Heart rate variability measurement in sepsis patients

Objectives: Inflammation makes an influence on autonomic nervous system and a change in autonomic nervous activity affects heart rate. Heart rate variability (HRV) test can quantify the autonomous nervous activity. In this study, we evaluated the meaning of heart rate variability in sepsis patients. Methods: Heart rate variability test was performed for sepsis patients and healthy volunteers. Normalised low frequency power, reflecting sympathetic activity, was compared to acute physiology and chronic health evaluation II (APACHE II) score and mortality in emergency department sepsis (MEDS) score in sepsis patients. Then the patients were divided into four groups: 1) severe sepsis patients, 2) sepsis patients admitted to general ward, 3) sepsis patients discharged within 24 hours and 4) healthy volunteers. We obtained averages for the HRV results in all four groups. The receiver operating characteristics curve was examined to determine whether or not HRV variables could be used to triage sepsis patients. Results: Correlations between normalised low frequency power (LFnu) with APACHE II score and MEDS score were -0.595 and -0.514, respectively. Low frequency power (LF) and LFnu values decreased in sepsis patients with the higher scores observed in the discharged sepsis patients and healthy volunteers. The areas under the curve for the values of LF and LFnu in the admission and discharge groups were 0.746 and 0.635, respectively (p<0.05). Conclusion: Variables related to heart rate variability are significantly correlated with the severity of sepsis patients. Although the HRV test alone cannot accurately predict the disposition of sepsis patients, in the emergency room setting it helps to assign beds to sepsis patients within the triage system, and avoid over-population.