ABSTRACT
With the emergence of multi- and extensive-drug (MDR/XDR) resistant Mycobacterium tuberculosis (M. tb), tuberculosis (TB) persists as one of the world's leading causes of death. Recently, isothermal DNA amplification methods received much attention due to their ease of translation onto portable point-of-care (POC) devices for TB diagnosis. In this study, we aimed to devise a simple yet robust detection method for M. tb. Amongst the numerous up-and-coming isothermal techniques, Recombinase Polymerase Amplification (RPA) was chosen for a real-time detection of TB with or without MDR. In our platform, real-time RPA (RT-RPA) was integrated on a lab-on-a-disc (LOAD) with on-board power to maintain temperature for DNA amplification. Sputa collected from healthy volunteers were spiked with respective target M. tb samples for testing. A limit of detection of 102â¯colony-forming unit per millilitre in 15â¯min was achieved, making early detection and differentiation of M. tb strains highly feasible in extreme POC settings. Our RT-RPA LOAD platform has also been successfully applied in the differentiation of MDR-TB from H37Ra, an attenuated TB strain. In summary, a quantitative RT-RPA on LOAD assay with a high level of sensitivity was developed as a foundation for further developments in medical bedside and POC diagnostics.
Subject(s)
Automation , Lab-On-A-Chip Devices , Mycobacterium tuberculosis/genetics , Nucleic Acid Amplification Techniques , Polymerase Chain Reaction , Tuberculosis, Multidrug-Resistant/genetics , Healthy Volunteers , Humans , Point-of-Care Testing , Time FactorsABSTRACT
Perioperative stroke is a devastating complication that carries high mortality and functional disability. Unfortunately, residual anaesthesia and analgesia may obscure important warning signs and may lead to a delay in the assessment and treatment of major stroke after surgery. The purpose of this review is to examine the utility of existing stroke scales, for the recognition of perioperative stroke in the general surgical population. A total of 21 stroke scales have been described in the literature. Diagnostic performance was reported in 17 scales. The majority of the stroke scales were designed to evaluate current neurological deficits after an established stroke event. Recent abbreviated stroke test, such as the Face, Arm, Speech Test (FAST), were developed to facilitate stroke identification in the emergency department. Only two stroke scales have been applied in the perioperative setting after cardiac, carotid and neurological surgeries. The modified National Institutes of Health Stroke Scale appears to be useful in detecting new subtle neurological deficits in critical care, or high dependency units after surgery. However, in the general postsurgical wards, given the concern about the workload required, abbreviated stroke tests may be more appropriate for routine regular stroke surveillance. It is hoped that these tests will provide rapid assessment of global neurological function to facilitate timely diagnosis and treatment of perioperative stroke.
Subject(s)
Intraoperative Complications/diagnosis , Postoperative Complications/diagnosis , Stroke/diagnosis , Surgical Procedures, Operative , Humans , Perioperative Period , Risk FactorsABSTRACT
Whereas high-flow nasal cannula use is gaining prevalence, its high gas flow raises concerns about aerosolization of infectious particles and spread of infection. This randomized controlled crossover non-inferiority trial (N = 20) evaluated the degree of environmental contamination by viable bacteria associated with the use of high-flow nasal cannula compared with conventional oxygen mask for critically ill patients with Gram-negative pneumonia. The results show that high-flow nasal cannula use was not associated with increased air or contact surface contamination by either Gram-negative bacteria or total bacteria, suggesting that additional infection control measures are not required.
Subject(s)
Cannula/adverse effects , Critical Illness , Environmental Pollution , Hyperbaric Oxygenation/adverse effects , Hyperbaric Oxygenation/methods , Masks/adverse effects , Pneumonia, Bacterial/therapy , Adult , Aged , Aged, 80 and over , Cross-Over Studies , Female , Gram-Negative Bacteria/isolation & purification , Humans , Male , Middle Aged , PrevalenceABSTRACT
Sepsis by bacterial infection causes high mortality in patients in intensive care unit (ICU). Rapid identification of bacterial infection is essential to ensure early appropriate administration of antibiotics to save lives of patients, yet the present benchtop molecular diagnosis is time-consuming and labor-intensive, which limits the treatment efficiency especially when the number of samples to be tested is extensive. Therefore, we hereby report a microfluidic platform lab-on-a-disc (LOAD) to provide a sample-to-answer solution. Our LOAD customized design of microfluidic channels allows automation to mimic sequential analytical steps in benchtop environment. It relies on a simple but controllable centrifugation force for the actuation of samples and reagents. Our LOAD system performs three major functions, namely DNA extraction, isothermal DNA amplification and real-time signal detection, in a predefined sequence. The disc is self-contained for conducting sample heating with chemical lysis buffer and silica microbeads are employed for DNA extraction from clinical specimens. Molecular diagnosis of specific target bacteria DNA sequences is then performed using a real-time loop-mediated isothermal amplification (RT-LAMP) with SYTO-9 as the signal reporter. Our LOAD system capable of bacterial identification of Mycobacterium tuberculosis (TB) and Acinetobacter baumanii (Ab) with the detection limits 103cfu/mL TB in sputum and 102cfu/mL Ab in blood within 2h after sample loading. The reported LOAD based on an integrated approach should address the growing needs for rapid point-of-care medical diagnosis in ICU.
Subject(s)
Acinetobacter baumannii/isolation & purification , Biosensing Techniques , DNA, Bacterial/isolation & purification , Mycobacterium tuberculosis/isolation & purification , Sepsis/microbiology , Acinetobacter baumannii/pathogenicity , DNA, Bacterial/chemistry , Humans , Microfluidic Analytical Techniques , Mycobacterium tuberculosis/pathogenicity , Organic Chemicals/chemistry , Sepsis/diagnosisABSTRACT
PURPOSE: This study aims to compare the effectiveness of weaning with adaptive support ventilation (ASV) incorporating progressively reduced or constant target minute ventilation in the protocol in postoperative care after cardiac surgery. MATERIAL AND METHODS: A randomized controlled unblinded study of 52 patients after elective coronary artery bypass surgery was carried out to determine whether a protocol incorporating a decremental target minute ventilation (DTMV) results in more rapid weaning of patients ventilated in ASV mode compared to a protocol incorporating a constant target minute ventilation. RESULTS: Median duration of mechanical ventilation (145 vs 309 minutes; P = .001) and intubation (225 vs 423 minutes; P = .005) were significantly shorter in the DTMV group. There was no difference in adverse effects (42% vs 46%) or mortality (0% vs 0%) between the 2 groups. CONCLUSIONS: Use of a DTMV protocol for postoperative ventilation of cardiac surgical patients in ASV mode results in a shorter duration of ventilation and intubation without evidence of increased risk of adverse effects.