Severe Hypothermia Increases the Risk for Intensive Care Unit-acquired Infection

Background: Although hypothermia is widely accepted as a risk factor for subsequent infection in surgical patients, it has not been well defined in medical patients. We sought to assess the risk of acquiring intensive care unit (ICU)--acquired infection after hypothermia among medical ICU patients.

Methods: Adults (≥18 years) admitted to French ICUs for at least 2 days between April 2000 and November 2010 were included. Surgical patients were excluded. Patient were classified as having had mild hypothermia (35.0°C-35.9°C), moderate hypothermia (32°C-34.9°C), or severe hypothermia (<32°C), and were followed for the development of pneumonia or bloodstream infection until ICU discharge.

Results: A total of 6237 patients were included. Within the first day of admission, 648 (10%) patients had mild hypothermia, 288 (5%) patients had moderate hypothermia, and 45 (1%) patients had severe hypothermia. Among the 5256 patients who did not have any hypothermia at day 1, subsequent hypothermia developed in 868 (17%), of which 673 (13%), 176 (3%), and 19 (<1%) patients had lowest temperatures of 35.0°C-35.9°C, 32.0°C-34.9°C, and <32°C, respectively. During the course of ICU admission, 320 (5%) patients developed ICU-acquired bloodstream infection and 724 (12%) patients developed ICU-acquired pneumonia. After controlling for confounding variables in multivariable analyses, severe hypothermia was found to increase the risk for subsequent ICU-acquired infection, particularly in patients who did not present with severe sepsis or septic shock.

Conclusions: The presence of severe hypothermia is a risk factor for development of ICU-acquired infection in medical patients.