Heart rate variability in emergency department patients with sepsis.

OBJECTIVE To test the hypothesis that heart rate variability (HRV) can provide an early indication of illness severity among patients presenting to the emergency department (ED) with sepsis. METHODS The authors enrolled a convenience sample of 15 ED patients meeting the American College of Chest Physicians/Society of Critical Care Medicine criteria for sepsis. Each patient had continuous Holter monitoring performed in the ED. Acute Physiology and Chronic Health II (APACHE II) and Sequential Organ Failure (SOFA) scores were calculated for the day of presentation. Holter tapes obtained in the ED were analyzed off-line to calculate HRV variables for the 5-minute segment with the least artifact and non-sinus beats. These variables were correlated with APACHE II and SOFA scores. RESULTS LFnu (normalized low-frequency power), an assessment of the relative sympathetic contribution to overall HRV, was correlated with increased illness severity as calculated using APACHE II (r = -0.67, r(2) = 0.43) and SOFA (r = -0.80, r(2) = 0.64) scores. LF/HF ratio (low-frequency/high-frequency ratio), a measure of sympathovagal balance, was correlated with the SOFA score [r = -0.54 (95% CI = -0.83 to -0.01), r(2) = 0.29]. All five patients who required critical care monitoring or ventilatory support or who died during the first 5 days of their hospitalization had LFnu values below 0.5 and LF/HF ratios less than 1.0. None of the patients with measurements greater than these threshold values died or required these interventions during the five days following admission. CONCLUSIONS A single variable, LFnu, which reflects sympathetic modulation of heart rate, accounted for 40-60% of the variance in illness severity scores among patients presenting to the ED with sepsis. HRV, as reflected in LFnu and the LF/HF ratio and measured with a single brief (5-minute) period of monitoring while in the ED, may provide the emergency physician with a readily available, noninvasive, early marker of illness severity. The threshold effect of LFnu and LF/HF in the prediction of early clinical deterioration was an unexpected finding and should be regarded as hypothesis-generating, pending further study.

[1]  A. Burger,et al.  Circadian patterns of heart rate variability in normals, chronic stable angina and diabetes mellitus. , 1999, International journal of cardiology.

[2]  H. Nguyen,et al.  Critical care in the emergency department: A physiologic assessment and outcome evaluation. , 2000, Academic emergency medicine : official journal of the Society for Academic Emergency Medicine.

[3]  Urs E. Ruttimann,et al.  Decomplexification in critical illness and injury: Relationship between heart rate variability, severity of illness, and outcome , 1998, Critical care medicine.

[4]  S. Lowry,et al.  An overview of mortality risk prediction in sepsis. , 1995, Critical care medicine.

[5]  K. Ferguson,et al.  Bacteremia and sepsis. , 1996, Emergency medicine clinics of North America.

[6]  D. Karras,et al.  Endogenous mediators in emergency department patients with presumed sepsis: are levels associated with progression to severe sepsis and death? , 2000, Annals of emergency medicine.

[7]  T G Buchman,et al.  Experimental human endotoxemia increases cardiac regularity: results from a prospective, randomized, crossover trial. , 1996, Critical care medicine.

[8]  M. S. Rangel-Frausto,et al.  The epidemiology of bacterial sepsis. , 1999, Infectious disease clinics of North America.

[9]  E. Rivers,et al.  The clinical utility of serologic markers in the evaluation of the acute scrotum. , 2000, Academic emergency medicine : official journal of the Society for Academic Emergency Medicine.

[10]  G. Breithardt,et al.  Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. , 1996 .

[11]  W. Shoemaker,et al.  Early physiologic patterns in acute illness and accidents: toward a concept of circulatory dysfunction and shock based on invasive and noninvasive hemodynamic monitoring. , 1996, New horizons.

[12]  T G Buchman,et al.  Uncoupling of biological oscillators: a complementary hypothesis concerning the pathogenesis of multiple organ dysfunction syndrome. , 1996, Critical care medicine.

[13]  P. Peterson,et al.  Severe sepsis in the emergency department and its association with a complicated clinical course. , 1998, Academic emergency medicine : official journal of the Society for Academic Emergency Medicine.

[14]  D Annane,et al.  Cardiac variability in critically ill adults: Influence of sepsis , 2001, Critical care medicine.

[15]  S. Opal.  The uncertain value of the definition for SIRS. Systemic inflammatory response syndrome. , 1998, Chest.

[16]  G. Slotman,et al.  MULTIVARIATE REGRESSION MODELING FOR THE PREDICTION OF INFLAMMATION, SYSTEMIC PRESSURE, AND END‐ORGAN FUNCTION IN SEVERE SEPSIS , 1997, Shock.

[17]  M. Rady.  The role of central venous oximetry, lactic acid concentration and shock index in the evaluation of clinical shock: a review. , 1992, Resuscitation.

[18]  B. Goldstein,et al.  Heart Rate Variability in Intensive Care , 1998 .

[19]  W. Knaus,et al.  Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. , 1992, Chest.

[20]  R. Bone.  The sepsis syndrome. Definition and general approach to management. , 1996, Clinics in chest medicine.

[21]  B. A. Boucher,et al.  Searching for simple outcome markers in sepsis: an effort in futility? , 1999, Critical Care Medicine.

[22]  Yoshimitsu Yamasaki,et al.  Diurnal heart rate variability in healthy subjects: effects of aging and sex difference. , 1996, The American journal of physiology.

[23]  D Annane,et al.  Inappropriate sympathetic activation at onset of septic shock: a spectral analysis approach. , 1999, American journal of respiratory and critical care medicine.

[24]  D H Singer,et al.  Heart Rate Variability , 1992 .

[25]  A. Malliani,et al.  Heart rate variability. Standards of measurement, physiological interpretation, and clinical use , 1996 .

[26]  P. Marik,et al.  Severity scoring and outcome assessment. Computerized predictive models and scoring systems. , 1999, Critical care clinics.

[27]  T B Kuo,et al.  Spectral analysis of systemic arterial pressure and heart rate signals as a prognostic tool for the prediction of patient outcome in the intensive care unit. , 1997, Critical care medicine.

[28]  M. Rady.  TRIAGE OF CRITICALLY ILL PATIENTS: An Overview of Interventions , 1996 .

[29]  P. Parsons,et al.  Early detection and markers of sepsis. , 1996, Clinics in chest medicine.

[30]  W. Knaus,et al.  APACHE II: a severity of disease classification system. , 1985 .

[31]  T G Buchman,et al.  Awash in data: the problem of predicting physiology in severe sepsis. , 1997, Shock.

[32]  G. Moore.  Ethics seminars: the practice of medical procedures on newly dead patients--is consent warranted? , 2001, Academic emergency medicine : official journal of the Society for Academic Emergency Medicine.

[33]  K. Tracey,et al.  Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin , 2000, Nature.

[34]  D. Toweill,et al.  Linear and nonlinear dynamics and the pathophysiology of shock. , 1998, New horizons.

[35]  D. Hoyt,et al.  Spectral analysis of heart rate variability in the ICU: a measure of autonomic function. , 1996, The Journal of surgical research.

[36]  M. H. Kempski,et al.  Autonomic modulation of heart rate variability during endotoxin shock in rabbits. , 1995, Critical care medicine.