A Spatial Analysis of Incident Location and Prehospital Mortality for Two United Kingdom Helicopter Emergency Medical Services (HEMS)

Association of helicopter transportation and improved mortality for patients with major trauma in the northern French Alps trauma system: an observational study based on the TRENAU registry

“…From a public health perspective, a major goal of helicopter is to ensure equivalent outcomes for patients injured further from trauma centres compared to patients treated and transported by ground ambulance and injured in closer proximity to trauma centres. Miller et al suggested that helicopters reduce rural and urban disparity by providing access to distant area and deployment of advanced medical team [22]. In our study, overtriage was slightly increased.…”

“…Prehospital time from the first call to the arrival at hospital was longer in the helicopter group compared to the ground ambulance group, respectively median time 95 minutes and 85 [63-113] minutes (P < 0.001). Median transport time was similar between groups, 20 min [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] for helicopter and 21 min [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] for ground ambulance. Using multivariate logistic regression, helicopter was associated with reduced mortality compared to ground ambulance (adjusted OR 0.70; 95% CI, 0.53-0.92; P = 0.01) and with reduced undertriage (OR 0.69 95% CI, 0.60-0.80; P < 0.001).…”

Factors affecting development of air ambulance base: A systematic review and thematic analysis

“…However, according to studies, the geographical location and distance of the base of the accident site do not seem to be associated with an increase in mortality. [ 18 ] Climate and weather in each area, including temperature, humidity, altitude, and wind speed, are considered in selection of helicopter types and the development of air ambulance; 10% of missions of air ambulances around the world are canceled, because of bad weather conditions. This rate is even higher in Iran.…”

Shrinkage estimators of the spatial relative risk function

“…This constant could be absorbed into the tuning parameter, but only at the cost of making 𝜆 less easily interpretable.) It follows from (11) that the degree of shrinkage applied can be thought of in terms of changing the marks on 𝜆 observations at x. For example, if the raw kernel estimate is ρF (x) > 0, then shrinkage will have the effect of changing 𝜆 cases at x into controls, so long as this does not take the estimated log-relative risk below 0.…”

“…The point is that the global intensities can be examined directly from sample sizes, while examining differences in the spatial distributions is facilitated by the existence of the natural null value $$$ r=1 $$$, or $$$ \rho =0 $$$. Over the last 20 years, the spatial relative risk function has been applied to examples from many fields, including cross‐sectional studies in human and veterinary epidemiology; 8‐10 traffic accident analyses; 11 and ecological studies 12 . In many cases it is used for data visualization and exploratory modelling purposes.…”