Glass thermometer injuries: it is not just about the mercury

Glass mercury thermometers were once used as the criterion standard for measuring core body temperature. Once broken, however, there is the dual hazard of broken glass and exposure to mercury. Previous studies have focused only on the mercury hazard rather than injuries related to thermometer glass.

To identify injury patterns from glass thermometers, including glass-related injury and mercury exposure.

We performed a retrospective cohort study of glass thermometer-related injuries in children evaluated in a pediatric emergency department between October 1995 and October 2007. Case identification was performed using a computer-assisted screening tool followed by a manual chart review. Collected data included age, sex, injury characteristics, physical examination findings, radiologic imaging, interventions, and disposition. To analyze injury rates during these years, we used a multiplicative Poisson model allowing for varying exposures.

Thirty-three patients were identified among 627,592 who presented to the emergency department during the study period. Approximately 1 to 6 patients presented every year, including 3 patients in 2007. Decline in injury incidence is less than 9% per year (P = 0.041). Median patient age was 2.4 years (interquartile range, 0.4-3.8 years); 12 patients (36%) were female. Twenty-two patients (66%) underwent radiologic imaging to identify potential foreign body (21 underwent radiography and 1 underwent computed tomographic scanning). There were 15 mouth injuries (45%), 13 anal injuries (39%), and 1 ear injury. Glass was identified by imaging in 5 patients (15%) and by sigmoidoscopic evaluation in 1 patient (3%). Mercury exposure was identified in 14 patients (42%).

Persistent use of glass mercury thermometers has resulted in pediatric injury especially in children younger than 4 years. We reported the different mechanisms of injury with the hope of eliminating its use and reinforcing the use of alternative thermometers.