A study found that errors involving leaving surgical sponges or instruments inside patients are more likely to happen during emergency procedures, or in operations where there is a sudden change in plan. Additionally the research revealed that the higher a patient’s weight, the more statistically likely it is that an object will be inadvertently left behind. “Often when you hear about these kinds of cases, people assume it is due to negligence,” said Atul Gawande of Brigham and Women’s Hospital. “But we found that these errors usually occur despite teams following proper procedures. These errors tend to occur in unpredictable situations, such as emergency operations, that challenge standard protocols.” Gawande and his colleagues analyzed malpractice claims filed with one particular insurance company between 1985 and 2001. In all, 54 cases were confirmed to involve retained objects. Sixty-nine percent of the cases involved sponges, and 31 percent involved instruments. These cases were then compared to data from patients undergoing the same operations who did not have this complication. In emergency operations, retained object errors are nine times more likely to happen, the study showed. The findings appeared in the January 16, 2003 edition of the New England Journal of Medicine.