Overlap Welded Joint Strength of 2.0 Gpa-Strength Steel Sheets Using Single-Mode Laser Wobbling

During laser overlap welding of high strength steels, a wide interface-bead width is a prerequisite for ensuring joint strength. However, a wide weld bead is accompanied by thermal effects such as thermal deformation and softening of the heat-affected zone owing to the high heat input during welding. Hot-press-forming steel with a strength of 2.0 GPa is the highest strength steel sheet in the automotive industry. When laser-welded, the minimum hardness in the heat-affected zone is less than 2/3 of the base metal hardness. In this study, single-mode laser and beam wobbling was employed to obtain a proper bead width while minimizing the heat input in the lap welding of steel sheets with a strength of 2.0 GPa. Two strategies—high frequency wobbling/high travel speed and low frequency wobbling/low travel speed—were evaluated with a laser power fixed at 1 kW. In the high frequency wobbling/high travel speed condition, the load-carrying at the overlap joint increased as the travel speed and wobbling frequency decreased. However, even in the case with the maximum fracture load, the fracture location in the tensile–shear test was the weld metal. The low frequency wobbling/low travel speed strategy was more effective in ensuring joint strength, and the fracture location in the tensile–shear test moved to the heat-affected zone. An equivalent tensile strength of 1 GPa or more was achieved by selecting appropriate parameters. Under optimal conditions, multiple weld penetrations and sufficient interface beads were confirmed on the cross section

Intracranial Pressure Patterns and Neurological Outcomes in Out-of-Hospital Cardiac Arrest Survivors after Targeted Temperature Management: A Retrospective Observational Study

We aimed to investigate intracranial pressure (ICP) changes over time and the neurologic prognosis for out-of-hospital cardiac arrest (OHCA) survivors who received targeted temperature management (TTM). ICP was measured immediately after return of spontaneous circulation (ROSC) (day 1), then at 24 h (day 2), 48 h (day 3), and 72 h (day 4), through connecting a lumbar drain catheter to a manometer or a LiquoGuard machine. Neurological outcomes were determined at 3 months after ROSC, and a poor neurological outcome was defined as Cerebral Performance Category 3–5. Of the 91 patients in this study (males, n = 67, 74%), 51 (56%) had poor neurological outcomes. ICP was significantly higher in the poor outcome group at each time point except day 4. ICP elevation was highest between days 2 and 3 in the good outcome group, and between days 1 and 2 in the poor outcome group. However, there was no difference in total ICP elevation between the poor and good outcome groups (3.0 vs. 3.1; p = 0.476). All OHCA survivors who had received TTM had elevated ICP, regardless of neurologic prognosis. However, the changing pattern of ICP levels differed depending on the neurological outcome

Association of ultra-early diffusion-weighted magnetic resonance imaging with neurological outcomes after out-of-hospital cardiac arrest

Abstract Background This study aimed to investigate the association between ultra-early (within 6 h after return of spontaneous circulation [ROSC]) brain diffusion-weighted magnetic resonance imaging (DW-MRI) and neurological outcomes in comatose survivors after out-of-hospital cardiac arrest. Methods We conducted a registry-based observational study from May 2018 to February 2022 at a Chungnam national university hospital in Daejeon, Korea. Presence of high-signal intensity (HSI) (PHSI) was defined as a HSI on DW-MRI with corresponding hypoattenuation on the apparent diffusion coefficient map irrespective of volume after hypoxic ischemic brain injury; absence of HSI was defined as AHSI. The primary outcome was the dichotomized cerebral performance category (CPC) at 6 months, defined as good (CPC 1–2) or poor (CPC 3–5). Results Of the 110 patients (30 women [27.3%]; median (interquartile range [IQR]) age, 58 [38–69] years), 48 (43.6%) had a good neurological outcome, time from ROSC to MRI scan was 2.8 h (IQR 2.0–4.0 h), and the PHSI on DW-MRI was observed in 46 (41.8%) patients. No patients in the PHSI group had a good neurological outcome compared with 48 (75%) patients in the AHSI group. In the AHSI group, cerebrospinal fluid (CSF) neuron-specific enolase (NSE) levels were significantly lower in the group with good neurological outcome compared to the group with poor neurological outcome (20.1 [14.4–30.7] ng/mL vs. 84.3 [32.4–167.0] ng/mL, P < 0.001). The area under the curve for PHSI on DW-MRI was 0.87 (95% confidence interval [CI] 0.80–0.93), and the specificity and sensitivity for predicting a poor neurological outcome were 100% (95% CI 91.2%–100%) and 74.2% (95% CI 62.0–83.5%), respectively. A higher sensitivity was observed when CSF NSE levels were combined (88.7% [95% CI 77.1–95.1%]; 100% specificity). Conclusions In this cohort study, PHSI findings on ultra-early DW-MRI were associated with poor neurological outcomes 6 months following the cardiac arrest. The combined CSF NSE levels showed higher sensitivity at 100% specificity than on DW-MRI alone. Prospective multicenter studies are required to confirm these results

The Usefulness of Quantitative Analysis of Blood-Brain Barrier Disruption Measured Using Contrast-Enhanced Magnetic Resonance Imaging to Predict Neurological Prognosis in Out-of-Hospital Cardiac Arrest Survivors: A Preliminary Study

We aimed to evaluate neurological outcomes associated with blood-brain barrier (BBB) disruption using contrast-enhanced magnetic resonance imaging (CE-MRI) in out-of-hospital cardiac arrest (OHCA) survivors. This retrospective observational study involved OHCA survivors who had undergone CE-MRI for prognostication. Qualitative and quantitative analyses were performed using the presence of BBB disruption (pBD) and the BBB disruption score (sBD) in CE-MRI scans, respectively. For the sBD, 1 point was assigned for each area of BBB disruption, and 6 points were assigned when an absence of intracranial blood flow due to severe brain oedema was confirmed. The primary outcome was poor neurological outcome at 3 months (defined as cerebral performance categories 3&ndash;5). We analysed 46 CE-MRI brain scans (27 patients). Of these, 15 (55.6%) patients had poor neurological outcomes. Poor neurological outcome group patients showed a significantly higher proportion of pBD than those in the good neurological outcome group (22 (88%) vs. 6 (28.6%) patients, respectively, p &lt; 0.001) and a higher sBD (5.0 (4.0&ndash;5.0) vs. 0.0 (0.0&ndash;1.0) patients, p &lt; 0.001). Poor neurological outcome predictions showed that the sBD had a significantly better prognostic performance (area under the curve (AUC) 0.95, 95% confidence interval (CI) 0.84&ndash;0.99) than the pBD (AUC 0.80, 95% CI 0.65&ndash;0.90). The sBD cut-off value was &gt;1 point (sensitivity, 96.0%; specificity, 81.0%). The sBD is a highly predictive and sensitive marker of 3-month poor neurological outcome in OHCA survivors. Multicentre prospective studies are required to determine the generalisability of these results

Distribution and elimination kinetics of midazolam and metabolites after post-resuscitation care: a prospective observational study

Abstract Administration of sedatives for post-resuscitation care can complicate the determination of the optimal timing to avoid inappropriate, pessimistic prognostications. This prospective study aimed to investigate the distribution and elimination kinetics of midazolam (MDZ) and its metabolites, and their association with awakening time. The concentrations of MDZ and its seven metabolites were measured immediately and at 4, 8, 12, and 24 h after the discontinuation of MDZ infusion, using liquid chromatography-tandem mass spectrometry. The area under the time-plasma concentration curve from 0 to 24 h after MDZ discontinuation (AUClast) was calculated based on the trapezoidal rule. Of the 15 enrolled patients, seven awakened after the discontinuation of MDZ infusion. MDZ and three of its metabolites were major compounds and their elimination kinetics followed a first-order elimination profile. In the multivariable analysis, only MDZ was associated with awakening time (AUClast: R2 = 0.59, p = 0.03; AUCinf: R2 = 0.96, p < 0.001). Specifically, a 0.001% increase in MDZ AUC was associated with a 1% increase in awakening time. In the individual regression analysis between MDZ concentration and awakening time, the mean MDZ concentration at awakening time was 16.8 ng/mL. The AUC of MDZ is the only significant factor associated with the awakening time

Does Combining Biomarkers and Brain Images Provide Improved Prognostic Predictive Performance for Out-Of-Hospital Cardiac Arrest Survivors before Target Temperature Management?

We examined whether combining biomarkers measurements and brain images early after the return of spontaneous circulation improves prognostic performance compared with the use of either biomarkers or brain images for patients with cardiac arrest following target temperature management (TTM). This retrospective observational study involved comatose out-of-hospital cardiac arrest survivors. We analyzed neuron-specific enolase levels in serum (NSE) or cerebrospinal fluid (CSF), grey-to-white matter ratio by brain computed tomography, presence of high signal intensity (HSI) in diffusion-weighted imaging (DWI), and voxel-based apparent diffusion coefficient (ADC). Of the 58 patients, 33 (56.9%) had poor neurologic outcomes. CSF NSE levels showed better prognostic performance (area under the curve (AUC) 0.873, 95% confidence interval (CI) 0.749&ndash;0.950) than serum NSE levels (AUC 0.792, 95% CI 0.644&ndash;0.888). HSI in DWI showed the best prognostic performance (AUC 0.833, 95% CI 0.711&ndash;0.919). Combining CSF NSE levels and HSI in DWI had better prognostic performance (AUC 0.925, 95% CI 0.813&ndash;0.981) than each individual method, followed by the combination of serum NSE levels and HSI on DWI and that of CSF NSE levels and the percentage of voxels of ADC (AUC 0.901, 95% CI 0.792&ndash;0.965; AUC 0.849, 95% CI 0.717&ndash;0.935, respectively). Combining CSF/serum NSE levels and HSI in DWI before TTM improved the prognostic performance compared to either each individual method or other combinations

Healthy lifestyle factors, cardiovascular comorbidities, and the risk of sudden cardiac arrest: A case-control study in Korea

© 2022 Elsevier B.V.Aims: We investigated the impact of healthy lifestyle factors and cardiovascular comorbidities for sudden cardiac arrest. Methods: A case-control study, including patients with sudden cardiac arrest aged 20–79 years and community-based 1:2 matched controls, was conducted from September 2017 to December 2020. All participants completed a structured questionnaire. Using multivariable logistic regression, we assessed cardiovascular comorbidities (diabetes, hypertension, dyslipidaemia, myocardial infarction, congestive heart failure, arrhythmia, and stroke) and healthy lifestyle factors (low red meat consumption, low fish consumption, high fruit consumption, high vegetable consumption, current non-smoking, regular exercise, and adequate sleep duration) as sudden cardiac arrest risk factors. Results: Among 3027 eligible cases, informed consent was obtained from 949 (31.3%) cases. A total of 1731 controls were enrolled. Cardiovascular comorbidities, except dyslipidaemia, were associated with an increased risk of sudden cardiac arrest, whereas all healthy lifestyle factors were associated with a decreased risk. Relative to patients in the 0–2 healthy lifestyle factors group, the adjusted odds ratio (95% confidence interval) for sudden cardiac arrest was 0.25 (0.16–0.40) in patients with 3 healthy lifestyle factors, 0.08 (0.05–0.13) in patients with 4 healthy lifestyle factors, and 0.04 (0.03–0.06) in patients with over 5 healthy lifestyle factors. When the number of healthy lifestyle factors was analysed as a continuous variable, each additional factor was associated with a significant decrease in the likelihood of sudden cardiac arrest (adjusted odds ratio [95% confidence interval]: 0.41 [0.36–0.46]). Conclusion: The increased risk of sudden cardiac arrest by cardiovascular comorbidities could be significantly reduced with healthy lifestyle factors.N