title: Delayed neuropsychological sequelae after carbon monoxide poisoning: predictive risk factors in the Emergency Department. A retrospective study.
abstract: BACKGROUND
  Delayed neuropsychological sequelae (DNS) commonly occur after recovery from acute carbon monoxide (CO) poisoning. The preventive role and the indications for hyperbaric oxygen therapy in the acute setting are still controversial. Early identification of patients at risk in the Emergency Department might permit an improvement in quality of care. We conducted a retrospective study to identify predictive risk factors for DNS development in the Emergency Department.
  
  
  METHODS
  We retrospectively considered all CO-poisoned patients admitted to the Emergency Department of Careggi University General Hospital (Florence, Italy) from 1992 to 2007. Patients were invited to participate in three follow-up visits at one, six and twelve months from hospital discharge. Clinical and biohumoral data were collected; univariate and multivariate analysis were performed to identify predictive risk factors for DNS.
  
  
  RESULTS
  Three hundred forty seven patients were admitted to the Emergency Department for acute CO poisoning from 1992 to 2007; 141/347 patients participated in the follow-up visit at one month from hospital discharge. Thirty four/141 patients were diagnosed with DNS (24.1%). Five/34 patients previously diagnosed as having DNS presented to the follow-up visit at six months, reporting a complete recovery. The following variables (collected before or upon Emergency Department admission) were associated to DNS development at one month from hospital discharge in the univariate analysis: CO exposure duration >6 hours, a Glasgow Coma Scale (GCS) score <9, seizures, systolic blood pressure <90 mmHg, elevated creatine phosphokinase concentration and leukocytosis. There was no significant correlation with age, sex, voluntary exposure, headache, transient loss of consciousness, GCS between 14 and 9, arterial lactate and carboxyhemoglobin concentration. The multivariate analysis confirmed as independent prognostic factors GCS <9 (OR 7.15; CI 95%: 1.04-48.8) and leukocytosis (OR 3.31; CI 95%: 1.02-10.71).
  
  
  CONCLUSIONS
  Our study identified several potential predictive risk factors for DNS. Treatment algorithms based on an appropriate risk-stratification of patients in the Emergency Department might reduce DNS incidence; however, more studies are needed. Adequate follow-up after hospital discharge, aimed at correct recognition of DNS, is also important.
authors.affiliation: Emergency Department, Careggi University General Hospital, Via delle Oblate 1, 50139 Florence, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pepe
authors.forename: Matteo
authors.initials: M
authors.lastname: Castelli
authors.forename: Peiman
authors.initials: P
authors.lastname: Nazerian
authors.forename: Simone
authors.initials: S
authors.lastname: Vanni
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Panta
authors.forename: Francesco
authors.initials: F
authors.lastname: Gambassi
authors.forename: Primo
authors.initials: P
authors.lastname: Botti
authors.forename: Andrea
authors.initials: A
authors.lastname: Missanelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Grifoni
mesh_terms: D000328:Adult; D002249:Carbon Monoxide Poisoning / Q000503:physiopathology* / Q000628:therapy; D018450:Disease Progression; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D006931:Hyperbaric Oxygenation; D007558:Italy; D008297:Male; D001523:Mental Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D009422:Nervous System Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D009483:Neuropsychological Tests; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods