383 research outputs found
Optimal positive end-expiratory pressure in mechanically ventilated patients: a clinical study
The optimal level of positive end-expiratory pressure (PEEP) is still widely debated in treating acute respiratory distress syndrome (ARDS) patients. Current methods of selecting PEEP only provide a range of values and do not provide unique patient-specific solutions. Model-based methods offer a novel way of using non-invasive pressure-volume (PV) measurements to estimate patient recruitability. This paper examines the clinical viability of such models in pilot clinical trials to assist therapy, optimise patient-specific PEEP, assess the disease state and response over time
Model-based cardiovascular monitoring of acute pulmonary embolism in porcine trials
Introduction:
Diagnosis and treatment of cardiac and circulatory dysfunction can be error-prone and relies heavily on clinical
intuition and experience. Model-based approaches utilising measurements available in the Intensive care unit
(ICU) can provide a clearer physiological picture of a patient’s cardiovascular status to assist medical staff with
diagnosis and therapy decisions. This research tests a subject-specific cardiovascular system (CVS) modelling
technique on measurements from a porcine model of acute pulmonary embolism (APE).
Methods:
Measurements were recorded in 5 pig trials, where autologous blood clots were inserted every two hours into
the jugular vein to simulate pulmonary emboli. Of these measurements only a minimal set of clinically available or
inferable data were used in the identification process (aortic and pulmonary artery pressure, stroke volume, heart
rate, global end diastolic volume, and mitral and tricuspid valve closure times).
The CVS model was fitted to 46 sets of data taken at 30 minute intervals (t=0, 30, 60, …, 270) during the induction
of APE to identify physiological model parameters and their change over time in APE. Model parameters and
outputs were compared to experimentally derived metrics and measurements not used in the identification
method to validate the accuracy of the model and assess its diagnostic capability.
Results:
Modelled mean ventricular volumes and maximum ventricular pressures matched measured values with median
absolute errors of 4.3% and 4.4%, which are less than experimental measurement noise (~10%). An increase in
pulmonary vascular resistance, the main hemodynamic consequence of APE, was identified in all the pigs and
related well to experimental values (R=0.68). Detrimental changes in reflex responses, such as decreased right
ventricular contractility, were noticed in two pigs that died during the trial, diagnosing the loss of autonomous
control. Increases in the ratio of the modelled right to left ventricular end diastolic volumes, signifying the
leftward shift of the intra-ventricular septum seen in APE, compared well to the clinically measured index
(R=0.88).
Conclusions:
Subject-specific CVS models can accurately and continuously diagnose and track acute disease dependent
cardiovascular changes resulting from APE using readily available measurements. Human trials are underway to
clinically validate these animal trial results
Computer-based monitoring of global cardiovascular dynamics during acute pulmonary embolism and septic shock in swine
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Pulmonary embolism diagnostics from the driver function
Ventricular driver functions are not readily measured in the ICU, but can clearly indicate the development of pulmonary embolism (PE) otherwise difficult to diagnose. Recent work has developed accurate methods of
measuring these driver functions from readily available ICU measurements. This research tests those methods by assessing the ability of these driver functions to diagnose the evolution of PE
Model-based diagnosis of acute pulmonary embolism and septic shock in porcine trials
peer reviewe
Model-based cardiovascular monitoring of large pore hemofiltration during endotoxic shock in pigs
peer reviewe
Differential Dynamics of Transposable Elements during Long-Term Diploidization of Nicotiana Section Repandae (Solanaceae) Allopolyploid Genomes
PubMed ID: 23185607This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Mindfulness-based interventions for young offenders: a scoping review
Youth offending is a problem worldwide. Young people in the criminal justice system have frequently experienced adverse childhood circumstances, mental health problems, difficulties regulating emotions and poor quality of life. Mindfulness-based interventions can help people manage problems resulting from these experiences, but their usefulness for youth offending populations is not clear. This review evaluated existing evidence for mindfulness-based interventions among such populations. To be included, each study used an intervention with at least one of the three core components of mindfulness-based stress reduction (breath awareness, body awareness, mindful movement) that was delivered to young people in prison or community rehabilitation programs. No restrictions were placed on methods used. Thirteen studies were included: three randomized controlled trials, one controlled trial, three pre-post study designs, three mixed-methods approaches and three qualitative studies. Pooled numbers (n = 842) comprised 99% males aged between 14 and 23. Interventions varied so it was not possible to identify an optimal approach in terms of content, dose or intensity. Studies found some improvement in various measures of mental health, self-regulation, problematic behaviour, substance use, quality of life and criminal propensity. In those studies measuring mindfulness, changes did not reach statistical significance. Qualitative studies reported participants feeling less stressed, better able to concentrate, manage emotions and behaviour, improved social skills and that the interventions were acceptable. Generally low study quality limits the generalizability of these findings. Greater clarity on intervention components and robust mixed-methods evaluation would improve clarity of reporting and better guide future youth offending prevention programs
Physiological modeling, tight glycemic control, and the ICU clinician: what are models and how can they affect practice?
Critically ill patients are highly variable in their response to care and treatment. This variability and the search for improved outcomes have led to a significant increase in the use of protocolized care to reduce variability in care. However, protocolized care does not address the variability of outcome due to inter- and intra-patient variability, both in physiological state, and the response to disease and treatment. This lack of patient-specificity defines the opportunity for patient-specific approaches to diagnosis, care, and patient management, which are complementary to, and fit within, protocolized approaches
Time-calibrated phylogenetic trees establish a lag between polyploidisation and diversification in Nicotiana (Solanaceae)
We investigate the timing of diversification in allopolyploids of Nicotiana (Solanaceae) utilising sequence data of maternal and paternal origin to look for evidence of a lag phase during which diploidisation took place. Bayesian relaxed clock phylogenetic methods show recent allopolyploids are a result of several unique polyploidisation events, and older allopolyploid sections have undergone subsequent speciation at the polyploid level (i.e. a number of these polyploid species share a singular origin). The independently formed recent polyploid species in the genus all have mean age estimates below 1 million years ago (Ma). Nicotiana section Polydicliae (two species) evolved 1.5 Ma, N. section Repandae (four species) formed 4 Ma, and N. section Suaveolentes (*35 species) is about 6 million years old. A general trend of higher speciation rates in older polyploids is evident, but diversification dramatically increases at approximately 6 Ma (in section Suaveolentes). Nicotiana sect. Suaveolentes has spectacularly radiated to form 35 species in Australia and some Pacific islands following a lag phase of almost 6 million years. Species have filled new ecological niches and undergone extensive diploidisation (e.g. chromosome fusions bringing the ancestral allotetraploid number, n = 24, down to n = 15 and ribosomal loci numbers back to diploid condition). Considering the progenitors of Suaveolentes inhabit South America, this represents the colonisation of Australia by polyploids that have subsequently undergone a recent radiation into new environments. To our knowledge, this study is the first report of a substantial lag phase being investigated below the family level
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