Comparison of the Canadian CT Head Rule and the New Orleans Criteria in Patients With Minor Head Injury

TLDR

CT use for minor head injury is rapidly expanding but highly variable, prompting the development of the Canadian CT Head Rule and New Orleans Criteria to guide imaging decisions. This study aims to compare the clinical performance of the CCHR and NOC in detecting neurosurgical intervention and clinically important brain injury. In a prospective cohort of 2,707 adults with blunt head trauma (GCS 13–15) across nine Canadian EDs, 1,822 patients with GCS 15 were evaluated using both rules, with outcomes assessed by CT and follow‑up interviews. Both rules achieved 100 % sensitivity, but the CCHR was markedly more specific (76.3 % vs 12.1 % for neurosurgery; 50.6 % vs 12.7 % for brain injury) and would reduce CT rates to 52.1 % versus 88.0 % for the NOC.

Abstract

ContextCurrent use of cranial computed tomography (CT) for minor head injury is increasing rapidly, highly variable, and inefficient. The Canadian CT Head Rule (CCHR) and New Orleans Criteria (NOC) are previously developed clinical decision rules to guide CT use for patients with minor head injury and with Glasgow Coma Scale (GCS) scores of 13 to 15 for the CCHR and a score of 15 for the NOC. However, uncertainty about the clinical performance of these rules exists.ObjectiveTo compare the clinical performance of these 2 decision rules for detecting the need for neurosurgical intervention and clinically important brain injury.Design, Setting, and PatientsIn a prospective cohort study (June 2000-December 2002) that included 9 emergency departments in large Canadian community and university hospitals, the CCHR was evaluated in a convenience sample of 2707 adults who presented to the emergency department with blunt head trauma resulting in witnessed loss of consciousness, disorientation, or definite amnesia and a GCS score of 13 to 15. The CCHR and NOC were compared in a subgroup of 1822 adults with minor head injury and GCS score of 15.Main Outcome MeasuresNeurosurgical intervention and clinically important brain injury evaluated by CT and a structured follow-up telephone interview.ResultsAmong 1822 patients with GCS score of 15, 8 (0.4%) required neurosurgical intervention and 97 (5.3%) had clinically important brain injury. The NOC and the CCHR both had 100% sensitivity but the CCHR was more specific (76.3% vs 12.1%, P<.001) for predicting need for neurosurgical intervention. For clinically important brain injury, the CCHR and the NOC had similar sensitivity (100% vs 100%; 95% confidence interval [CI], 96%-100%) but the CCHR was more specific (50.6% vs 12.7%, P<.001), and would result in lower CT rates (52.1% vs 88.0%, P<.001). The κ values for physician interpretation of the rules, CCHR vs NOC, were 0.85 vs 0.47. Physicians misinterpreted the rules as not requiring imaging for 4.0% of patients according to CCHR and 5.5% according to NOC (P = .04). Among all 2707 patients with a GCS score of 13 to 15, the CCHR had sensitivities of 100% (95% CI, 91%-100%) for 41 patients requiring neurosurgical intervention and 100% (95% CI, 98%-100%) for 231 patients with clinically important brain injury.ConclusionFor patients with minor head injury and GCS score of 15, the CCHR and the NOC have equivalent high sensitivities for need for neurosurgical intervention and clinically important brain injury, but the CCHR has higher specificity for important clinical outcomes than does the NOC, and its use may result in reduced imaging rates.