What is the formula to calculate the Revised Trauma Score (RTS) using Glasgow Coma Scale (GCS) score, systolic blood pressure (SBP), and respiratory rate (RR)?

How to Calculate the Revised Trauma Score (RTS)

The Revised Trauma Score (RTS) is calculated by multiplying each coded value for Glasgow Coma Scale (GCS), systolic blood pressure (SBP), and respiratory rate (RR) by specific weighted factors (GCS: 0.9; SBP: 0.7; RR: 0.3) and then summing the results. 1

Formula and Calculation Process

The RTS calculation follows these steps:

1. Code the physiological parameters:

   • GCS: Assign a code value from 0-4
   • Systolic Blood Pressure (SBP): Assign a code value from 0-4
   • Respiratory Rate (RR): Assign a code value from 0-4

2. Apply the weighted formula:

   • RTS = (GCS code × 0.9) + (SBP code × 0.7) + (RR code × 0.3)

3. Coding values for each parameter:

   Parameter	Range	Code Value
   GCS	13-15	4
   	9-12	3
   	6-8	2
   	4-5	1
   	3	0
   SBP (mmHg)	>89	4
   	76-89	3
   	50-75	2
   	1-49	1
   	0	0
   RR (breaths/min)	10-29	4
   	>29	3
   	6-9	2
   	1-5	1
   	0	0

Clinical Significance and Applications

The RTS produces a score ranging from 0 to 7.8408, with higher scores indicating better prognosis. This score was developed in 1989 as a revision of the original Trauma Score 2.

While the RTS is valuable for outcome prediction and quality improvement purposes, it's important to note that:

• The complexity of calculating RTS makes it unwieldy for field triage decisions 1
• In practice, emergency medical services providers rarely calculate and use RTS as a real-time decision-making tool 1
• RTS is more appropriate for quality assurance and outcome measures than for emergency field work 1

Triage-RTS (T-RTS) Alternative

For field triage purposes, the simpler Triage-RTS (T-RTS) is often preferred:

• T-RTS = GCS code + SBP code + RR code (simple sum without weighting)
• Range: 0-12
• Easier to calculate in emergency situations 2

Recent research suggests that T-RTS may be equally effective for trauma outcome prediction compared to the weighted RTS, with the advantage of being simpler to calculate 3.

Limitations and Considerations

• The 2009 guidelines for field triage of injured patients noted that RTS was removed from the Decision Scheme due to its complexity and redundancy with individual physiological parameters already assessed 1
• More recent trauma scoring systems have been developed that may offer improved mortality prediction, such as the New Trauma Score (NTS) which incorporates peripheral oxygen saturation instead of respiratory rate 4
• When using RTS for research purposes, be aware that it's often confused with T-RTS in the literature 3

By understanding both the calculation method and appropriate applications of the RTS, clinicians can better utilize this tool for trauma outcome evaluation while recognizing its limitations for real-time decision making.