title: Initial blood lactate correlates with carboxyhemoglobin and clinical severity in carbon monoxide poisoned patients.
abstract: OBJECTIVE
  The aim of this study was to assess the role of blood lactate levels at admission in carbon monoxide (CO)-poisoned patients for establishing severity of poisoning and short term prognosis.
  
  
  METHODS
  All cases of CO poisoning visited in the emergency department during the years 2012 and 2013 were retrieved from the hospital database. The concentration of COHb and lactate was assessed in arterial blood in all patients with suspected CO poisoning, along with the plasma concentration of troponin I (TnI). The control population for TnI results consisted in 125 blood donors.
  
  
  RESULTS
  Twenty three (61%) out of 38 CO-poisoned patients underwent hyperbaric oxygen (HBO) treatment, and 10 (26%) were admitted to a hospital ward. A significant correlation was found between lactate and COHb (r=0.54; p<0.001), and between lactate and TnI (r=0.44; p=0.001). A significant correlation was also found between COHb and TnI (r=0.38; p=0.020). Blood lactate levels were higher in patients treated with HBO and hospital admission. In multivariate analysis, none of the parameters was associated with HBO treatment, whereas increased value of blood lactate (p=0.036) was the only significant predictor of hospital admission. Twenty five (66%) patients had detectable TnI levels compared to 13% controls (p<0.001), whereas 16% CO-poisoned patients had TnI levels >99th percentile compared to 2% controls (p=0.003). The odds ratio for detectable TnI and TnI >99th percentile in CO-poisoned patients were 13.1 (p<0.001) and 7.6 (p=0.006), respectively.
  
  
  CONCLUSIONS
  Initial blood lactate level may be useful for risk stratification of CO-poisoned patients, especially for predicting hospitalization.
authors.affiliation: Emergency Department, Academic Hospital of Parma, Italy. Electronic address: gcervellin@ao.pr.it.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Cervellin
authors.affiliation: Emergency Department, Academic Hospital of Parma, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: Comelli
authors.affiliation: Emergency Department, Hospital of Vaio, Fidenza, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Rastelli
authors.affiliation: Laboratory of Clinical Chemistry and Haematology, Academic Hospital of Parma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Picanza
authors.affiliation: Laboratory of Clinical Chemistry and Haematology, Academic Hospital of Parma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D002249:Carbon Monoxide Poisoning / Q000097:blood* / Q000473:pathology / Q000628:therapy; D002263:Carboxyhemoglobin / Q000378:metabolism*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000706:statistics & numerical data; D007773:Lactates / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012720:Severity of Illness Index; D019210:Troponin I / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007773:Lactates; D019210:Troponin I; D002263:Carboxyhemoglobin
keywords: Carbon monoxide; Carboxyhemoglobin; Hyperbaric therapy; Lactate; Poisoning; Troponin