title: Is early clinical evidence of autonomic shift predictive of infection after aneurysmal subarachnoid hemorrhage.
abstract: BACKGROUND
  Autonomic shift (AS), characterized by increased sympathetic nervous system activation, has been implicated in neurologically mediated cardiopulmonary dysfunction and immunodepression after stroke. We investigated the prevalence of AS defined by readily available clinical parameters and determined the association of AS with subsequent infection in a cohort of patients with aneurysmal subarachnoid hemorrhage (aSAH).
  
  
  METHODS
  Data were obtained from a single-center cohort study of aSAH patients admitted from January 1, 2007, through April 1, 2012. AS was defined as at least 1 early (<72 hours) routine clinical marker of neurologically mediated cardiopulmonary dysfunction based on electrocardiogram, echocardiogram, cardiac enzymes, or neurogenic pulmonary edema. Multivariable logistic regression models were developed to evaluate the association between AS and subsequent infection after adjusting for other covariates.
  
  
  RESULTS
  A total of 167 patients were included in the analysis (mean age 56, 27% men). AS was seen in 66 of 167 patients (40%; 95% confidence interval [CI], 32%-47%), and infection was seen in 80 of 167 patients (48%; 95% CI, 40%-55%). AS was associated with subsequent infection on unadjusted analysis (odds ratio [OR] 2.11; 95% CI, 1.12-3.97); however, this association was no longer significant when adjusting for other predictors of infection (OR 1.36; 95% CI, .67-2.76). Age, clinical grade, and aneurysm location were all independent predictors of infection after aSAH.
  
  
  CONCLUSIONS
  We identified AS based on readily available clinical markers in 40% of patients with aSAH, though AS defined by these clinical criteria was not an independent predictor of infection. Additional studies may be warranted to determine the optimal definition of AS and the clinical significance of this finding.
authors.affiliation: Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan; Stroke Program, University of Michigan Medical School, Ann Arbor, Michigan. Electronic address: jeffletc@med.umich.edu.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Fletcher
authors.affiliation: Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan.
authors.forename: Venkatakrishna
authors.initials: V
authors.lastname: Rajajee
authors.affiliation: Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wilson
authors.affiliation: Stroke Program, University of Michigan Medical School, Ann Arbor, Michigan.
authors.forename: Darin B
authors.initials: DB
authors.lastname: Zahuranec
mesh_terms: D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D001424:Bacterial Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013997:Time Factors
keywords: Aneurysmal subarachnoid hemorrhage; autonomic shift; immunosuppression; infection