| 1. |
- Andersson, Mathias H., et al.
(författare)
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Displacement effects of ship noise on fish population : FP7 - Collaborative Project n° 314227 WP 4: Sensitivity of marine life to shipping noise Task 4.2.1
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ship induced noise is one of the major contributors to the elevated noise levels in the world’s oceans today. However, the knowledge about the impact on marine organisms is still scarce. Especially the effects on fish behaviour needs to be studied as fish are a fundamental part of the oceans ecosystem. Direct measurement of fish behaviour in the open sea area is technically difficult but needs to be done in order to estimate reaction thresholds and scales of any reaction. This experiment studies the long term behavioural reaction by wild cod (Gadus morhua) to ship noise and describes the character and scale of the reaction. This study took place on the Swedish west coast with a small local cod population and the area is normally without any large vessel traffic. For the ship disturbance, the Swedish Coast Guard ship KBV 032 was hired and passed thru the area nine times during three days. During the three days of ship noise exposure, the noise levels increased well above the ambient noise. The ship signature was what could be expected in terms of spectral level with most radiated noise energy between 100 - 500 Hz. The ship had a higher source level than expected (232 dB re 1μPa at 1 m, 10 - 300 Hz) but this was deliberate as the crew was asked to use the propellers in a non-optimal way to generate as much noise as possible. The result was a lot of broadband cavitation pulses generated by the ship. Then a noise footprint model was created and used in the estimates of received levels (exposure level) by the individual fish in the area based on the most probable location. It was clear in the transmission loss varied between the two sites where at the shallow site, the noise was attenuated more compared to the deep site. This is probably caused by the quite complicated propagation pattern. Also, the acoustically different bottom properties will affect the transmission loss in the area. In total, 39 cod (Gadus morhua) were caught by hand jigging and were fitted with internal acoustical tags. Bottom mounted receivers were deployed covering the area where the cod were known to inhabit. This study was designed to capture more large scale movements of hundreds of meters and not startle responses to the ship noise. Out of the 39 tagged fish, 17 and 18 fish met the set quality criterion for the short time behaviour analysis and 23 fish for long time behaviour to be included in the analysis. Some fish met the quality criteria for both the short and long term analysis. The other fish were either eaten by seals, caught by fishermen, left the area or had a malfunctioning tag. In general, the noticed reaction in terms of horizontal swimming were much smaller than expected and what the study was designed for. This results was surprising as the sound pressure levels the fish were exposed to would, based on the literature, cause a strong behaviour response in the fish. The movement was not in any large scale that would affect their energy consumption and affect their long term survival. This study was able to track fish with an accuracy of less than 10 m and estimates an interval of received noise level. This is one of the first studies of its kind that is tracking free swimming fish over a long period of time during an acoustic disturbance.
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| 2. |
- Blom, Hans, et al.
(författare)
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Parallel Flow Measurements in Microstructures by Use of a Multifocal 4 x 1 Diffractive Optical Fan-Out Element
- 2002
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 41:31, s. 6614-6620
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a multifocal optical fluorescence correlation spectroscopy system for parallel flow analyses. Multifocal excitation was made possible through a 4 x 1 diffractive optical fan-out element, which produces uniform intensity in all four foci. Autocorrelation flow analyses inside a 20 μm x 20 μm square microchannel, with the 4 x 1 fan-out foci perpendicular to the flow direction, made it possible to monitor different flows in all four foci simultaneously. We were able to perform cross-correlation flow analyses by turning the microstructure, thereby having all four foci parallel to the direction of flow. Transport effects of the diffusion as a function of flow and distance could then also be studied.
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| 3. |
- Blom, Hans, et al.
(författare)
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Parallel Fluorescence Detection of Single Biomolecules in Microarrays by a Diffractive-Optical-Designed 2 x 2 Fan-Out Element
- 2002
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 41:16, s. 3336-3342
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a multifocal diffractive-optical fluorescence correlation spectroscopy system for parallel excitation and detection of single tetramethylrhodamine biomolecules in microarrays. Multifocal excitation was made possible through the use of a 2 × 2 fan-out diffractive-optical element with uniform intensity in all foci. Characterization of the 2 × 2 fan-out diffractive-optical element shows formation of almost perfect Gaussian foci of submicrometer lateral diameter, as analyzed by thermal motion of tetramethylrhodamine dye molecules in solution. Results of parallel excitation and detection in a high-density microarray of circular wells show single-biomolecule sensitivity in all four foci simultaneously.
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| 4. |
- Blom, Mathias, et al.
(författare)
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Associations between in-hospital bed occupancy and unplanned 72-h revisits to the emergency department: a register study.
- 2014
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Ingår i: International Journal of Emergency Medicine. - : Springer Science and Business Media LLC. - 1865-1380 .- 1865-1372. ; 7:Jun 28
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Tidskriftsartikel (refereegranskat)abstract
- A possible downstream effect of high in-hospital bed occupancy is that patients in the emergency department (ED) who would benefit from in-hospital care are denied admission. The present study aimed at evaluating this hypothesis through investigating associations between in-hospital bed occupancy at the time of presentation in the ED and the probability for unplanned 72-hour (72-h) revisits to the ED among patients discharged at index. A second outcome was unplanned 72-h revisits resulting in admission.
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| 5. |
- Blom, Mathias C., et al.
(författare)
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Primary triage nurses do not divert patients away from the emergency department at times of high in-hospital bed occupancy - a retrospective cohort study
- 2016
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Ingår i: BMC Emergency Medicine. - : Springer Science and Business Media LLC. - 1471-227X. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Emergency department (ED) overcrowding is frequently described in terms of input- throughput and output. In order to reduce ED input, a concept called primary triage has been introduced in several Swedish EDs. In short, primary triage means that a nurse separately evaluates patients who present in the Emergency Department (ED) and either refers them to primary care or discharges them home, if their complaints are perceived as being of low acuity. The aim of the present study is to elucidate whether high levels of in-hospital bed occupancy are associated with decreased permeability in primary triage. The appropriateness of discharges from primary triage is assessed by 72-h revisits to the ED. Methods: The study is a retrospective cohort study on administrative data from the ED at a 420-bed hospital in southern Sweden from 2011-2012. In addition to crude comparisons of proportions experiencing each outcome across strata of in-hospital bed occupancy, multivariate models are constructed in order to adjust for age, sex and other factors. Results: A total of 37,129 visits to primary triage were included in the study. 53.4 % of these were admitted to the ED. Among the cases referred to another level of care, 8.8 % made an unplanned revisit to the ED within 72 h. The permeability of primary triage was not decreased at higher levels of in-hospital bed occupancy. Rather, the permeability was slightly higher at occupancy of 100-105 % compared to <95 % (OR 1.09 95 % CI 1.02-1.16). No significant association between in-hospital bed occupancy and the probability of 72-h revisits was observed. Conclusions: The absence of a decreased permeability of primary triage at times of high in-hospital bed occupancy is reassuring, as the opposite would have implied that patients might be denied entry not only to the hospital, but also to the ED, when in-hospital beds are scarce.
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| 6. |
- Blom, Mathias Carl, et al.
(författare)
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Training machine learning models to predict 30-day mortality in patients discharged from the emergency department: A retrospective, population-based registry study
- 2019
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Ingår i: BMJ Open. - London : BMJ. - 2044-6055. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this work was to train machine learning models to identify patients at end of life with clinically meaningful diagnostic accuracy, using 30-day mortality in patients discharged from the emergency department (ED) as a proxy. Design Retrospective, population-based registry study. Setting Swedish health services. Primary and secondary outcome measures All cause 30-day mortality. Methods Electronic health records (EHRs) and administrative data were used to train six supervised machine learning models to predict all-cause mortality within 30 days in patients discharged from EDs in southern Sweden, Europe. Participants The models were trained using 65 776 ED visits and validated on 55 164 visits from a separate ED to which the models were not exposed during training. Results The outcome occurred in 136 visits (0.21%) in the development set and in 83 visits (0.15%) in the validation set. The model with highest discrimination attained ROC-AUC 0.95 (95% CI 0.93 to 0.96), with sensitivity 0.87 (95% CI 0.80 to 0.93) and specificity 0.86 (0.86 to 0.86) on the validation set. Conclusions Multiple models displayed excellent discrimination on the validation set and outperformed available indexes for short-term mortality prediction interms of ROC-AUC (by indirect comparison). The practical utility of the models increases as the data they were trained on did not require costly de novo collection but were real-world data generated as a by-product of routine care delivery.
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| 7. |
- Blom, Mathias
(författare)
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In-hospital bed occupancy and the emergency department - effects on decisions about the level of care
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Emergency Department (ED) overcrowding occurs when the need for ED services outstrips available resources. Causes have been divided into input, throughput, and output factors, of which the last appear to be the most influential. Unavailability of inpatient beds (so-called “access block,” or “hospital crowding”) impairs ED output and is associated with increased waiting times in the ED, especially for patients awaiting hospital admission (“boarding”). Access block has also been suspected to induce an admission-bias, causing only the sickest patients to be admitted to hospital when hospital beds are scarce. The aim of this thesis was to evaluate whether access block affected the prioritization of the level of care in ED patients so that patients were less likely to be admitted to a hospital bed at times of access block than otherwise. Part V addressed whether more patients were triaged out of the ED at times of access block. Methods: In Part I, the proportion of hospital admissions among 118,668 visits to the ED, at a 420-bed emergency hospital in Region Skåne, Sweden, was compared across different levels of access block (measured as strata of in-hospital bed occupancy). Multivariate models were constructed to adjust for the effects of known confounders. In Part II, the appropriateness of ED discharges was addressed by comparing the proportion of unplanned 72h revisits to the ED across different levels of access block, for the 81,878 cases treated and released from the ED at index. In Part III, the outcomes evaluated in Parts I and II were addressed for 19,620 ED visits due to acute abdominal pain. Part IV was performed analogously to Part III, but for 12,223 ED visits due to chest pain. In Part V, the permeability of an ED front-end facility that triages patients of perceived low acuity out of the ED was compared across different levels of access block, for 37,129 visits to the facility. Results: In Part I, a negative association between access block and the probability of inpatient admission was observed (OR 0.67–0.81 at occupancy >105%, compared to at occupancy <95%), implying that patients were less likely to be admitted to the hospital at times of access block. Part II revealed no association between access block and the 72h revisit rate. The association detected in Part I remained for the study populations addressed in Parts III/IV. No association between access block and the 72h revisit rate was observed in patients with acute abdominal pain, but a negative association between the two was observed in patients with chest pain. ED length of stay in patients who were treated and released from the ED increased at times of access block, in Parts III/IV. Conclusion: ED patients were less likely to be admitted to a hospital bed at times of access block than otherwise, at the study site. The lack of an association with the 72h revisit rate could be interpreted as that the practice is safe, but since it fails to take into account rare, but fatal, outcomes such as mortality, future studies should address more granular patient outcomes and specific subgroups. Cost-effectiveness analysis could help to evaluate the viability of managing certain conditions in the ED as compared to in inpatient wards.
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| 8. |
- Blom, Mathias, et al.
(författare)
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Patients presenting at the emergency department with acute abdominal pain are less likely to be admitted to inpatient wards at times of access block: a registry study.
- 2015
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Ingår i: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. - : Springer Science and Business Media LLC. - 1757-7241. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Also known as access block, shortage of inpatient beds is a common cause of emergency department (ED) boarding and overcrowding, which are both associated with impaired quality of care. Recent studies have suggested that access block not simply causes boarding in EDs, but may also result in that patients are less likely to be admitted to the hospital from the ED. The present study's aim was to investigate whether this effect remained for patients with acute abdominal pain, for which different management strategies have emerged. Access block was defined in terms of hospital occupancy and the appropriateness of ED discharges addressed as 72 h revisits to the ED.
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| 9. |
- Blom, Mathias, et al.
(författare)
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The probability of patients being admitted from the emergency department is negatively correlated to in-hospital bed occupancy - a registry study.
- 2014
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Ingår i: International Journal of Emergency Medicine. - : Springer Science and Business Media LLC. - 1865-1380 .- 1865-1372. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- The association between emergency department (ED) overcrowding and poor patient outcomes is well described, with recent work suggesting that the phenomenon causes delays in time-sensitive interventions, such as resuscitation. Even though most researchers agree on the fact that admitted patients boarding in the ED is a major contributing factor to ED overcrowding, little work explicitly addresses whether in-hospital occupancy is associated to the probability of patients being admitted from the ED. The objective of the present study is to investigate whether such an association exists.
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| 10. |
- Blom, Mathias, et al.
(författare)
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The probability of readmission within 30 days of hospital discharge is positively associated with inpatient bed occupancy at discharge - a retrospective cohort study.
- 2015
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Ingår i: BMC Emergency Medicine. - : Springer Science and Business Media LLC. - 1471-227X. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Previous work has suggested that given a hospital's need to admit more patients from the emergency department (ED), high inpatient bed occupancy may encourage premature hospital discharges that favor the hospital's need for beds over patients' medical interests. We argue that the effects of such action would be measurable as a greater proportion of unplanned hospital readmissions among patients discharged when the hospital was full than when not. In response, the present study tested this hypothesis by investigating the association between inpatient bed occupancy at the time of hospital discharge and the 30-day readmission rate.
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