Munich cCT Rule for Patients with Recreational Drug and Ethanol Poisoning

<b>Background:</b> Patients with recreational drug and ethanol poisoning often present with reduced consciousness, coma, or disorientation. It is often unclear if there was recent head trauma. Algorithms to perform cranial computed tomography (cCT) like the Canadian CT Head Rule (CCHR), the National Emergency X-Radiography Utilization Study Head CT Decision Instrument (NEXUS DI), or the New Orleans Criteria (NOC) exist for patients with head trauma. It is unclear whether these algorithms can be applied to this patient collective. <b>Methods:</b> This is a retrospective data analysis of patients admitted to our emergency department with drug or ethanol poisoning in 2019. Minors < 16 years were excluded. The primary outcome was fracture/bleeding in cCT, the secondary outcome was neurosurgical intervention. These results were calculated: 1. Sensitivity and negative predictive value (NPV) of the CCHR, NEXUS DI, and NOC. 2. Uni- and multivariate analysis of risk factors for critical findings. 3. The Munich cCT Rule sensitivity and NPV. <b>Results:</b> A total of 420 patients were included. cCT was performed in 120 patients. Eight patients had fracture/bleeding in cCT, two required neurosurgical intervention. The number of patients at risk, sensitivity, and NPV for critical cCT findings were as follows: CCHR 57/25%/98.3%, NEXUS DI 239/100%/100%, NOC 420/100%/100%. The sensitivity and NPV for neurosurgical intervention were as follows: CCHR 50%/99.7%, NEXUS DI 100%/100%, NOC 100%/100%. In univariate analysis, these findings correlated significantly with the following critical findings: accident, injury, injury above clavicle, head wound, anisocoria, ethanol in serum > 2 g/L, hypotension, drug ingestion, GCS < 8, focal neurological deficit, age > 60, and cerebellar symptoms. Via chi-square recursive partitioning analysis, we created the Munich cCT Rule which is positive for intoxicated patients if both an accident and an ethanol level > 2 g/L are present. This identified 70 patients at risk. It excluded fracture/bleeding and neurosurgical intervention with a sensitivity and NPV of 100%. <b>Conclusions:</b> Fracture/bleeding in cCT in intoxicated patients is rare. Performing unnecessary cCTs should be avoided. The Munich cCT Rule for patients with recreational drug and ethanol poisoning may help rule out critical findings and is superior to the NEXUS DI and NOC. It also has a 100% sensitivity which the CCHR (25%) is lacking.