BackgroundTraumatic brain-injured (TBI) patients suffer severe pain. The assessment of behavioral responses and vital signs seems to be necessary for pain detection in these patients, a matter that this study aims to evaluate.MethodsThis cross sectional study uses repeated measures and included ninety-seven TBI patients from Poorsina hospital, Rasht, Iran. Patients’ relevant parameters were recorded using demographic checklist, specifications related to the disease, RASS, CPOT, and FPT tools. The data subsequently were entered into SPSS software V. 21 and were analyze using several tests including Bonferroni’s inferential test and Greenhouse-Geisser test, multiple analysis regression coefficient and general linear model by GEE method.ResultsThe average age of patients was 42.3 ± 18.2. The average consciousness level was 9.30 ± 2.96. There was significant difference between the painful and non-painful stimulations in heart rate, systolic blood pressure and diastolic blood pressure (p <0.001). Heart rate (p < 0.001, r = 0.253), number of respiration (p < 0.001, r = 0.173), systolic (p = 0.002, r = 0.128) and diastolic (p<0.001, r=0.223) blood pressures had a positive correlation with behavioral responses. However, the arterial oxygen saturation showed a negative correlation with behavioral responses (p < 0.001, r = -0.361). Statistical models demonstrated a significant direct relationship between CPOT with heart rate (β = 2.39, p < 0.001) and both systolic blood pressure (β= 1.31, p=0.002) and the fluctuations of diastolic blood pressure (β = 0.690, p = 0.009). ConclusionIt seems that behavioral responses are appropriate indices for pain detection. However, vital signs are not capable of being considered as proper indexes for pain assessment since they changed during several procedures while remained unchanged in other tests.