Preventable deaths due to errors in trauma patients with otherwise survivable injuries account for up to 10% of fatalities in Level I trauma centers, 50% of these errors occur in the intensive care unit (ICU). The root cause of 67% of the Joint Commission sentinel events is communication errors. The objective is (1) to study how critical information degrades and how it is lost over 24 hours and (2) to determine whether a structured checklist for ICU handoffs prevents information loss. Prospective cohort study of trauma and surgical ICU teams observed with and without use of the checklist. An observational period (control group) was followed by a didactic session on the science and use of a checklist (study group), which was used for patient management and handoffs. Information was tracked for a 24-hour period and all handoffs. Comparisons use chi or Fisher's exact test and a p value <0.05 was defined as significant. Three hundred and thirty-two patient ICU days were observed (119 control, 213 study) and 689 patient care items (303 control, 386 study) were followed. Seventy-five (10.9%) items were lost over 24 hours; 61 of 303 (20.1%) without checklist and 14 of 386 (3.6%) with checklist (p < 0.0001). Critical laboratory values and test results were the most frequent lost items (36.1% control vs. 4.5% study p < 0.0001). Six of 75 (8.1%) items were correctly ordered but not carried out by ICU nursing staff--all caught and corrected with checklist use. Critical information is degraded over 24 hours in the ICU. A structured checklist significantly reduces patient errors due to lost information and communication lapses between trauma ICU team members at handoffs of care.