Premotor cortical beta synchronization and the network neuromodulation of externally paced finger tapping in Parkinson's disease.

Parkinson's disease (PD) is characterized by the disruption of repetitive, concurrent and sequential motor actions due to compromised timing-functions principally located in cortex-basal ganglia (BG) circuits. Increasing evidence suggests that motor impairments in untreated PD patients are linked to an excessive synchronization of cortex-BG activity at beta frequencies (13-30 Hz). Levodopa and subthalamic nucleus deep brain stimulation (STN-DBS) suppress pathological beta-band reverberation and improve the motor symptoms in PD. Yet a dynamic tuning of beta oscillations in BG-cortical loops is fundamental for movement-timing and synchronization, and the impact of PD therapies on sensorimotor functions relying on neural transmission in the beta frequency-range remains controversial. Here, we set out to determine the differential effects of network neuromodulation through dopaminergic medication (ON and OFF levodopa) and STN-DBS (ON-DBS, OFF-DBS) on tapping synchronization and accompanying cortical activities. To this end, we conducted a rhythmic finger-tapping study with high-density EEG-recordings in 12 PD patients before and after surgery for STN-DBS and in 12 healthy controls. STN-DBS significantly ameliorated tapping parameters as frequency, amplitude and synchrony to the given auditory rhythms. Aberrant neurophysiologic signatures of sensorimotor feedback in the beta-range were found in PD patients: their neural modulation was weaker, temporally sluggish and less distributed over the right cortex in comparison to controls. Levodopa and STN-DBS boosted the dynamics of beta-band modulation over the right hemisphere, hinting to an improved timing of movements relying on tactile feedback. The strength of the post-event beta rebound over the supplementary motor area correlated significantly with the tapping asynchrony in patients, thus indexing the sensorimotor match between the external auditory pacing signals and the performed taps. PD patients showed an excessive interhemispheric coherence in the beta-frequency range during the finger-tapping task, while under DBS-ON the cortico-cortical connectivity in the beta-band was normalized. Ultimately, therapeutic DBS significantly ameliorated the auditory-motor coupling of PD patients, enhancing the electrophysiological processing of sensorimotor feedback-information related to beta-band activity, and thus allowing a more precise cued-tapping performance.

Both stimulus-specific and configurational features of multiple visual stimuli shape the spatial ventriloquism effect.

Studies on multisensory perception often focus on simplistic conditions in which one single stimulus is presented per modality. Yet, in everyday life, we usually encounter multiple signals per modality. To understand how multiple signals within and across the senses are combined, we extended the classical audio-visual spatial ventriloquism paradigm to combine two visual stimuli with one sound. The individual visual stimuli presented in the same trial differed in their relative timing and spatial offsets to the sound, allowing us to contrast their individual and combined influence on sound localization judgements. We find that the ventriloquism bias is not dominated by a single visual stimulus but rather is shaped by the collective multisensory evidence. In particular, the contribution of an individual visual stimulus to the ventriloquism bias depends not only on its own relative spatio-temporal alignment to the sound but also the spatio-temporal alignment of the other visual stimulus. We propose that this pattern of multi-stimulus multisensory integration reflects the evolution of evidence for sensory causal relations during individual trials, calling for the need to extend established models of multisensory causal inference to more naturalistic conditions. Our data also suggest that this pattern of multisensory interactions extends to the ventriloquism aftereffect, a bias in sound localization observed in unisensory judgements following a multisensory stimulus.

Extra Nestlings That Are Condemned to Die Increase Reproductive Success in Hoopoes.

AbstractThe adaptive value of routinely laying more eggs than can be successfully fledged has intrigued evolutionary biologists for decades. Extra eggs could, for instance, be adaptive as insurance against hatching failures. Moreover, because recent literature demonstrates that sibling cannibalism is frequent in the Eurasian hoopoe (Upupa epops), producing extra offspring that may be cannibalized by older siblings might also be adaptive in birds. Here, directed to explore this possibility in hoopoes, we performed a food supplementation experiment during the laying period and a clutch size manipulation during the hatching stage. We found that females with the food supplement laid on average one more egg than control females and that the addition of a close-to-hatch egg at the end of the hatching period increased the intensity of sibling cannibalism and enhanced fledging success in hoopoe nests. Because none of the extra nestlings from the experimental extra eggs survived until fledging, these results strongly suggest that hoopoes obtain fitness advantages by using temporarily abundant resources to produce additional nestlings that will be cannibalized. These results therefore suppose the first experimental demonstration of the nutritive adaptive function of laying extra eggs in vertebrates with parental care.

Plant litter loss exacerbates drought influences on grasslands.

Plant litter is known to affect soil, community, and ecosystem properties. However, we know little about the capacity of litter to modulate grassland responses to climate change. Using a 7-yr litter removal experiment in a semiarid grassland, here we examined how litter removal interacts with a 2-yr drought to affect soil environments, plant community composition, and ecosystem function. Litter loss exacerbates the negative impacts of drought on grasslands. Litter removal increased soil temperature but reduced soil moisture and nitrogen mineralization, which substantially increased the negative impacts of drought on primary productivity and the abundance of perennial rhizomatous graminoids. Moreover, complete litter removal shifted plant community composition from grass-dominated to forb-dominated and reduced species and functional group asynchrony, resulting in lower ecosystem temporal stability. Our results suggest that ecological processes that lead to reduction in litter, such as burning, grazing, and haying, may render ecosystems more vulnerable and impair the capacity of grasslands to withstand drought events.

Buffering and phenological mismatch: A change of perspective.

The potential for climate change to disrupt phenology-mediated interactions in interaction networks has attracted considerable attention in recent decades. Frequently, studies emphasize the fragility of ephemeral seasonal interactions, and the risks posed by phenological asynchrony. Here, we argue that the fitness consequences of asynchrony in phenological interactions may often be more buffered than is typically acknowledged. We identify three main forms that buffering may take: (i) mechanisms that reduce asynchrony between consumer and resource; (ii) mechanisms that reduce the costs of being asynchronous; and (iii) mechanisms that dampen interannual variance in performance across higher organizational units. Using synchrony between the hatching of winter moth caterpillars and the leafing of their host-plants as a case study, we identify a wide variety of buffers that reduce the detrimental consequences of phenological asynchrony on caterpillar individuals, populations, and meta-populations. We follow this by drawing on examples across a breadth of taxa, and demonstrate that these buffering mechanisms may be quite general. We conclude by identifying key gaps in our knowledge of the fitness and demographic consequences of buffering, in the context of phenological mismatch. Buffering has the potential to substantially alter our understanding of the biotic impacts of future climate change-a greater recognition of the contribution of these mechanisms may reveal that many trophic interactions are surprisingly resilient, and also serve to shift research emphasis to those systems with fewer buffers and towards identifying the limits of those buffers.

Grassland degradation amplifies the negative effect of nitrogen enrichment on soil microbial community stability.

Although nitrogen (N) enrichment is known to threaten the temporal stability of aboveground net primary productivity, it remains unclear how it alters that of belowground microbial abundance and whether its impact can be regulated by grassland degradation. Using data from N enrichment experiments at temperate grasslands with no, moderate, severe, and extreme degradation degrees, we quantified the temporal stability of soil microbial abundance (hereafter 'microbial community stability') using the ratio of the mean quantitative PCR to its standard deviation over 4 years. Both bacterial and fungal community stability sharply decreased when N input exceeded 30 g N m-2 year-1 in non-degraded grasslands, whereas a reduction in this threshold occurred in degraded grasslands. Microbial species diversity, species asynchrony, and species associations jointly altered microbial community stability. Interestingly, the linkages between plant and microbial community stability were strengthened in degraded grasslands, suggesting that plants and soil microbes might depend on each other to keep stable communities in harsh environments. Our findings highlighted the importance of grassland degradation in regulating the responses of microbial community stability to N enrichment and provided experimental evidence for understanding the relationships between plant and microbial community stability.

Opposing responses of temporal stability of aboveground and belowground net primary productivity to water and nitrogen enrichment in a temperate grassland.

Changes in water and nitrogen availability, as important elements of global environmental change, are known to affect the temporal stability of aboveground net primary productivity (ANPP). However, evidences for their effects on the temporal stability of belowground net primary productivity (BNPP), and whether such effects are consistent between belowground and aboveground, are rather scarce. Here, we investigated the responses of temporal stability of both ANPP and BNPP to water and nitrogen addition based on a 9-year manipulative experiment in a temperate grassland in northern China. The results showed that the temporal stability of ANPP increased with water addition but decreased with nitrogen addition. By contrast, the temporal stability of BNPP decreased with water addition but increased with nitrogen enrichment. The temporal stability of ANPP was mainly determined by the soil moisture and inorganic nitrogen, which modulated species asynchrony, as well as by the stability of dominant species. On the other hand, the temporal stability of BNPP was mainly driven by the soil moisture and inorganic nitrogen that modulated ANPP of grasses, and by the direct effect of soil water availability. Our study provides the first evidence on the opposite responses of aboveground and belowground grassland temporal stability to increased water and nitrogen availability, highlighting the importance of considering both aboveground and belowground components of ecosystems for a more comprehensive understanding of their dynamics.

Temporal asynchrony of plant and soil biota determines ecosystem multifunctional stability.

The role of plant biodiversity in stabilizing ecosystem multifunctionality has been extensively studied; however, the impact of soil biota biodiversity on ecosystem multifunctional stability, particularly under multiple environmental changes, remains unexplored. By conducting an experiment with environmental changes (adding water and nitrogen to a long-term grazing experiment) and an experiment without environmental changes (an undisturbed site) in semi-arid grasslands, our research revealed that environmental changes-induced changes in temporal stability of both above- and belowground multifunctionality were mainly impacted by plant and soil biota asynchrony, rather than by species diversity. Furthermore, changes in temporal stability of above- and belowground multifunctionality, under both experiments with and without environmental changes, were mainly associated with plant and soil biota asynchrony, respectively, suggesting that the temporal asynchrony of plant and soil biota has independent and non-substitutable effects on multifunctional stability. Our findings emphasize the importance of considering both above- and belowground biodiversity or functions when evaluating the stabilizing effects of biodiversity on ecosystem functions.

Spatially heterogeneous shifts in vegetation phenology induced by climate change threaten the integrity of the avian migration network.

Phenological responses to climate change frequently vary among trophic levels, which can result in increasing asynchrony between the peak energy requirements of consumers and the availability of resources. Migratory birds use multiple habitats with seasonal food resources along migration flyways. Spatially heterogeneous climate change could cause the phenology of food availability along the migration flyway to become desynchronized. Such heterogeneous shifts in food phenology could pose a challenge to migratory birds by reducing their opportunity for food availability along the migration path and consequently influencing their survival and reproduction. We develop a novel graph-based approach to quantify this problem and deploy it to evaluate the condition of the heterogeneous shifts in vegetation phenology for 16 migratory herbivorous waterfowl species in Asia. We show that climate change-induced heterogeneous shifts in vegetation phenology could cause a 12% loss of migration network integrity on average across all study species. Species that winter at relatively lower latitudes are subjected to a higher loss of integrity in their migration network. These findings highlight the susceptibility of migratory species to climate change. Our proposed methodological framework could be applied to migratory species in general to yield an accurate assessment of the exposure under climate change and help to identify actions for biodiversity conservation in the face of climate-related risks.

Induction of subject-ventilator asynchrony by variation of respiratory parameters in a lung injury model in pigs.

BACKGROUND: Subject-ventilator asynchrony (SVA) was shown to be associated with negative clinical outcomes. To elucidate pathophysiology pathways and effects of SVA on lung tissue histology a reproducible animal model of artificially induced asynchrony was developed and evaluated. METHODS: Alterations in ventilator parameters were used to induce the three main types of asynchrony: ineffective efforts (IE), auto-triggering (AT), and double-triggering (DT). Airway flow and pressure, as well as oesophageal pressure waveforms, were recorded, asynchrony cycles were manually classified and the asynchrony index (AIX) was calculated. Bench tests were conducted on an active lung simulator with ventilator settings altered cycle by cycle. The developed algorithm was evaluated in three pilot experiments and a study in pigs ventilated for twelve hours with AIX = 25%. RESULTS: IE and AT were induced reliably and fail-safe by end-expiratory hold and adjustment of respiratory rate, respectively. DT was provoked using airway pressure ramp prolongation, however not controlled specifically in the pilots. In the subsequent study, an AIX = 28.8% [24.0%-34.4%] was induced and maintained over twelve hours. CONCLUSIONS: The method allows to reproducibly induce and maintain three clinically relevant types of SVA observed in ventilated patients and may thus serve as a useful tool for future investigations on cellular and inflammatory effects of asynchrony.

Mowing increased community stability in semiarid grasslands more than either fencing or grazing.

A substantial body of empirical evidence suggests that anthropogenic disturbance can affect the structure and function of grassland ecosystems. Despite this, few studies have elucidated the mechanisms through which grazing and mowing, the two most widespread land management practices, affect the stability of natural grassland communities. In this study, we draw upon 9 years of field data from natural grasslands in northern China to investigate the effects of gazing and mowing on community stability, specifically focusing on community aboveground net primary productivity (ANPP) and dominance, which are two major biodiversity mechanisms known to characterize community fluctuations. We found that both grazing and mowing reduced ANPP in comparison to areas enclosed by fencing. Grazing reduced community stability by increasing the likelihood of single-species dominance and decreasing the relative proportion of nondominant species. In contrast, mowing reduced the productivity of the dominant species but increased the productivity of nondominant species. As a consequence, mowing improved the overall community stability by increasing the stability of nondominant species. Our study provides novel insight into understanding of the relationship between community species fluctuation-stability, with implications for ecological research and ecosystem management in natural grasslands.

Population asynchrony within and between trophic levels have contrasting effects on consumer community stability in a subtropical lake.

Clarifying the effects of biodiversity on ecosystem stability in the context of global environmental change is crucial for maintaining ecosystem functions and services. Asynchronous changes between trophic levels over time (i.e. trophic community asynchrony) are expected to increase trophic mismatch and alter trophic interactions, which may consequently alter ecosystem stability. However, previous studies have often highlighted the stabilising mechanism of population asynchrony within a single trophic level, while rarely examining the mechanism of trophic community asynchrony between consumers and their food resources. In this study, we analysed the effects of population asynchrony within and between trophic levels on community stability under the disturbances of climate warming, fishery decline and de-eutrophication, based on an 18-year monthly monitoring dataset of 137 phytoplankton and 91 zooplankton in a subtropical lake. Our results showed that species diversity promoted community stability mainly by increasing population asynchrony both for phytoplankton and zooplankton. Trophic community asynchrony had a significant negative effect on zooplankton community stability rather than that of phytoplankton, which supports the match-mismatch hypothesis that trophic mismatch has negative effects on consumers. Furthermore, the results of the structural equation models showed that warming and top-down effects may simultaneously alter community stability through population dynamics processes within and between trophic levels, whereas nutrients act on community stability mainly through the processes within trophic levels. Moreover, we found that rising water temperature decreased trophic community asynchrony, which may challenge the prevailing idea that climate warming increases the trophic mismatch between primary producers and consumers. Overall, our study provides the first evidence that population and trophic community asynchrony have contrasting effects on consumer community stability, which offers a valuable insight for addressing global environmental change.

Arrival-breeding interval is flexible in a songbird and is not constrained by migration carry-over effects.

As spring phenology advances with climate change, so too must the timing of life cycle events. Breeding at the right time is critical in many species as it maximizes fitness. For long-distance migratory birds, flexibility in the duration of the arrival-breeding interval (pre-breeding period) may allow populations to adjust their timing of breeding. However, whether first egg-lay dates are flexible to local environmental conditions after arrival, and if they are constrained by the time needed to replenish energy lost during migration, remains unclear. We investigated the regional flexibility of the arrival-breeding interval in an avian migrant, the purple martin, Progne subis, across their breeding range. We evaluated whether the duration of the arrival-breeding interval was flexible to temperature and precipitation at breeding sites, and if timing was limited by migration rate and stopover duration. We also tested if longer interval durations were associated with higher fledging success. To address our hypotheses, we used a combination of migration tracking, weather and breeding data collected from four regions across eastern North America (26.1° N to 52.4° N latitude). We found the arrival-breeding interval to be shortest in the north and longest in the south. Across all regions, warmer temperatures encountered at breeding grounds were associated with shorter intervals, and faster migration rates led to longer intervals. The length of the interval was not influenced by precipitation or stopover duration. Finally, longer intervals were not associated with higher fledge success. Currently, the longer arrival-breeding intervals in this study system, on average 28.3 days, may provide both early and late-arriving birds with ample time for recovery so birds can lay eggs according to temperature. Any negative effects of faster migration may have been buffered by longer arrival-breeding intervals, as interval length did not determine fledge success. With ongoing climate change, further research is needed to examine if arrival-breeding intervals become constrained by migration timing, which may limit opportunities for migrants to match the timing of breeding with key resources.

Post-insufflation diaphragm contractions in patients receiving various modes of mechanical ventilation.

BACKGROUND: During mechanical ventilation, post-insufflation diaphragm contractions (PIDCs) are non-physiologic and could be injurious. PIDCs could be frequent during reverse-triggering, where diaphragm contractions follow the ventilator rhythm. Whether PIDCs happens with different modes of assisted ventilation is unknown. In mechanically ventilated patients with hypoxemic respiratory failure, we aimed to examine whether PIDCs are associated with ventilator settings, patients' characteristics or both. METHODS: One-hour recordings of diaphragm electromyography (EAdi), airway pressure and flow were collected once per day for up to five days from intubation until full recovery of diaphragm activity or death. Each breath was classified as mandatory (without-reverse-triggering), reverse-triggering, or patient triggered. Reverse triggering was further subclassified according to EAdi timing relative to ventilator cycle or reverse triggering leading to breath-stacking. EAdi timing (onset, offset), peak and neural inspiratory time (Tineuro) were measured breath-by-breath and compared to the ventilator expiratory time. A multivariable logistic regression model was used to investigate factors independently associated with PIDCs, including EAdi timing, amplitude, Tineuro, ventilator settings and APACHE II. RESULTS: Forty-seven patients (median[25%-75%IQR] age: 63[52-77] years, BMI: 24.9[22.9-33.7] kg/m2, 49% male, APACHE II: 21[19-28]) contributed 2 ± 1 recordings each, totaling 183,962 breaths. PIDCs occurred in 74% of reverse-triggering, 27% of pressure support breaths, 21% of assist-control breaths, 5% of Neurally Adjusted Ventilatory Assist (NAVA) breaths. PIDCs were associated with higher EAdi peak (odds ratio [OR][95%CI] 1.01[1.01;1.01], longer Tineuro (OR 37.59[34.50;40.98]), shorter ventilator inspiratory time (OR 0.27[0.24;0.30]), high peak inspiratory flow (OR 0.22[0.20;0.26]), and small tidal volumes (OR 0.31[0.25;0.37]) (all P ≤ 0.008). NAVA was associated with absence of PIDCs (OR 0.03[0.02;0.03]; P < 0.001). Reverse triggering was characterized by lower EAdi peak than breaths triggered under pressure support and associated with small tidal volume and shorter set inspiratory time than breaths triggered under assist-control (all P < 0.05). Reverse triggering leading to breath stacking was characterized by higher peak EAdi and longer Tineuro and associated with small tidal volumes compared to all other reverse-triggering phenotypes (all P < 0.05). CONCLUSIONS: In critically ill mechanically ventilated patients, PIDCs and reverse triggering phenotypes were associated with potentially modifiable factors, including ventilator settings. Proportional modes like NAVA represent a solution abolishing PIDCs.

The effects of real-time waveform analysis software on patient ventilator synchronization during pressure support ventilation: a randomized crossover physiological study.

BACKGROUND: Patient-ventilator asynchrony commonly occurs during pressure support ventilation (PSV). IntelliSync + software (Hamilton Medical AG, Bonaduz, Switzerland) is a new ventilation technology that continuously analyzes ventilator waveforms to detect the beginning and end of patient inspiration in real time. This study aimed to evaluate the physiological effect of IntelliSync + software on inspiratory trigger delay time, delta airway (Paw) and esophageal (Pes) pressure drop during the trigger phase, airway occlusion pressure at 0.1 s (P0.1), and hemodynamic variables. METHODS: A randomized crossover physiologic study was conducted in 14 mechanically ventilated patients under PSV. Patients were randomly assigned to receive conventional flow trigger and cycling, inspiratory trigger synchronization (I-sync), cycle synchronization (C-sync), and inspiratory trigger and cycle synchronization (I/C-sync) for 15 min at each step. Other ventilator settings were kept constant. Paw, Pes, airflow, P0.1, respiratory rate, SpO2, and hemodynamic variables were recorded. The primary outcome was inspiratory trigger and cycle delay time between each intervention. Secondary outcomes were delta Paw and Pes drop during the trigger phase, P0.1, SpO2, and hemodynamic variables. RESULTS: The time to initiate the trigger was significantly shorter with I-sync compared to baseline (208.9±91.7 vs. 301.4±131.7 msec; P = 0.002) and I/C-sync compared to baseline (222.8±94.0 vs. 301.4±131.7 msec; P = 0.005). The I/C-sync group had significantly lower delta Paw and Pes drop during the trigger phase compared to C-sync group (-0.7±0.4 vs. -1.2±0.8 cmH2O; P = 0.028 and - 1.8±2.2 vs. -2.8±3.2 cmH2O; P = 0.011, respectively). No statistically significant differences were found in cycle delay time, P0.1 and other physiological variables between the groups. CONCLUSIONS: IntelliSync + software reduced inspiratory trigger delay time compared to the conventional flow trigger system during PSV mode. However, no significant improvements in cycle delay time and other physiological variables were observed with IntelliSync + software. TRIAL REGISTRATION: This study was registered in the Thai Clinical Trial Registry (TCTR20200528003; date of registration 28/05/2020).

The effect of target detection task on memory encoding varies in different stimulus onset asynchronies.

The attentional boost effect (ABE) and action-induced memory enhancement (AIME) suggest that memory performance for target-paired items is superior to that for distractor-paired items when participants performed a target detection task and a memory encoding task simultaneously. Though the memory enhancement has been well established, the temporal dynamics of how the target detection task influenced memory encoding remains unclear. To investigate this, we manipulated the stimulus onset asynchrony (SOA) between detection stimuli and the words to be memorized using a remember/know study-test paradigm, and we focused primarily on memory performance for the words that appeared after the detection response. The results showed that target-paired memory enhancement was robust from SOA = 0 s to SOA = 0.75 s, but was not significant when examined by itself in Experiment 1A or weakened in Experiment 2 and the conjoint analysis when SOA = 1 s, which were only observed in R responses. The post-response memory enhancement still existed when there was no temporal overlap between the word and target, similar to the magnitude of memory enhancement observed with temporal overlap. These results supported the view that target-paired memory enhancement (recollection rather than familiarity) occurred irrespective of whether the items appeared simultaneously with the targets or within a short period after the response, and the temporal overlap of the word and target was not necessary for post-response memory enhancement.

Combined effects of heat waves and pesticide pollution on zooplankton communities: Does the timing of stressor matter?

Most studies assessing the combined effects of chemical and non-chemical stressors on aquatic ecosystems have been based on synchronous stressor applications. However, asynchronous exposure scenarios may be more common in nature, particularly for pulsed stressors such as heatwaves and pesticide concentration peaks. In this study, we investigated the single and combined effects of the insecticide chlorpyrifos (CPF) and a heatwave (HW) on a zooplankton community representative of a Mediterranean coastal wetland using synchronous (CPF+HW) and asynchronous (HW→CPF and CPF→HW) exposure scenarios. CPF was applied at a concentration of 0.8 µg/L (single pulse), and the HW was simulated by a temperature increase of 8°C above the control temperature (20°C) for 7 days in freshwater microcosms. The interaction between stressors in synchrony resulted in synergistic effects at the population level (Daphnia magna) and additive at the community level. The partial reduction of sensitive species resulted in an abundance increase of competing species that were more tolerant to the evaluated stressors (e.g. Moina sp.). The asynchronous exposure scenarios resulted in a similar abundance decline of sensitive populations as compared to the synchronous one; however, the timing of stressor resulted in different responses in the long term. In the HW→CPF treatment, the D. magna population recovered at least one month faster than in the CPF+HW treatment, probably due to survival selection and cross-tolerance mechanisms. In the CPF→HW treatment, the effects lasted longer than in the CPF+HW, and the population did not recover within the experimental period, most likely due to the energetic costs of detoxification and effects on internal damage recovery. The different timing and magnitude of indirect effects among the tested asynchronous scenarios resulted in more severe effects on the structure of the zooplankton community in the CPF→HW treatment. Our study highlights the relevance of considering the order of stressors to predict the long-term effects of chemicals and heatwaves both at the population and community levels.

Knowledge and associated factors of healthcare professionals in detecting patient-ventilator asynchrony using waveform analysis at intensive care units of the federal public hospitals in Addis Ababa, Ethiopia, 2023.

BACKGROUND: The interaction between the patient and the ventilator is often disturbed, resulting in patient-ventilator asynchrony (PVA). Asynchrony can lead to respiratory failure, increased artificial ventilation time, prolonged hospitalization, and escalated healthcare costs. Professionals' knowledge regarding waveform analysis has significant implications for improving patient outcomes and minimizing ventilation-related adverse events. Studies investigating the knowledge of healthcare professionals on patient-ventilator asynchrony and its associated factors in the Ethiopian context are limited. Therefore, this study aimed to assess the knowledge of healthcare professionals about using waveform analysis to detect asynchrony. METHODS: A multicenter cross-sectional study was conducted on 237 healthcare professionals (HCPs) working in the intensive care units (ICUs) of federal public hospitals in Addis Ababa, Ethiopia, from December 2022 to May 2023. The data were collected using a structured and pretested interviewer-administered questionnaire. Then, the collected data were cleaned, coded, and entered into Epi data V-4.2.2 and exported to SPSS V-27 for analysis. After description, associations were analyzed using binary logistic regression. Variables with a P-value of < 0.25 in the bivariable analysis were transferred to the multivariable analysis. Statistical significance was declared using 95% confidence intervals, and the strengths of associations were reported using adjusted odds ratios (AORs). RESULTS: A total of 237 HCPs participated in the study with a response rate of 100%. Half (49.8%) of the participants were females. The mean age of the participants was 29 years (SD = 3.57). Overall, 10.5% (95% CI: 6.9-15.2) of the participants had good knowledge of detecting PVA using waveform analysis. In the logistic regression, the number of MV-specific trainings and the training site had a statistically significant association with knowledge of HCPs. HCPs who attended more frequent MV training were more likely to have good knowledge than their counterparts [AOR = 6.88 (95% CI: 2.61-15.45)]. Additionally, the odds of good knowledge among professionals who attended offsite training were 2.6 times higher than those among professionals trained onsite [AOR = 2.63 (95% CI: 1.36-7.98)]. CONCLUSION: The knowledge of ICU healthcare professionals about the identification of PVA using waveform analysis is low. In addition, the study also showed that attending offsite MV training and repeated MV training sessions were independently associated with good knowledge. Consequently, the study findings magnify the relevance of providing frequent and specific training sessions focused on waveform analysis to boost the knowledge of HCPs.

Critical care nurses' knowledge and attitudes towards using ventilator waveform monitoring to detect patient-ventilator asynchrony: A cross-sectional online survey.

BACKGROUND: Patient-ventilator asynchrony (PVA) is a condition that commonly affects patients who are mechanically ventilated. PVA happens when the patient's own breathing effort and the ventilator preset settings are out of sync. Ventilator waveform monitoring is viewed as a difficult undertaking, even for experienced practitioners, despite being a non-invasive and reliable tool for diagnosing PVA. AIM: To assess the knowledge levels and attitudes of critical care nurses (CCNs) regarding the use of ventilator waveform monitoring to detect PVA. STUDY DESIGN: A cross-sectional online survey was conducted in three intensive care units (ICUs) in Alexandria, Egypt. The questionnaire consisted of four parts to evaluate CCNs' level of knowledge and attitude regarding ventilator waveform monitoring and assess their ability to detect PVA. RESULTS: Of the 137 CCNs approached, 101 CCNs completed the survey, resulting in a 73.7% response rate. Most nurses (88.1%) demonstrated poor knowledge levels and negative attitudes (93.1%) towards using waveform monitoring to detect PVA. A significant relationship was found between nurses' knowledge of ventilator waveform monitoring and their participation in previous training programmes on mechanical ventilation (MV; p = .031). Additionally, nurses' attitudes towards ventilator waveform monitoring were significantly associated with their level of education (p = .002) and attendance in previous courses on waveform analysis (p = .020). CONCLUSIONS: A majority of CCNs have poor knowledge and negative attitudes regarding ventilator waveform monitoring. Previous training in MV and attendance courses on ventilator waveform analysis showed a significant correlation between nurses' level of knowledge and attitudes regarding ventilator waveform monitoring. RELEVANCE TO CLINICAL PRACTICE: Assessment of CCNs' knowledge and attitudes regarding ventilator waveform monitoring for detecting patient-ventilator asynchrony (PVA) informs the development of future educational programmes, ultimately aiding in the delivery of prompt and high-quality care.

[A Review on Automatic Detection Algorithm for Patient-Ventilator Asynchrony during Mechanical Ventilation].

This study summarizes the application of automatic recognition technologies for patient-ventilator asynchrony (PVA) during mechanical ventilation. In the early stages, the method of setting rules and thresholds relied on manual interpretation of ventilator parameters and waveforms. While these methods were intuitive and easy to operate, they were relatively sensitive in threshold setting and rule selection and could not adapt well to minor changes in patient status. Subsequently, machine learning and deep learning technologies began to emerge and develop. These technologies automatically extract and learn data characteristics through algorithms, making PVA detection more robust and universal. Among them, logistic regression, support vector machines, random forest, hidden Markov models, convolutional autoencoders, long short-term memory networks, one-dimensional convolutional neural networks, etc., have all been successfully used for PVA recognition. Despite the significant advancements in feature extraction through deep learning methods, their demand for labelled data is high, potentially consuming significant medical resources. Therefore, the combination of reinforcement learning and self-supervised learning may be a viable solution. In addition, most algorithm validations are based on a single dataset, so the need for cross-dataset validation in the future will be an important and challenging direction for development.