ABSTRACT
Perfusion Index is a non-invasive numerical value of peripheral perfusion [PI] obtained from pulse oximetery. Prognostic value of perfusion index and its relation to serum lactate and brain natriuretic peptide [BNP] changes has not been investigated in poly-traumatized patients. Fifty poly-traumatized adult patients with hemorrhagic shock without head injury were studied in a prospective observational study, perfusion index changes in relation to serum lactate, lactate clearance and Brain Natriuretic Peptide in survivors and non survivors and their predictability of mortality was evaluated. Full resuscitation according to the advanced trauma life support guidelines [ATLS] was carried out and the morbidity and mortality were followed up for 48 hours. Perfusion index was included as a target for peripheral perfusion and we compared its sensitivity and specificity with serum lactate and BNP for prediction of mortality. Statistical analysis was done using pearson's correlation and receiver operating curve [ROC]. Perfusion index showed a significant difference between survivors and non survivors after the first 6 hours post resuscitation [p < 0.001], ROC analysis showed that perfusion index /= 2.25 mmol/L provided the optimal cutoff point for predicting mortality with AUC was 0.57, sensitivity 79% and specificity 69%. Lactate clearance showed a significant difference between survivors and non survivors [p < 0.001], ROC curve analysis showed that lactate clearance < 3.0 mmol/L/24 hours provided the optimal cutoff point for predicting mortality with AUC was 0.97, sensitivity 97% and specificity 86%. Brain natriuretic peptide level at 48 hours [BNP-48] was significantly higher in non survivors than in survivors [p < 0.001]. ROC analysis showed that BNP-48 >/= 95.0 pg/ml provided the optimal cutoff point for predicting mortality with AUC was less than 0.5, sensitivity 61% and specificity 32%. Perfusion index is a good prognostic factor of mortality and lactate clearance seems the most accurate predictor of mortality as well. Serum lactate is the least accurate predictor of mortality followed by brain natriuretic peptide