7 research outputs found
Systematic framework for performance evaluation of exoskeleton actuators
AbstractWearable devices, such as exoskeletons, are becoming increasingly common and are being used mainly for improving motility and daily life autonomy, rehabilitation purposes, and as industrial aids. There are many variables that must be optimized to create an efficient, smoothly operating device. The selection of a suitable actuator is one of these variables, and the actuators are usually sized after studying the kinematic and dynamic characteristics of the target task, combining information from motion tracking, inverse dynamics, and force plates. While this may be a good method for approximate sizing of actuators, a more detailed approach is necessary to fully understand actuator performance, control algorithms or sensing strategies, and their impact on weight, dynamic performance, energy consumption, complexity, and cost. This work describes a learning-based evaluation method to provide this more detailed analysis of an actuation system for ourXoTrunkexoskeleton. The study includes: (a) a real-world experimental setup to gather kinematics and dynamics data; (b) simulation of the actuation system focusing on motor performance and control strategy; (c) experimental validation of the simulation; and (d) testing in real scenarios. This study creates a systematic framework to analyze actuator performance and control algorithms to improve operation in the real scenario by replicating the kinematics and dynamics of the human–robot interaction. Implementation of this approach shows substantial improvement in the task-related performance when applied on a back-support exoskeleton during a walking task
The use of thromboelastography (TEG) and rotational thromboelastometry (ROTEM) in neonates: a systematic review
“Developmental hemostasis” refers to the dynamic process of gradual
hemostatic maturation. Conventional coagulation tests seem to fail to
accurately depict the in vivo hemostasis, while viscoelastic tests,
thromboelastography (TEG), and rotational thromboelastometry (ROTEM)
appear very promising as they provide insight more rapidly and
accurately into the hemostatic potential. We systematically reviewed the
literature in PubMed to examine the use of TEG and ROTEM in neonates.
Our search yielded 34 studies, of which 18 concerned healthy neonates
and 16 sick neonates. These viscoelastic tests have shown accelerated
initiation of coagulation, increased clot strength, and increased
fibrinolysis in healthy neonates compared to children and adults. Cord
blood leads to a hypercoagulable state as compared to whole blood when
testing is performed with TEG. Pre-term neonates have a more
hypocoagulable profile, but balanced hemostasis, related to term
neonates, that evolves to a more procoagulant phenotype over the first
month of life. Critically ill neonates exhibit a more hypocoagulable
profile as compared to healthy neonates. TEG and ROTEM have shown
predictive value for bleeding events in critically ill neonates and
neonates undergoing cardiopulmonary bypass or therapeutic hypothermia.
Conclusion: TEG and ROTEM need to become part of the standard
coagulation assessment in clinical settings in which hemostatic
abnormalities are involved, as they seem to provide more rapid and
accurate information regarding the hemostatic profile of the neonates.
Their predictive value for bleeding events in critically ill neonates
could lead to a more targeted therapy optimizing utilization of blood
products
Comparative Performance of Four Established Neonatal Disease Scoring Systems in Predicting In-Hospital Mortality and the Potential Role of Thromboelastometry
Background: To compare the prognostic accuracy of the most commonly used indexes of mortality over time and evaluate the potential of adding thromboelastometry (ROTEM) results to these well-established clinical scores. Methods: The study population consisted of 473 consecutive term and preterm critically-ill neonates. On the first day of critical illness, modified Neonatal Multiple Organ Dysfunction (NEOMOD) scoring system, Score for Neonatal Acute Physiology (SNAP II), Perinatal extension of SNAP (SNAPPE), and SNAPPE II, were calculated and ROTEM standard extrinsically activated (EXTEM) assay was performed simultaneously. Time-to-event methodology for competing-risks was used to assess the performance of the aforementioned indexes in predicting in-hospital mortality over time. Time-dependent receiver operator characteristics curves for censored observation were compared across indexes. The addition of EXTEM parameters to each index was tested in terms of discrimination capacity. Results: The modified NEOMOD score performed similarly to SNAPPE. Both scores performed significantly better than SNAP II and SNAPPE II. Amplitude recorded at 10 min (A10) was the EXTEM parameter most strongly associated with mortality (A10 < 37 mm vs. ≥37 mm; sHR = 5.52; p < 0.001). Adding A10 to each index apparently increased the prognostic accuracy in the case of SNAP II and SNAPPE II. However, these increases did not reach statistical significance. Conclusion: Although the four existing indexes considered showed good to excellent prognostic capacity, modified NEOMOD and SNAPPE scores performed significantly better. Though larger studies are needed, adding A10 to well-established neonatal severity scores not including biomarkers of coagulopathy might improve their prediction of in-hospital mortality
Comparative Performance of Four Established Neonatal Disease Scoring Systems in Predicting In-Hospital Mortality and the Potential Role of Thromboelastometry
Background: To compare the prognostic accuracy of the most commonly used
indexes of mortality over time and evaluate the potential of adding
thromboelastometry (ROTEM) results to these well-established clinical
scores. Methods: The study population consisted of 473 consecutive term
and preterm critically-ill neonates. On the first day of critical
illness, modified Neonatal Multiple Organ Dysfunction (NEOMOD) scoring
system, Score for Neonatal Acute Physiology (SNAP II), Perinatal
extension of SNAP (SNAPPE), and SNAPPE II, were calculated and ROTEM
standard extrinsically activated (EXTEM) assay was performed
simultaneously. Time-to-event methodology for competing-risks was used
to assess the performance of the aforementioned indexes in predicting
in-hospital mortality over time. Time-dependent receiver operator
characteristics curves for censored observation were compared across
indexes. The addition of EXTEM parameters to each index was tested in
terms of discrimination capacity. Results: The modified NEOMOD score
performed similarly to SNAPPE. Both scores performed significantly
better than SNAP II and SNAPPE II. Amplitude recorded at 10 min (A10)
was the EXTEM parameter most strongly associated with mortality (A10 <
37 mm vs. & GE;37 mm; sHR = 5.52; p < 0.001). Adding A10 to each index
apparently increased the prognostic accuracy in the case of SNAP II and
SNAPPE II. However, these increases did not reach statistical
significance. Conclusion: Although the four existing indexes considered
showed good to excellent prognostic capacity, modified NEOMOD and SNAPPE
scores performed significantly better. Though larger studies are needed,
adding A10 to well-established neonatal severity scores not including
biomarkers of coagulopathy might improve their prediction of in-hospital
mortality
Table1_Development and validation of a sepsis diagnostic scoring model for neonates with suspected sepsis.docx
BackgroundWe aimed to develop and validate a diagnostic model for sepsis among neonates evaluated for suspected sepsis, by incorporating thromboelastometry parameters, maternal/neonatal risk factors, clinical signs/symptoms and laboratory results.MethodsThis retrospective cohort study included 291 neonates with presumed sepsis, hospitalized in a NICU, from 07/2014 to 07/2021. Laboratory tests were obtained on disease onset and prior to initiating antibiotic therapy. Τhromboelastometry extrinsically activated (EXTEM) assay was performed simultaneously and Tοllner and nSOFA scores were calculated. Sepsis diagnosis was the outcome variable. A 10-fold cross-validation least absolute shrinkage and selection operator logit regression procedure was applied to derive the final multivariable score. Clinical utility was evaluated by decision curve analysis.ResultsGestational age, CRP, considerable skin discoloration, liver enlargement, neutrophil left shift, and EXTEM A10, were identified as the strongest predictors and included in the Neonatal Sepsis Diagnostic (NeoSeD) model. NeoSeD score demonstrated excellent discrimination capacity for sepsis and septic shock with an AUC: 0.918 (95% CI, 0.884–0.952) and 0.974 (95% CI, 0.958–0.989) respectively, which was significantly higher compared to Töllner and nSOFA scores.ConclusionsThe NeoSeD score is simple, accurate, practical, and may contribute to a timely diagnosis of sepsis in neonates with suspected sepsis. External validation in multinational cohorts is necessary before clinical application.</p
DataSheet1_Development and validation of a sepsis diagnostic scoring model for neonates with suspected sepsis.docx
BackgroundWe aimed to develop and validate a diagnostic model for sepsis among neonates evaluated for suspected sepsis, by incorporating thromboelastometry parameters, maternal/neonatal risk factors, clinical signs/symptoms and laboratory results.MethodsThis retrospective cohort study included 291 neonates with presumed sepsis, hospitalized in a NICU, from 07/2014 to 07/2021. Laboratory tests were obtained on disease onset and prior to initiating antibiotic therapy. Τhromboelastometry extrinsically activated (EXTEM) assay was performed simultaneously and Tοllner and nSOFA scores were calculated. Sepsis diagnosis was the outcome variable. A 10-fold cross-validation least absolute shrinkage and selection operator logit regression procedure was applied to derive the final multivariable score. Clinical utility was evaluated by decision curve analysis.ResultsGestational age, CRP, considerable skin discoloration, liver enlargement, neutrophil left shift, and EXTEM A10, were identified as the strongest predictors and included in the Neonatal Sepsis Diagnostic (NeoSeD) model. NeoSeD score demonstrated excellent discrimination capacity for sepsis and septic shock with an AUC: 0.918 (95% CI, 0.884–0.952) and 0.974 (95% CI, 0.958–0.989) respectively, which was significantly higher compared to Töllner and nSOFA scores.ConclusionsThe NeoSeD score is simple, accurate, practical, and may contribute to a timely diagnosis of sepsis in neonates with suspected sepsis. External validation in multinational cohorts is necessary before clinical application.</p