Emergency department discharge of patients with a negative cranial computed tomography scan after minimal head injury

Objective To determine the negative predictive value of cranial computed to mography (CT) scanning in a prospective series of patients and whether hosp ital admission for observation is mandatory after a negative diagnostic eva luation after minimal head injury (MHI). Summary Background Data Hospital admission for observation is a current sta ndard of practice for patients who have sustained MHI, despite having under gone diagnostic studies that exclude the presence of an intracranial injury . The reasons for this practice are multifactorial and include the perceive d false-negative rate of all standard diagnostic tests, the belief that adm ission will allow prompt diagnosis of occult injuries, and medicolegal cons iderations about the risk of early discharge. Methods in a prospective, multiinstitutional study during a 22-month period at four level I trauma centers, all patients with MHI were evaluated using the following protocol: a standardized physical and neurologic examination in the emergency department, cranial CT scanning, and then admission for o bservation. MHI was defined as either a documented loss of consciousness or evidence of posttraumatic amnesia and an emergency department Glasgow Coma Scale score of 14 or 15. Outcomes were measured at 20 hours and at dischar ge and included clinical deterioration, need for craniotomy, and death. Results Two thousand one hundred fifty-two consecutive patients fulfilled t he study protocol. The CT was interpreted as negative for intracranial inju ry in 1,788, positive in 217, and equivocal in 119. Five patients with CT s cans initially interpreted as negative required intervention, There was one craniotomy in a patient whose CT scan was initially interpreted as negativ e. This patient had racial fractures that required surgical intervention an d elevation of depressed intracranial fracture fragments. The negative pred ictive power of a cranial CT scan based on the preliminary reading of the C T scan and defined by the subsequent need for neurosurgical intervention in the population fully satisfying the protocol was 99.70%. Conclusions Patients with a cranial CT scan, obtained on a helical CT scann er, that shows no intracerebral injury and who do not have other body syste m injuries or a persistence of any neurologic finding can be safely dischar ged from the emergency department without a period of either inpatient or o utpatient observation. Implementation of this practice could result in a po tential decrease of more than 500,000 hospital admissions annually.