Physiological severity descriptors

Notice that the impact of risk descriptors depends on the local context. E.g. people get “old” at different years-of-age in North and South.  Also the physiological capacity of a trauma patient is obviously different in well-fed Westerners and malnourished people. The coded values set in the RTS scoring system is based on studies of urban trauma in the US and may not fit rural scenarios in the South (PEKER). We therefore recommend registration also of the actual values of RR and BP.

Scientific studies document that the GCS is inaccurate due to inter-rater disagreement. We have therefore simplified scoring by substituting GCS values with plain ratings of consciousness level: awake =4, drowsy=3, coma reacts on sound=2, coma reacts on pain only=1, no reaction=0. See patient registry chart below (PEKER).

The physiological severity indicators in each and every patient vary by time, and should be registered at two points:

            When life support starts in-field                     On hospital (end-point) admission

            RR1                                                                RR2

            BP1                                                                BP2

            Level of consciousness 1                                  Level of consciousness 2

            RTS1 (coded)                                                   RTS2 (coded)

Anatomical severity descriptors

The RTS indicates the impact of the injury. But we also need a descriptor of the degree of tissue injury, how severe is the wound? For that, the Injury Severity Score/ISS is established as the standard international reference. The ISS score in the individual patient is defined from a comprehensive list of surgical diagnosis to be found in The Abbreviated Injury Scale (AIS) manual  (PEKER). If the actual patient has a penetrating chest injury and a compound femur fracture, you can find his ISS score from the list of diagnosis in the AIS manual:

“Fracture of 2 – 3 ribs with hemo/pneumothorax:             450220.3”

“Femur fracture open/displaced/comminuted:                  851801.3”

The injury severity is indicated by the figure after the dot, the AIS code. In this case the AIS code is “.3” for both diagnosis. ISS is then calculated as the sum of the squared AIS codes for the three most severe injuries. For our patient the ISS = 3x3 + 3x3 = 18. By tradition we regard ISS values <9 as “moderate”; ISS 9 – 15 as “serious”; and ISS > 15 as “major trauma victim”.

ISS can thus be used to characterize the overall severity of a population of patients, and to stratify (divide into subsets) the population for statistical analysis.