Unmanned aerial vehicles (drones) in out-of-hospital-cardiac-arrest.

BACKGROUND: The use of an automated external defibrillator (AED) prior to EMS arrival can increase 30-day survival in out-of-hospital cardiac arrest (OHCA) significantly. Drones or unmanned aerial vehicles (UAV) can fly with high velocity and potentially transport devices such as AEDs to the site of OHCAs. The aim of this explorative study was to investigate the feasibility of a drone system in decreasing response time and delivering an AED. METHODS: Data of Global Positioning System (GPS) coordinates from historical OHCA in Stockholm County was used in a model using a Geographic Information System (GIS) to find suitable placements and visualize response times for the use of an AED equipped drone. Two different geographical models, urban and rural, were calculated using a multi-criteria evaluation (MCE) model. Test-flights with an AED were performed on these locations in rural areas. RESULTS: In total, based on 3,165 retrospective OHCAs in Stockholm County between 2006-2013, twenty locations were identified for the potential placement of a drone. In a GIS-simulated model of urban OHCA, the drone arrived before EMS in 32 % of cases, and the mean amount of time saved was 1.5 min. In rural OHCA the drone arrived before EMS in 93 % of cases with a mean amount of time saved of 19 min. In these rural locations during (n = 13) test flights, latch-release of the AED from low altitude (3-4 m) or landing the drone on flat ground were the safest ways to deliver an AED to the bystander and were superior to parachute release. DISCUSSION: The difference in response time for EMS between urban and rural areas is substantial, as is the possible amount of time saved using this UAV-system. However, yet another technical device needs to fit into the chain of survival. We know nothing of how productive or even counterproductive this system might be in clinical reality. CONCLUSIONS: To use drones in rural areas to deliver an AED in OHCA may be safe and feasible. Suitable placement of drone systems can be designed by using GIS models. The use of an AED equipped drone may have the potential to reduce time to defibrillation in OHCA.

Periodontal status of teeth facing extraction sites long-term after orthodontic treatment.

The present study was undertaken to examine the long-term periodontal status of teeth orthodontically moved into extraction sites. Patients were examined 14 to 34 years after active orthodontic treatment involving extraction of four first premolars. Three groups were established: one with closed tooth contacts and parallel adjacent teeth, one with closed tooth contacts and tipped adjacent teeth, and one with open contacts between adjacent teeth. Within each group accumulation of plaque, gingival health status, probing pocket depth, and probing attachment level of interproximal tooth surfaces, facing extraction sites and adjacent control sites between canine and lateral incisor were compared. Significantly more probing attachment loss was found in extraction sites with open tooth contacts (P less than 0.01) and with parallel adjacent teeth and closed tooth contacts (P less than 0.05) than in control sites. However, the mean differences were less than 0.5 mm, which may not be considered clinically significant. Tipping of teeth into the extraction sites had no long-term detrimental effect on the probing attachment level. No differences in accumulation of plaque and in gingival health status were observed.

Long-term effect of thin interdental alveolar bone on periodontal health after orthodontic treatment.

The present experiment was undertaken to determine if an interproximal area with a thin interdental bone septum following orthodontic treatment provides less resistance against marginal periodontal breakdown than an interproximal area with a normal width of bone between the roots. Only adult patients, at least 16 years after active orthodontic treatment, were studied. The distance between the roots was measured directly on periapical radiographs. Gingival health, level of attachment and bone level in sites with thin interdental bone were compared with neighboring or contralateral sites with a normal width of bone between the roots. No statistically significant differences in inflammation, level of attachment and clinical scores for bone level were observed. When measured radiographically the distance from the cementoenamel junction to the alveolar bone was significantly shorter in neighboring control sites (P less than 0.05). This discrepancy was most likely due to radiographic distortion. The results of this investigation suggest that in anterior areas marginal periodontal breakdown is unrelated to the thickness of bone between the roots. Too few molar sites were included to draw conclusions regarding such areas.

Rapidly progressive periodontitis. A distinct clinical condition.

We report radiographic, clinical, historical, and laboratory observations on seven patients selected to illustrate the features and characteristics of rapidly progressive periodontitis, with the aim of establishing this disease as a distinct clinical entity. This form of periodontitis is seen most commonly in young adults in their twenties, but it can occur in postpubertal individuals up to approximately 35 years of age. During the active phase, the gingival tissues are extremely inflamed and there is hemorrhage, proliferation of the marginal gingiva, and exudation. Destruction is very rapid, with loss of much of the alveolar bone occurring within a few weeks or months. This phase may be accompanied by general malaise, weight loss, and depression, although these symptoms are not seen in all patients. The disease may progress, without remission, to tooth loss, or alternatively, it may subside and become quiescent with or without therapy. The quiescent phase is characterized by the presence of clinically normal gingiva that may be tightly adapted to the roots of teeth with very advanced bone loss and deep periodontal pockets. The quiescent phase may be permanent, it may persist for an indefinite period, or the disease activity may return. Most patients with rapidly progressive periodontitis have serum antibodies specific for various species of Bacteroides, Actinobacillus, or both, and manifest defects in either neutrophil or monocyte chemotaxis. Affected patients generally respond favorably to treatment by scaling and open or closed curettage, especially when accompanied by standard doses of antibiotics for conventional time periods. A small minority of patients do not respond to any treatment, including antibiotics, and the disease progresses inexorably to tooth loss even in the presence of aggressive periodontal therapy and maintenance. At the present time it is not possible to distinguish prior to treatment which individuals will respond to therapy and which will not.

Variation of erythrocyte glutathione peroxidase activity in Finn sheep.

Erythrocyte glutathione peroxidase (GSH-Px) which was analysed on a flock of Finn sheep (266 sheep) showed variable activity despite the same diet and selenium intake. Mating experiments suggested that the GSH-Px activity was genetically determined. The low GSH-Px animals showed better performance as shown by a significantly reduced mortality rate of their offspring. Evidence of larger weight gain and wool production in the low GSH-Px sheep was obtained. The GSH-Px activity slightly decreased with age. The erythrocyte GSH-Px activity did not show much correlation with other genetical markers such as the potassium type, GSH type, haemoglobin type or sex. It is proposed that the low GSH-Px may represent an adaptation to low selenium intake.