Critical Care: ICU Management and Outcomes |

Scanning the Confusion Away: The Diagnostic Utility of Head Computer Tomography (CT) in the Evaluation of Altered Mental Status in a Non-Neurological Medical ICU of a Tertiary Care Center FREE TO VIEW

Atul Mehta, MD; Ghaleb Khirfan, MD; Porus Shah, MD; Samuel Wiles, MD; Ajit Moghekar, MD; Shraddha Narechania; Abhijit Duggal, MD; Anil Vijayan, MD; Fatima Adhi, MD; Sudhir Krishnan, MD
Author and Funding Information

Cleveland Clinic Foundation, Cleveland, OH

Copyright 2016, American College of Chest Physicians. All Rights Reserved.

Chest. 2016;150(4_S):289A. doi:10.1016/j.chest.2016.08.302
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SESSION TITLE: ICU Management and Outcomes

SESSION TYPE: Original Investigation Slide

PRESENTED ON: Tuesday, October 25, 2016 at 08:45 AM - 10:00 AM

PURPOSE: Altered mental status (AMS) is a vague, non-descript albeit popular term often used to describe a perceived abnormality of arousal, cognition and/ or consciousness in the MICU. The spectrum of AMS could involve a myriad of clinicopathological conditions including but not limited to delirium, encephalopathy, post ictal states, toxic ingestions and intracranial catastrophes.Head CT is frequently obtained without careful clinical correlation and attention to the neurological examination . We sought to determine the diagnostic utility of Head CT in the diagnosis of AMS with and without a focal neurological deficit (FND)

METHODS: All consecutive CT heads requested, for evaluating the cause of AMS in adult patients admitted to the MICU for the year 2013 were identified retrospectively. A positive head CT was defined as a previously unrecognized intracranial process that could explain the AMS. Medical records were reviewed for a host of variables including but not limited to associated comorbidities, coagulopathies, risk factors for stroke arrhythmias, malignancies, immune status, sedation levels and need for mechanical for mechanical ventilation. Parametric and non parametric tests were employed as appropriate for continuous and categorical variables.

RESULTS: Sixty two percent (N=455) of the total head CTs( N=725)met the eligibility criteria( CT head requested for AMS). Eight percent of these head CT's(N=37) were positive for an acute intracranial process that could potential explain the AMS( for e.g-infarct) . Fifty two percent of the head CTs were reported with old chronic ischemic , white matter and/ or age related changes and 40% were reported as normal . Twenty three percent of the CT heads was reported as positive for an infarct, 29% for hemorrhage and 35% for cerebral edema. An association was identified between FND and head CT positivity. Of the 8% CT Head CTs that were positive25% (N=18) with an FND and 5 %(N=19) without a FND had a positive CT head [Odd ratio 6.7(CI-3.3 to 13.9) p< 0.0001)]. A multivariable logistic regression model failed to detect an association between CT head positivity and the other aforesaid variables (e.g-coagulopathies, risk factors for stroke arrhythmias, malignancies, immune status, sedation levels and need for mechanical for mechanical ventilation).

CONCLUSIONS: The diagnostic yield of head CT in determining the cause of AMS in a MICU may be low. Presence of a FND on clinical examination could identify a subset of patients who might be at higher risk and thus benefit from further elucidating the cause with a radiological investigation. Head CT may be unnecessary in a majority of the cases in the correct clinical context.

CLINICAL IMPLICATIONS: The low diagnostic utility of head CT in the clinical context of AMS leads to higher resource utilization, increased medical expenses and unnecessary radiation exposure. The intensivist may be frequently challenged with the daunting task of weighing the low diagnostic yield of CT head against the potential consequences of a missed acute intracranial process.

DISCLOSURE: The following authors have nothing to disclose: Atul Mehta, Ghaleb Khirfan, Porus Shah, Samuel Wiles, Ajit Moghekar, Shraddha Narechania, Abhijit Duggal, Anil Vijayan, Fatima Adhi, Sudhir Krishnan

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