Decreased physiologic variability as a generalized response to human endotoxemia.
OBJECTIVE
To test the effect in normal human volunteers of transient systemic inflammation on the variability in time-series behaviors of widely divergent physiologic measures of the human inflammatory response.


METHODS
Prospective study of human volunteers who were tested on 2 consecutive days, a control day and a treatment day. Each participant served as his or her own control.


METHODS
Critical care facility of a university medical center.


METHODS
Subjects were eight healthy human volunteers.


METHODS
Participant subjects were tested on both a baseline day with no intervention and on a treatment day when they received 4 ng/kg intravenous Escherichia coli endotoxin.


RESULTS
Continuous electrocardiographic recordings and serial blood sampling (performed every 5 mins) were used to create time-series of heart rate (R-R intervals), neutrophil function (phagocytosis), and plasma cortisol concentrations. For each primary measure, we recorded a significant increase in the regularity (decreased variability) of the functional measurement as assessed by the statistical entity, approximate entropy.


CONCLUSIONS
Increased regularity, or decreased variability, of organ functions is a generalized response to systemic inflammation that occurs in widely divergent systems during endotoxemia.
Rassias
Athos J
AJ
Department of Anesthesiology, Dartmouth Medical School, Hanover, NH, USA.
Holzberger
Peter T
PT
Givan
Alice L
AL
Fahrner
Scott L
SL
Yeager
Mark P
MP
D000328:Adult; D001683:Biological Clocks; D019446:Endotoxemia / Q000503:physiopathology; D019277:Entropy; D005260:Female; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007249:Inflammation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D017711:Nonlinear Dynamics; D010587:Phagocytosis; D011446:Prospective Studies; D018805:Sepsis / Q000503:physiopathology*
D006854:Hydrocortisone