Presurgical Thalamus Volume in Postoperative Delirium: A Longitudinal Observational Cohort Study in Older Patients.

BACKGROUND: Previous studies suggest a role of the thalamus in cognitive function, while others implicate it as a central effect site of anesthetics. Yet, its role in postoperative neurocognition in the aging brain remains uncertain. We used presurgical thalamic volume as a functional indicator and determined its association with postoperative delirium (POD). METHODS: For this study, 301 older adults (aged ≥65) without dementia and scheduled for surgery were enrolled. Before surgery, participants underwent magnetic resonance imaging (MRI). Thalamus volume was segmented using Freesurfer (Version 5.3.). Participants were screened for POD twice a day until discharge or for a maximum of 7 days. POD was defined as a positive screening on ≥1 of 4 validated instruments: Richmond Agitation Sedation Scale (RASS), Nursing Delirium Screening Scale (Nu-DESC), Confusion Assessment Method (CAM), and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) score. A logistic regression associated thalamus volume with POD with adjustment for age, global brain atrophy, and physical status according to the American Society of Anesthesiologists (ASA) classification. RESULTS: In this cohort, 44 participants (14.6%) were diagnosed with POD. Independently of age, global brain atrophy, and physical status score, a higher preoperative thalamus volume was associated with a reduced odds of POD (odds ratio per 1-cm3 increment; 0.73 [95% confidence interval (CI), 0.58-0.92]; P = .008). CONCLUSIONS: A larger thalamus volume was associated with reduced odds of POD. Thus, the thalamus marks a region of interest in POD in the aging brain. These findings may help to understand the neuronal basis of POD.

Perioperative Management of Alcohol Withdrawal Syndrome.

BACKGROUND: In the perioperative course, alcohol withdrawal syndrome (AWS) can occur in any setting, especially in aero-digestive and acute trauma surgery. Challenging issues are the overlap of other forms of delirium in perioperative and intensive care settings as well as general anesthesia masking the onset of withdrawal symptoms. In contrast to other etiologies of delirium, the pathophysiology and thus treatment strategy of AWS is different: the key point is the tolerance to GABAergic molecules of alcohol-dependent subjects resulting in central nervous hyperactivity once the effect of alcohol or other GABA-stimulating agents is decreased. SUMMARY: Despite limitations due to insufficient accuracy of self-reporting questionnaires and limited feasibility in emergency settings, the AUDIT and the shortened AUDIT-C are the standard tools for detection of alcohol use disorders (AUD), as well as predicting AWS risk and severity in approximately half of these AUD patients. The most important risk factors for AWS are a high blood alcohol concentration at hospital admission, AWS episodes in medical history, and lack of control of alcohol use. Patients considered at risk for severe AWS must be treated with prophylactic medication before the onset of symptoms. Thiamine supplementation is required for all malnourished alcohol-dependent patients. Writing down alcohol-related diagnoses in the medical records requires the patient's presumed consent after shared decision-making. These reports should remain strictly confidential if the patient desires. Psychological support for the perioperative period as well as the following course should be offered to all AUD patients including support in short- and long-term detoxification. Alternative diagnoses must be ruled out with no timely delay, especially if fever and coma are the leading symptoms. The backbone of AWS therapy is the symptom-triggered administration of intravenous benzodiazepines (BZO) in escalating doses until the aimed revised Clinical Institute Withdrawal Assessment for Alcohol Scale (CIWA-Ar) or Richmond Agitation-Sedation Scale (RASS) score is achieved. Clonidine, dexmedetomidine, baclofen, ketamine, and neuroleptics may be used as symptom-orientated adjuncts. The therapeutic administration of ethanol or clomethiazole is considered to be harmful in critically ill patients after the onset of AWS. General supportive and intensive care including high-dose thiamine supplementation are mandatory in severe AWS cases. The timely differential diagnosis of delirium is important - and AWS is a diagnosis of exclusion - because BZO are strongly recommended for AWS patients but may not be the treatment of choice in other etiologies of delirium. KEY MESSAGES: Screening for AWS risk factors should be integrated in the preoperative and emergency assessment. Other severe diagnoses must be ruled out before the diagnosis of AWS can be established. Preventive treatment should be given to high-risk patients scoring positive for AUD and for patients with a lack of alcohol use control. The principles of AWS therapy are symptom-orientated doses of BZO and as adjuncts α2-agonists, neuroleptics, and others guided by repeated reassessment with validated tools and thiamine administration. Length of stay and morbidity are reduced if AWS therapy is symptom-orientated and protocol-based.