## 2 Materials and Methods
### Trauma and Injury Severity Scoring for the Probability of Survival Prediction  
In the absence of a real trauma patient, the MIMIC database was used to calculate the trauma scores and it was used to calculate the survival prediction. Since the trauma scores were calculated using the vital signs (Numerics) and physiological parameters, it could be hypothesized that there may be a relationship between the trauma scores, the related physiological parameters and the prediction of survival. Statistical analysis was performed to derive the significance values for this relationship [47]. Once the relationship between the trauma and physiological parameter variables was confirmed, the readings from composite sensors could be used to calculate trauma scores and the prediction of survival in real time. This is imperative for patients who are under continuous monitoring for chronic illnesses, as they may suffer from episodes of trauma at any time. In order to perform multiparameter analysis using parameters like heart rate, pulse rate, temperature, oxygen saturation, and respiratory rate sensor readings from multiple sensors were gathered, and trauma related scores were calculated. Initially, NEWS calculations were performed using the following variables:  
* RR (breaths per minute) score
* PPG (%) score
* Any Supplemental Oxygen score (Yes/No)
* Temperature in \({}^{\circ}\)C (\({}^{\circ}\)F) scale
* Systolic BP score
* HR (beats per minute) score
* AVPU score  
NEWS score = Respiratory Rate score + Oxygen Saturation (%) score + Supplemental Oxygen score + Systolic BP score + Temperature scale + Heart Rate score + AVPU score  
In a real patient, the HR and RR would be derived from the ECG sensor, and the PPG sensor would provide an oxygen saturation reading. It was assumed that 'No' supplemental oxygen was provided, as the kit would be worn in non-hospitalized conditions. The AVPU score of '3' was assumed as the patient may not be alert and not fully conscious. A GCS score of 4 has been assumed with E1V1M2 responses. It can be noted that all the scores required to calculate the NEWS score could be obtained by the composite sensor kit. Following the NEWS score, the RTS was calculated using additional parameters. RTS, however, requires GCS scores. The Glasgow Coma Scale quantifies the severity of head injuries using motor/verbal responses, and uses following variables:  
* Best Motor Response (values: None to maximum 6)
* 6--Obeys command
* 5--Localizes pain
* 4--Normal withdrawal (flexion)
* 3--Abnormal withdrawal (flexion): decoricate
* 2--Abnormal withdrawal (extension): de-cerebrate None (flaccid)
* Best Verbal Response (values: None to maximum 5)
* 5--Oriented
* 4--Confused conversation
* 3--Inappropriate words
* 2--Incomprehensible sounds None
* Eye Opening (values: None to maximum 4)
* 4--Spontaneous
* 3--To speech
* 2--To pain None
* Calculation:
* GCS = Eye opening + Verbal response + Motor response = 4 (E1V1M2)  
The RTS is the most widely used prehospital field triage tool, and it was calculated using the following variables: The GCS score, the systolic blood pressure score, and the respiratory rate score. Calculation:  
RTS = Glasgow Coma Scale score + Systolic Blood Pressure score + Respiratory Rate score  
Interpretation: A lower score indicates a higher severity. RTS < 4 was proposed for transfer to a critical trauma centre. Following NEWS and RTS, the ISS had to be calculated. ISS is the first scoring system to be based on anatomic criteria, which defines the injury severity for comparative purposes. It was assumed that the ISS score was based on ICU-admitted patients' readings, so that an AIS score of 4 (severe) was chosen, resulting in ISS = 48. Trauma is measured using the TRISS scores. An important aspect of measuring trauma is to calculate the probability of survival. The Ps scores are measured as Ps blunt or Ps penetrating. Ps blunt indicates the probability of survival if the patient has suffered internal injuries.