title: Relationship between acid-base status and inflammation in the critically ill.
abstract: BACKGROUND
  There is a complex interplay between changes in acid-base components and inflammation. This manuscript aims to explore associations between plasma cytokines and chemokines and acid-base status on admission to intensive care.
  
  
  METHODS
  We conducted a prospective cohort study in a 13-bed ICU in a tertiary-care center in Brazil. 87 unselected patients admitted to the ICU during a 2-year period were included. We measured multiple inflammatory mediators in plasma using multiplex assays and evaluated the association between mediator concentrations and acid-base variables using a variety of statistical modeling approaches, including generalized linear models, multiadaptive regression splines and principal component analysis.
  
  
  RESULTS
  We found a positive association between strong ion gap (SIG) and plasma concentrations of interleukin (IL)6, 8, 10 and tumor necrosis factor (TNF); whereas albumin was negatively associated with IL6, IL7, IL8, IL10, TNF and interferon (IFN)α. Apparent strong ion difference (SIDa) was negatively associated with IL10 and IL17. A principal component analysis including SAPS 3 indicated that the association between acid-base components and inflammatory status was largely independent of illness severity, with both increased SIG and decreased SIDa (both drivers of acidosis) associated with increased inflammation.
  
  
  CONCLUSIONS
  Acid-base variables (especially increased SIG, decreased albumin and decreased SIDa) on admission to ICU are associated with immunological activation. These findings should encourage new research into the effects of acid-base status on inflammation.
authors.forename: Fernando G
authors.initials: FG
authors.lastname: Zampieri
authors.forename: John A
authors.initials: JA
authors.lastname: Kellum
authors.forename: Marcelo
authors.initials: M
authors.lastname: Park
authors.forename: Otavio T
authors.initials: OT
authors.lastname: Ranzani
authors.forename: Hermes V
authors.initials: HV
authors.lastname: Barbeiro
authors.forename: Heraldo P
authors.initials: HP
authors.lastname: de Souza
authors.forename: Luiz Monteiro
authors.initials: LM
authors.lastname: da Cruz Neto
authors.forename: Fabiano Pinheiro
authors.initials: FP
authors.lastname: da Silva
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000328:Adult; D015331:Cohort Studies; D016638:Critical Illness / Q000453:epidemiology; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D007362:Intensive Care Units / Q000639:trends; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D016207:Cytokines