Protracted pain is one main trigger of the devastating post-injury cascade reaction of complications and thus affects mortality probability. The level of pain can be registered by the life support provider at first contact in-field (point 1), and again on hospital admission (point 2). For this we use Visual Analogue Scales/VAS.
If the pain-2 is less than pain-1, prehospital treatment has been effective and we expect it to have increased the probability of survival. List VAS values at point1 and point 2 as continuous variables.