An MRI Study of Post-operative Delirium in Patients Undergoing Major Surgery

Summary

Participation Requirements

Description

Methods: Informed witnessed consent will be obtained from all participants. Patients will have a Mini Mental State Exam (MMSE) prior to their MRI studies. A battery of neurocognitive tests will be undertaken for each subject prior to surgery. This test battery will include PHQ-9, GAD-7, Trails A and...

Methods: Informed witnessed consent will be obtained from all participants. Patients will have a Mini Mental State Exam (MMSE) prior to their MRI studies. A battery of neurocognitive tests will be undertaken for each subject prior to surgery. This test battery will include PHQ-9, GAD-7, Trails A and WAIS-IV Digit Span, Hopkins Verbal Learning Test Revised, Rey's Complex Figure, DKEFS, F-A-S, CLOX I and II. This will take 45-60 minutes. Patients will have CVR maps with blood oxygen level dependent (BOLD-MRI) pulse sequences done with standard RespirAct (a computer-controlled gas blender) protocols in association with anatomic imaging in a 3.0 Tesla magnet. The clinical care team and patient will be blinded as to the CVR results. Patients will have standardized anesthesia and per usual approaches for their major surgery and have standard POD assessment tools (CAM-ICU and CAM-S). Storage of anesthesia hemodynamics will be to digital data acquisition systems for later collation. End-tidal CO2 will be targeted at patient baseline values +/- 2.5 mmHg during the surgical procedure and if ventilated for any period post-operatively. Inspired O2 will be targeted to 0.3 - 0.6, based on pulse oximetry of greater than 95% with adequate arterial oxygenation confirmed by ABG. Standard fast-track protocols and admission to the surgical special care unit (SSCU) will be undertaken to facilitate patient management. Any patient with obvious POD, post-op delirium or stroke will be managed per usual protocols. Multiple CVR maps (650 studies) have been done at University Health Network in Toronto. As well over 150 studies have been conducted at the Health Sciences Centre at the University of Manitoba in the past 5 years. Significance/Importance: This study has the potential to make an important contribution in the understanding of POD for all surgical procedures and specifically a window into the problem with major surgery. A positive study based on our hypothesis can fundamentally change our understanding of cognitive dysfunction after surgery. Large follow-up multicentre trials can be constructed based on initial findings from this pilot study if the study bears fruit. At the least, further elucidation into POD for major surgery is expected with this study. tighter control of end-tidal gases may be a consequence of the findings of this study.

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