Temporal trends of ambulance time intervals for suspected stroke/transient ischaemic attack (TIA) before and during the COVID-19 pandemic in Ireland: a quasi-experimental study.

OBJECTIVES: Time is a fundamental component of acute stroke and transient ischaemic attack (TIA) care, thus minimising prehospital delays is a crucial part of the stroke chain of survival. COVID-19 restrictions were introduced in Ireland in response to the pandemic, which resulted in major societal changes. However, current research on the effects of the COVID-19 pandemic on prehospital care for stroke/TIA is limited to early COVID-19 waves. Thus, we aimed to investigate the effect of the COVID-19 pandemic on ambulance time intervals and suspected stroke/TIA call volume for adults with suspected stroke and TIA in Ireland, from 2018 to 2021. DESIGN: We conducted a secondary data analysis with a quasi-experimental design. SETTING: We used data from the National Ambulance Service in Ireland. We defined the COVID-19 period as '1 March 2020-31 December 2021' and the pre-COVID-19 period '1 January 2018-29 February 2020'. PRIMARY AND SECONDARY OUTCOME MEASURES: We compared five ambulance time intervals: 'allocation performance', 'mobilisation performance', 'response time', 'on scene time' and 'conveyance time' between the two periods using descriptive and regression analyses. We also compared call volume for suspected stroke/TIA between the pre-COVID-19 and COVID-19 periods using interrupted time series analysis. PARTICIPANTS: We included all suspected stroke/TIA cases ≥18 years who called the National Ambulance Service from 2018 to 2021. RESULTS: 40 004 cases were included: 19 826 in the pre-COVID-19 period and 19 731 in the COVID-19 period. All ambulance time intervals increased during the pandemic period compared with pre-COVID-19 (p<0.001). Call volume increased during the COVID-19-period compared with the pre-COVID-19 period (p<0.001). CONCLUSIONS: A 'shock' like a pandemic has a negative impact on the prehospital phase of care for time-sensitive conditions like stroke/TIA. System evaluation and public awareness campaigns are required to ensure maintenance of prehospital stroke pathways amidst future healthcare crises. Thus, this research is relevant to routine and extraordinary prehospital service planning.

Dynamic occupancy modeling of temperate marine fish in area-based closures.

Species distribution models (SDMs) are commonly used to model the spatial structure of species in the marine environment, however, most fail to account for detectability of the target species. This can result in underestimates of occupancy, where nondetection is conflated with absence. The site occupancy model (SOM) overcomes this failure by treating occupancy as a latent variable of the model and incorporates a detection submodel to account for variability in detection rates. These have rarely been applied in the context of marine fish and never for the multiseason dynamic occupancy model (DOM). In this study, a DOM is developed for a designated species of concern, cusk (Brosme brosme), over a four-season period. Making novel use of a high-resolution 3-dimensional hydrodynamic model, detectability of cusk is considered as a function of current speed and algae cover. Algal cover on the seabed is measured from video surveys to divide the study area into two distinct regions: those with canopy forming species of algae and those without (henceforth bottom types). Modeled estimates of the proportion of sites occupied in each season are 0.88, 0.45, 0.74, and 0.83. These are significantly greater than the proportion of occupied sites measured from underwater video observations which are 0.57, 0.28, 0.43, and 0.57. Individual fish are detected more frequently with increasing current speed in areas lacking canopy and less frequently with increasing current speed in areas with canopy. The results indicate that, where possible, SDM studies for all marine species should take account of detectability to avoid underestimating the proportion of sites occupied at a given study area. Sampling closed areas or areas of conservation often requires the use of nonphysical, low impact sampling methods like camera surveys. These methods inherently result in detection probabilities less than one, an issue compounded by time-varying features of the environment that are rarely accounted for marine studies. This work highlights the use of modeled hydrodynamics as a tool to correct some of this imbalance.

Trace metal contamination of Beaufort's Dyke, North Channel, Irish Sea: a legacy of ordnance disposal.

Beaufort's Dyke is a disused ordnance disposal ground within the North Channel of the Irish Sea. Over 1 million tonnes of ordnance were disposed of in the dyke over a 40 year period representing a substantial volume of trace metal pollutants introduced to the seabed. Utilising particle transport modelling software we simulated the potential transport of metal particles from Beaufort's Dyke over a 3 month period. This demonstrated that Beaufort's Dyke has the potential to act as a source for trace metal contamination to areas beyond the submarine valley. Trace metal analysis of sediments from the Dyke and surrounding National Marine Monitoring Programme areas demonstrate that the Dyke is not the most contaminated site in the region. Particle transport modelling enables the transport pathways of trace metal contaminants to be predicted. Implementation of the technique in other munitions disposal grounds will provide valuable information for the selection of monitoring stations.