title: Nurse workload and inexperienced medical staff members are associated with seasonal peaks in severe adverse events in the adult medical intensive care unit: A seven-year prospective study.
abstract: OBJECTIVE
  Our purpose was to identify potential organizational factors that contributed to life-threatening adverse events in adult intensive care unit.
  
  
  METHODS
  A prospective, observational, dynamic cohort study was carried out from January 2006 to December 2013 in a 20-bed adult medical intensive care unit. All patients admitted to the intensive care unit and who experienced one or more selected life-threatening adverse events (mainly unexpected cardiac arrest, unplanned extubation, reintubation after planned extubation, and readmission within 48h of intensive care unit discharge) were included in the analysis. Negative binomial regression was used to model how human resources, work organization, and intensive care activity influenced the monthly rate of selected severe adverse events. Data were collected from local and national databases.
  
  
  RESULTS
  Overall, 638 severe adverse events involving 498 patients were recorded. Adverse events increased seasonally in May, November and December (p<.001 vs other months). The proportion of inexperienced nurses and doctors' working hours could not explain these seasonal peaks of adverse events. Multivariate analysis identified bed-to-nurse ratio and the arrival of inexperienced residents or senior registrars as being independently associated with the rate of adverse events (incidence risk ratio=1.36 (95% confidence interval, 1.05-1.75), and 1.07 (95% confidence interval, 1.01-1.13), respectively; p=.01 in both cases). According to this model, a one-unit increase in the day-night shifts carried out by each nurse per month tended to reduce the rate of adverse events (incidence risk ratio=0.60 (95% confidence interval, 0.36-1.01), p=.05). Severity at intensive care unit admission did not influence the rate of adverse events (incidence risk ratio=1.02 (95% confidence interval, 1.00-1.04), p=.12).
  
  
  CONCLUSIONS
  Results identify nurse workload and the arrival of inexperienced residents or senior registrars as risk factors for the occurrence of life-threatening adverse events in the adult medical intensive care unit. Limiting fluctuations in bed-to-nurse ratio and providing inexperienced medical staff members with sufficient supervision may decrease severe adverse events in critically ill patients.
authors.affiliation: Service de Réanimation Médicale, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris, Université Paris Descartes, Sorbonne Paris Cité, Paris, France. Electronic address: christophe.faisy@egp.aphp.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Faisy
authors.affiliation: Service de Réanimation Médicale, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Cindy
authors.initials: C
authors.lastname: Davagnar
authors.affiliation: Institut National de la Statistique et des Etudes Economiques, Malakoff, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Ladiray
authors.affiliation: Santé Publique et Informatique Médicale, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, INSERM U729, and French Cochrane Network and Centre, Paris, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Djadi-Prat
authors.affiliation: Santé Publique et Informatique Médicale, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, INSERM U729, and French Cochrane Network and Centre, Paris, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Esvan
authors.affiliation: Santé Publique et Informatique Médicale, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, INSERM U729, and French Cochrane Network and Centre, Paris, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Lenain
authors.affiliation: Centre d'Investigations Epidémiologiques 4, INSERM, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Durieux
authors.affiliation: Santé Publique et Informatique Médicale, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, INSERM U729, and French Cochrane Network and Centre, Paris, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Leforestier
authors.affiliation: Service de Réanimation Médicale, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Marlet
authors.affiliation: Service de Réanimation Médicale, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Marta
authors.initials: M
authors.lastname: Seijo
authors.affiliation: Service de Réanimation Médicale, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Guillou
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009741:Nursing Staff, Hospital; D011446:Prospective Studies; D012621:Seasons; D016526:Workload
keywords: Adverse events; Crew resources management; Critical care; Duty hours/work hours; Medical errors; Nurse workload; Work organization