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.

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.

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 Pao ₂/Fio ₂ of 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.

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.