title: Patient to nurse ratio and risk of ventilator-associated pneumonia in critically ill patients.
abstract: OBJECTIVE
  To determine how the patient to nurse ratio affects risk for ventilator-associated pneumonia.
  
  
  METHODS
  Data from an earlier study in 27 intensive care units in 9 European countries were examined in a secondary analysis. The initial cohort included 2585 consecutive patients who had mechanical ventilation (1) after admission for treatment of pneumonia or (2) for more than 48 hours irrespective of the diagnosis at admission. In units with variable staffing levels, the highest patient to nurse ratio in a 24-hour period was considered. Patients from 6 units that did not provide data on nurse staffing levels were excluded from the analysis.
  
  
  RESULTS
  Ventilator-associated pneumonia developed in 393 of the 1658 patients (23.7%) in the secondary cohort. In units with patient to nurse ratios of 1 to 1, 2 to 1, 2.5 to 1, and 3 to 1, rates were 9.3%, 25.7%, 18.7%, and 24.2%, respectively (P = .003). Rates were significantly lower (P = .002) in units with a ratio of 1 to 1 (9.3%) than in units with a ratio of more than 1 patient to 1 nurse (24.4%). After adjustments for confounding covariates, ratios of more than 1 patient to 1 nurse were no longer associated with increased risk for ventilator-associated pneumonia.
  
  
  CONCLUSIONS
  A patient to nurse ratio of 1 to 1 appears to be associated with a lower risk for ventilator-associated pneumonia, but after adjustments for confounding covariates, the difference is not significant.
authors.affiliation: Ghent University Hospital, Ghent University, Belgium. stijn.blot@UGent.be
authors.forename: Stijn I
authors.initials: SI
authors.lastname: Blot
authors.forename: Mireia Llaurado
authors.initials: ML
authors.lastname: Serra
authors.forename: Despoina
authors.initials: D
authors.lastname: Koulenti
authors.forename: Thiago
authors.initials: T
authors.lastname: Lisboa
authors.forename: Maria
authors.initials: M
authors.lastname: Deja
authors.forename: Pavlos
authors.initials: P
authors.lastname: Myrianthefs
authors.forename: Emilpaolo
authors.initials: E
authors.lastname: Manno
authors.forename: Emili
authors.initials: E
authors.lastname: Diaz
authors.forename: Arzu
authors.initials: A
authors.lastname: Topeli
authors.forename: Ignacio
authors.initials: I
authors.lastname: Martin-Loeches
authors.forename: Jordi
authors.initials: J
authors.lastname: Rello
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016638:Critical Illness; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009741:Nursing Staff, Hospital / Q000600:supply & distribution*; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology / Q000209:etiology*; D012121:Respiration, Artificial / Q000009:adverse effects; D018570:Risk Assessment; D000078329:Workforce