title: The Frequency of White Blood Cell and Temperature Events During Mechanical Ventilation and Their Association With Ventilator-Associated Events.
abstract: BACKGROUND
  Changes in white blood cell (WBC) counts and/or temperature could have important implications in patients on ventilators, but the frequency of these events is uncertain.
  
  
  METHODS
  We reviewed the medical records from 281 ventilation episodes in our medical intensive care unit to determine patient characteristics and the indications for ventilation. We determined the number of days during each ventilation episode in which the temperature (<96.8°F, >100.4°F) or WBC count (<4000/µL, >12 000/µL) was out of the normal range.
  
  
  RESULTS
  This study included 257 patients with a mean Acute Physiology and Chronic Health Evaluation 2 score of 13.5 ± 5.9 and a mean initial Pao2/Fio2of 210 ± 110. The median number of ventilator days was 4 (interquartile range, 3-9). One hundred ninety-six of 275 eligible ventilator episodes (71.3%) had 1 or more temperature events, and 194 of 253 eligible ventilator episodes (76.7%) had 1 or more WBC events. Nineteen patients met the Center for Disease Control criteria for a ventilator-associated event (VAE). Twelve patients had an increased WBC count during the VAE period, and 11 had an increased temperature during this period.
  
  
  CONCLUSIONS
  White blood cell counts and temperature events occur frequently in patients on ventilators and need evaluation but do not reliably identify patients with ventilator-associated complications.
authors.affiliation: 1 Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Hawa
authors.initials: H
authors.lastname: Edriss
authors.affiliation: 1 Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Whiting
authors.affiliation: 1 Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nugent
mesh_terms: D000368:Aged; D001831:Body Temperature / Q000276:immunology*; D003422:Critical Care; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000401:mortality / Q000517:prevention & control; D011237:Predictive Value of Tests; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000401:mortality; D012189:Retrospective Studies; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology
keywords: fever; mechanical ventilation; pneumonia; ventilator-associated events; white blood cells