An increase in heart rate variability can be an index for end point of resuscitation in trauma patients

PURPOSE: The measurement of heart rate variability (HRV) is a non-invasive method to analyze the balance of the autonomic nervous system. The aim of this study was to compare the changes of HRV and base deficit (BD) during the treatment of trauma patients. METHODS: Forty-three trauma patients with a low injury severity scores (ISS < 24) and negative base excess on admission were included in this study. Based on the BD changes, patients were divided into three groups: ‘end pointed’ group (n = 13), patients' BDs instantly cleared after primary hydration; ‘needs further resuscitation’ group (n = 21), patients' BDs did not reach the end point and thus required further hydration or packed red blood cells transfusion; and ‘hydration minimal change’ group (n = 9), patients' BDs lower than 2.5 mmol/L at the onset of admission and thereafter had minimal change (near normal range). The changes in HRV during fluid resuscitation were detected and compared to BD changes in their arterial blood gases. All data were analysed using the SPSS software Version 15.0. Repeated measures ANOVA was used to determine the changes in HRV, heart rate, blood pressure, and BD among groups. RESULTS: A significant reverse correlation was found between the BD ratio and the HRV ratio (r = −0.562; p = 0.01). The HRV of patients with aggravated BDs after fluid resuscitation was decreased. There was an increase in HRV at the time of BD clearance. A decrease in HRV after primary crystalloid hydration bore a significant connection with the need for an ICU (p = 0.021) and transfusion of packed red blood cells (p < 0.001). CONCLUSION: Increase in HRV may be a new non-invasive index for the end point of resuscitation in trauma patients.