Monitoring bladder temperatures in the OR

Temperature monitoring via the urinary bladder has become common in the OR, often replacing monitoring at the rectal site. A systematic, integrated review and synthesis of the literature was undertaken to assess the validity of using the urinary bladder as a site for temperature measurement in the OR. During steady thermal states, bladder temperature performed well, providing temperatures similar to those of core sites. In contrast, poor performance was demonstrated during rapid thermal changes, such as during the rapid cooling and rewarming phases of cardiopulmonary bypass. At such times, a significant lag in response rate at the bladder site was noted by multiple investigators. This delayed responsiveness during thermally dynamic states, however, may provide information regarding the adequacy of rewarming during bypass at sites intermediate between the core and periphery. Limited research indicates that urinary bladder temperature may be influenced by urine flow rate, and additional research is required in this area. The cost effectiveness of this method of temperature measurement requires investigation as well.