Characteristics of Heart Rate Variability Can Predict Impending Septic Shock in Emergency Department Patients with Sepsis

OBJECTIVES: To determine whether heart rate variability (HRV) measures can be used to predict which septic patients in the emergency department (ED) will progress to septic shock. METHODS: The authors prospectively enrolled consecutive patients who met the 2001 International Sepsis Definitions Conference criteria of sepsis and visited the ED of a university teaching hospital over a six-month period. In addition to the septic workup, a continuous 10-minute electrocardiogram recording was performed at the same time. The HRV measures were calculated off-line and correlated with the outcome of the patients. RESULTS: Eighty-one patients aged 30-84 years who met the inclusion criteria were enrolled. The patients were classified as those with no septic shock (n = 60) and those with septic shock (n = 21), according to their outcome within six hours. The baseline root mean square successive difference, high-frequency power, and normalized high-frequency power of the septic shock group were significantly higher than those of the no septic shock group. The low-frequency power, normalized low-frequency power, and low-/high-frequency power ratio of the septic shock group were significantly lower than those of the no septic shock group. Multiple logistic regression analysis identified root mean square successive difference as the best predictor of impending septic shock for septic ED patients. CONCLUSIONS: HRV measures may be used to identify septic ED patients with impending septic shock. Among those HRV measures, root mean square successive difference seems to be the best indicator to predict the occurrence of septic shock.