Postoperative Delirium in Hip Arthroplasty Patients
Condition: Delirium; Postoperative Complications
MeSH terms: Delirium; Emergence Delirium; Postoperative Complications
Study type: Observational

Summary: 
      Identification of specific circulating microRNAs and microemboli formation (diagnosed by TC
      Doppler) in both delirious groups and nondelirious group will be our primary target. Delirium
      assessment through standardized questionnaires will be done at baseline (day of the surgery -
      pre operatory), immediately after surgery (in post anesthesia care unit) and then every 12
      hours in Day 1 and Day2 after surgery. The investigators will use linear mixed models to
      describe the change patterns overtime, and compare differences at each time point.
      Inflammatory biomarkers will be explored overtime as well. The investigators will also
      explore age effect on cognitive function - cognitive reserve - based on the score of the
      cognitive test administered at baseline.
    

Detailed description: 
      Specific circulating microRNA's have been identified in patients with neurological diseases
      or deficits, and specifically those with neurodegenerative conditions. Furthermore, available
      evidence primarily in pre-clinical / animal models supports the hypothesis that
      post-surgical/anesthesia - induced neuroinflammation leads to post-operative cognitive
      decline or dysfunction. The investigators hypothesize that specific circulating microRNA's
      involved in the pro-inflammatory response to surgery/anesthesia are a suitable biomarker of
      Delirium and/or POCD in surgical hip-arthroplasty patients. However, it is also possible that
      microamboli during the surgical procedure could contribute to these neurologic outcomes.
      Therefore, in addition to analyzing microRNA levels (our primary target), the investigators
      propose to monitor cerebral vascular flow during the surgery to possibly identify
      microambolic events using Transcranial Doppler. Overall, our overarching goal is to identify
      novel early clinical indicators of cognitive dysfunction (e.g. Delirium and POCD).

      The study will include preoperative-postoperative trajectory as well as the value of using
      subjects as self-controls with appropriate longitudinal analyses of cognition.

      There are many factors that are potential confounders in relation to cognitive decline and
      incident dementia.

      There are key characteristics and events:

        -  illnesses requiring hospitalization, that could potentially accelerate cognitive decline
           or worsen clinical dementia rating

        -  which anesthetic agents are administered for the surgical procedure

        -  intra-operative adverse events (anesthesia/surgery related, cerebral hypoxia,
           hypotension/hypertension, blood loss)

        -  patient factors (age, education, comorbidity)

        -  physiologic factors (inflammation,micro-embolization, blood-brain barrier function);

        -  perioperative factors (medications, sleep, complications)

        -  postoperative factors (rehabilitation, depression, social support)
    

Intervention name(s): miRNA Testing, Microemboli Monitoring, Delirium Assessment
Intervention type(s): Other
Intervention description(s): Delirium assessment questionnaire and blood testing for miRNA will be done for all patients postoperatively, as well as BIS monitoring during surgery. The three arms of the study indicate the allocation of each patient based on their delirium presentation (hypoactive, hyperactive, or none).
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Subjects schedule to undergo hip arthroplasty surgery