical and diagnostic performance of the laboratory-based Roche Modular E170 hs-cTnT using the 0 h/1 h algorithm with Radiometer AQT90-flex POCT cTnT assay in undifferentiated chest pain patients presenting to the ED. Whole-blood samples were collected and hs-cTnT and POCT cTnI were measured simultaneously at baseline and after 1 h.

RESULTS

The study results showed that the POCT cTnT assay using the 0 h/1 h algorithm had comparable diagnostic accuracy to the laboratory-based Roche Modular E170 hs-cTnT assay in diagnosing NSTEMI in patients with chest pain.

CONCLUSION

The laboratory-based Roche Modular E170 hs-cTnT using the 0 h/1 h algorithm is reliable and accurate method for diagnosing NSTEMI in undifferentiated chest pain patients presenting to the ED. POCT cTnT assay has comparable diagnostic accuracy to the hs-cTnT assay and its rapid turnaround time makes it a valuable tool in expediting the diagnostic workup of chest pain patients.

Flexible and porous microneedles of PDMS for continuous glucose monitoring

Microneedle (MN) is a key technology of the biomedical engineering field due to its capability of accessing the biological information in a minimally invasive manner. One of the huge demands for next-generation healthcare monitoring is continuous monitoring, especially of blood glucose concentration. For this, MN should be kept inserted into the human skin for a certain period of time, enduring stresses induced by daily human motion and at the same time measuring biomarkers in ISF. However, conventional MNs for biosensing are not suitable for a long term insertion due to the rigid structure and biological risks of MN breakage. In this study, a novel MN structure is proposed and investigated by combining flexible "sponge-like" porous PDMS matrix and coating by biodissolving hyaluronic acid (HA). The fabricated porous MNs coated with HA show ideal mechanical characteristics, by which the MNs are rigid enough to penetrate the skin and become flexible after insertion into the skin. It is also shown that the MN array successfully extracts ISF in vitro and in vivo not by capillary action but by repeated compressions. The results show the applicability of the flexible MNs to continuous blood glucose monitoring.

Cardiac biomarker measurement by point of care testing - Development, rationale, current state and future developments

Cardiac biomarker measurements are integral to the diagnosis and management of patients presenting with breathlessness and chest pain. Measurement of B type natriuretic peptide either directly or of the N-terminal portion of the prohormone although possible by point of care testing (POCT) has largely become a laboratory test. Measurement of the cardiac troponins cardiac troponin T (cTnT) and cardiac troponin I (cTnI) can easily and accurately be performed by POCT. The situation has been complicated by the development of high sensitivity assays for cTnT and cTnI and the subsequent development of rapid rule out algorithms allowing patient categorisation and discharge on admission and 1 to 2 h following admission. This article reviews the development of POCT for cardiac biomarkers, the evidence base comparing POCT with central laboratory testing, its strengths and limitations, and how POCT fits into the world of high sensitivity troponin assays. It also discusses what evidence there is that POCT can form part of rapid decision-making strategies and how this applies in an era of algorithms based on and is derived from measurement of high sensitivity troponin in the central laboratory.

Microfluidic chip to interface porous microneedles for ISF collection

Porous microneedles (MNs) are expected to be applied for diagnostic microfluidic devices such as blood glucose monitoring as they enable a pain-free penetration of human skin and the extraction of interstitial fluids. However, conventional microfluidic systems require additional steps to separate the liquid from a porous structure used for fluid extraction. In this study, we developed a microfluidic system with a hydrodynamically designed interface between a porous MN array and microchannels to enable a direct analysis of liquids extracted by the porous MN array. The microfluidic chip with an interface for the MN array was successfully realized by standard MEMS processes, enabling a liquid flow through the whole microfluidic structure. The porous MN array was fabricated by the salt leaching and molding method, which was integrated with the chip and demonstrated the successful extraction of liquids from an agarose gel-based skin phantom.

Monitoring drug pharmacokinetics and immunologic biomarkers in dermal interstitial fluid using a microneedle patch

Minimally invasive point-of-care diagnostic devices are of great interest for rapid detection of biomarkers in diverse settings. Although blood is the most common source of biomarkers, interstitial fluid (ISF) is an alternate body fluid that does not clot or contain red blood cells that often complicate analysis. However, ISF is difficult to collect. In this study, we assessed the utility of a microneedle patch to sample microliter volumes of ISF in a simple and minimally invasive manner. We demonstrated the use of ISF collected in this way for therapeutic drug monitoring by showing similar vancomycin pharmacokinetic profiles in ISF and serum from rats. We also measured polio-specific neutralizing antibodies and anti-polio IgG in ISF similar to serum in rats immunized with polio vaccine. These studies demonstrate the potential utility of ISF collected by microneedle patch in therapeutic drug monitoring and immunodiagnostic applications.

Functionalized microneedles for continuous glucose monitoring

Microneedles (MNs) have been established as promising medical devices as they are minimally invasive, cause less pain, and can be utilized for self-administration of drugs by patients. There has been rapid development in MNs for transdermal monitoring and diagnostic systems, following the active research on fabrication methods and applications for drug delivery. In this paper, recent investigations on bio-sensing using MNs are reviewed in terms of the applicability to continuous glucose monitoring system (CGMS), which is one of the main research focuses of medical engineering technologies. The trend of the functionalized MNs can be categorized as follows: (i) as a sensing probe, and (ii) as a biological fluid collector. MNs as in vivo sensors are mainly integrated or coated with conductive materials to have the function as electrodes. MNs as fluid collectors are given a certain geometrical design, such as a hollow and porous structure aided by a capillary action or negative pressure, to extract the interstitial fluids or blood for ex vivo analysis. For realization of CGMS with MNs, a long-term accurate measurement by the MN-based sensing probe or a fluidic connection between the MN-based fluid collector and the existing microfluidic measurement systems should be investigated.

Automated end-to-end blood testing at the point-of-care: Integration of robotic phlebotomy with downstream sample processing

Diagnostic blood testing is the most commonly performed clinical procedure in the world, and influences the majority of medical decisions made in hospital and laboratory settings. However, manual blood draw success rates are dependent on clinician skill and patient physiology, and results are generated almost exclusively in centralized labs from large-volume samples using labor-intensive analytical techniques. This paper presents a medical device that enables end-to-end blood testing by performing blood draws and providing diagnostic results in a fully automated fashion at the point-of-care. The system couples an image-guided venipuncture robot, developed to address the challenges of routine venous access, with a centrifuge-based blood analyzer to obtain quantitative measurements of hematology. We first demonstrate a white blood cell assay on the analyzer, using a blood mimicking fluid spiked with fluorescent microbeads, where the area of the packed bead layer is correlated with the bead concentration. Next we perform experiments to evaluate the pumping efficiency of the sample handling module. Finally, studies are conducted on the integrated device - from blood draw to analysis - using blood vessel phantoms to assess the accuracy and repeatability of the resulting white blood cell assay.

Mechanisms of sampling interstitial fluid from skin using a microneedle patch

Although interstitial fluid (ISF) contains biomarkers of physiological significance and medical interest, sampling of ISF for clinical applications has made limited impact due to a lack of simple, clinically useful techniques that collect more than nanoliter volumes of ISF. This study describes experimental and theoretical analysis of ISF transport from skin using microneedle (MN) patches and demonstrates collection of >1 µL of ISF within 20 min in pig cadaver skin and living human subjects using an optimized system. MN patches containing arrays of submillimeter solid, porous, or hollow needles were used to penetrate superficial skin layers and access ISF through micropores (µpores) formed upon insertion. Experimental studies in pig skin found that ISF collection depended on transport mechanism according to the rank order diffusion < capillary action < osmosis < pressure-driven convection, under the conditions studied. These findings were in agreement with independent theoretical modeling that considered transport within skin, across the interface between skin and µpores, and within µpores to the skin surface. This analysis indicated that the rate-limiting step for ISF sampling is transport through the dermis. Based on these studies and other considerations like safety and convenience for future clinical use, we designed an MN patch prototype to sample ISF using suction as the driving force. Using this approach, we collected ISF from human volunteers and identified the presence of biomarkers in the collected ISF. In this way, sampling ISF from skin using an MN patch could enable collection of ISF for use in research and medicine.

Heat stroke

Heat stroke is a life-threatening condition clinically diagnosed as a severe elevation in body temperature with central nervous system dysfunction that often includes combativeness, delirium, seizures, and coma. Classic heat stroke primarily occurs in immunocompromised individuals during annual heat waves. Exertional heat stroke is observed in young fit individuals performing strenuous physical activity in hot or temperature environments. Long-term consequences of heat stroke are thought to be due to a systemic inflammatory response syndrome. This article provides a comprehensive review of recent advances in the identification of risk factors that predispose to heat stroke, the role of endotoxin and cytokines in mediation of multi-organ damage, the incidence of hypothermia and fever during heat stroke recovery, clinical biomarkers of organ damage severity, and protective cooling strategies. Risk factors include environmental factors, medications, drug use, compromised health status, and genetic conditions. The role of endotoxin and cytokines is discussed in the framework of research conducted over 30 years ago that requires reassessment to more clearly identify the role of these factors in the systemic inflammatory response syndrome. We challenge the notion that hypothalamic damage is responsible for thermoregulatory disturbances during heat stroke recovery and highlight recent advances in our understanding of the regulated nature of these responses. The need for more sensitive clinical biomarkers of organ damage is examined. Conventional and emerging cooling methods are discussed with reference to protection against peripheral organ damage and selective brain cooling.