Slow-oscillatory tACS does not modulate human motor cortical response to repeated plasticity paradigms.

Previous history of activity and learning modulates synaptic plasticity and can lead to saturation of synaptic connections. According to the synaptic homeostasis hypothesis, neural oscillations during slow-wave sleep play an important role in restoring plasticity within a functional range. However, it is not known whether slow-wave oscillations-without the concomitant requirement of sleep-play a causal role in human synaptic homeostasis. Here, we aimed to answer this question using transcranial alternating current stimulation (tACS) to induce slow-oscillatory activity in awake human participants. tACS was interleaved between two plasticity-inducing interventions: motor learning, and paired associative stimulation (PAS). The hypothesis tested was that slow-oscillatory tACS would prevent homeostatic interference between motor learning and PAS, and facilitate plasticity from these successive interventions. Thirty-six participants received sham and active fronto-motor tACS in two separate sessions, along with electroencephalography (EEG) recordings, while a further 38 participants received tACS through a control montage. Motor evoked potentials (MEPs) were recorded throughout the session to quantify plasticity changes after the different interventions, and the data were analysed with Bayesian statistics. As expected, there was converging evidence that motor training led to excitatory plasticity. Importantly, we found moderate evidence against an effect of active tACS in restoring PAS plasticity, and no evidence of lasting entrainment of slow oscillations in the EEG. This suggests that, under the conditions tested here, slow-oscillatory tACS does not modulate synaptic homeostasis in the motor system of awake humans.

Absence of late gadolinium enhancement on cardiac magnetic resonance imaging in ventricular fibrillation and nonischemic cardiomyopathy.

INTRODUCTION: Cardiac magnetic resonance (CMR)-identified late gadolinium enhancement (LGE), representing regional fibrosis, is often used to predict ventricular arrhythmia risk in nonischemic cardiomyopathy (NICM). However, LGE is more closely correlated with sustained monomorphic ventricular tachycardia (SMVT) than ventricular fibrillation (VF). We characterized CMR findings of ventricular LGE in VF survivors. METHODS: We examined consecutively resuscitated VF survivors undergoing contrast-enhanced 1.5T CMR between 9/2007 and 7/2016. We excluded coronary artery disease, hypertrophic cardiomyopathy, amyloid, sarcoid, arrhythmogenic right ventricular cardiomyopathy, and channelopathy. Preexisting implantable cardioverter-defibrillator (ICD) was a CMR contraindication. VF patients were divided into three groups: (1) NICM, (2) left ventricular (LV) dilatation with normal LV ejection fraction (LVEF), and (3) normal LV size and LVEF. Two groups of NICM patients with and without SMVT were examined for comparison. RESULTS: We analyzed 87 VF patients, and found that LGE was seen in 8/22 (36%) with NICM (LVEF 38 ± 11%, LV end-diastolic volume index [LVEDVI] 134 ± 68 mL/BSA), 11/40 (28%) with LV dilatation and normal LVEF (LVEDVI 103 ± 17 mL/BSA), 4/25 (16%) with normal LV size and LVEF. Incidence of LGE in NICM patients without prior ventricular tachycardia/VF (LVEF 36 ± 12%, LVEDVI 141 ± 46 mL/body surface area [BSA]) was 117/277 and was not lower than those with VF and NICM (42% vs 36%; P = 0.59). By contrast, 22/37 NICM patients with SMVT (LVEF 42 ± 11%, LVEDVI 123 ± 48 mL/BSA) were LGE-positive (59% NICM-SMVT vs 36% NICM-VF; P = 0.04). CONCLUSION: Most VF survivors with a diagnosis of NICM did not have LGE on CMR and would not have met primary prevention ICD criteria based on LVEF. Absence of LGE may not portend a benign prognosis in NICM. Novel strategies for determining SCD risk in this cohort are required.

Interventions to manage occluded central venous access devices: An umbrella review.

The main objective of this umbrella review is to synthesise available evidence from systematic reviews on the effectiveness of interventions for the management of occlusions in central venous access devices. CVADS have been extensively utilised among the critically ill since the 1950s however have also been linked to an increase in catheter complications. CVAD occlusion can occur in 14%-36% of patients within 1-2 years of catheter placement and is a longstanding complication. Umbrella methodology was applied to review five healthcare databases. Databases were searched for publications from 2009 and 2022 and electronic keywords searches were conducted. The authors searched for reviews that reported on any intervention to prevent, maintain or manage patency of the central venous access devices within an acute care setting. Of the 278 articles identified from the initial search a total of 11 articles were identified. This umbrella review concluded that education enhances patient outcomes and decreases occlusion rates. Further studies are required to explore occlusion reduction strategies in relation to flushing and locking.

The threshold of rural placement frequency and duration: A repeated cross-sectional study examining rural career aspirations among student nurses.

AIM: This study aimed to explore what changes rural placement had on the perceptions of nursing students and the impact of placement frequency and duration on student considerations for rural practice. BACKGROUND: A strong rural healthcare workforce is a global concern and has led countries to look for creative ways to address this challenge. One approach is to train more health professionals, however, nursing students who grew up or lived in metropolitan or urbanised areas are suggested to be less inclined to pursue a rural career. As such it is posited that recurrent exposure to rural settings may exert a positive impact on future intention for rural practice. However, there is a need to explore the specific thresholds related to both the frequency and duration of rural placement exposure, as well as the cumulative impact multiple rural placements may have on the intention to engage in rural practice. DESIGN: A repeated cross-sectional design. METHODS: All nursing students from an Australian regional university were invited to complete an online questionnaire between 2019 and 2023. Demographic and placement specific questions were included. A modified version of the Nursing Community Apgar tool also measured the importance of key variables in rural career decision-making. Data were analysed using independent sample t-tests and one-way ANOVAs. Significance was determined at two-tailed p≤.05. RESULTS: Among the 835 respondents (response rate 15.4%), the average number and duration of rural placements was 2.45 placements and 3.01 weeks respectively. Rural placements did not have an impact on students who resided rurally or regionally. However, among metropolitan students who had experienced more than three rural placements, or more than sixteen cumulative weeks of placement, were significantly more likely to consider rural employment. Greater number of rural placements and longer cumulative duration had the greatest impact. CONCLUSION: Issues related to the nursing rural workforce are dynamic and complex. Understanding the unique drivers that improve the rural experiences among students, particularly metropolitan students, can have an impact on decision-making to pursue employment in rural environments. Importantly, whilst professional and clinical motivation and experiences are influential factors, the socialisation, environment and community features are essential elements that influence students' decisions to pursue a career in rural practice. Undertaking a nuanced approach that facilitates rural practice understanding among students may help shape future employment decision-making.

Exploring factors associated with failure of totally implanted vascular access devices in a regional and rural health service: a retrospective case-control study.

BACKGROUND: The assessment and management of totally implanted vascular access devices (TIVAD) prior to the administration of medications/fluids are vital to ensuring the risk of harm is mitigated. While numerous guidelines exist for the insertion and management of TIVAD, the level of evidence and external validity to support these guidelines is lacking. OBJECTIVES: The purpose of this study was to identify factors associated with suboptimal TIVAD placement and with failure of TIVAD. METHODS: A retrospective case-control study (n=80) was conducted at a regional hospital and health service in Australia. Binomial logistic regression analysis was performed using a backward selection approach to establish variables associated suboptimal TIVAD placement and with TIVAD failure. FINDINGS: Significant associations were identified between the patient's primary diagnosis and suboptimal TIVAD insertion. Specifically, a prior diagnosis of breast cancer was associated with a decreased probability of optimal TIVAD tip placement (OR=0.236 (95% CI 0.058 to 0.960), p=0.044). A statistically significant association between TIVAD failure and the log of the heparinised saline flush rate and rate of undocumented flushes was also established. Further research is needed to identify and assess whether modification of these variables improves initial totally implantable venous access ports placement and risk of subsequent failure.