الفهرس 
Pathophysiology & Epidemiology of DeliriumOnly 14 pages are availabe for public view
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Abstract
D
elirium is defined as a change in mental status, characterized by acute onset and fluctuating course, inattention, disorganized thinking, and altered level of consciousness. Symptoms manifest as hyperactive (e.g., restless, agitated, emotional liability), hypoactive (e.g., somnolence, withdrawal from the environment) or mixed delirium. Delirium is recognized as an adverse consequence of critical illness. During intensive care unit (ICU) stay, complications such as the self-extubation exit of life-saving catheters and asynchrony between patient and ventilator, sternum instability, and the need for surgical revision of the sternal wound may increase. The reported incidence of delirium in the elderly after cardiac surgery ranged from (11%–46%) was explained by the different study designs and different methods of assessing delirium
The exact pathophysiology and etiology of delirium are unknown and the onset of delirium in each patient is caused by an interaction of predisposing and precipitating factors.
Different scales have been published that allow the non-psychiatrically trained ICU staff to diagnose delirium. The Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) are the most reliable and valid screening tools for the adult critically ill patients. The CAM-ICU is a standardized approach for the assessment of delirium in the intensive care unit.
Among ICU patients who develop delirium and who require continuous sedation therapy, the Pain, Anxiety and Delirium guidelines recommend that either propofol or dexmedetomidine should be considered as a replacement for benzodiazepine therapy.
Dexmedetomidine is a highly selective and potent central alpha 2-receptor agonist that binds to transmembrane G protein-binding adrenoreceptors and has no activity on the g-aminobutyric acid system. Dexmedetomidine has opioid-sparing effects by decreasing central nervous system sympathetic outflow. Dexmedetomidine is unique among sedatives used in the ICU because it produces sedation and analgesia without causing respiratory depression.
Propofol is a rapid-acting hypnotic and sedative agent with no analgesic properties that increase the binding affinity of GABA. Its mechanisms of action are through potentiation of the central inhibitory neurotransmitter γ-aminobutyric acid receptor activity and also through sodium channel blockade. Propofol provides myocardial protection in the cardiac surgery patient
The study was done on 150 patients to compare dexmedetomidine versus propofol in reducing delirium post-cardiac surgery in elderly patients. They were divided into 2 equal groups; 75 patients received dexmedetomidine in a dose ranging from 0.2 μg/kg/hr up to max 0.7μg/kg/hr immediately post-operative, the other group; 75 Patients in the propofol group receiving propofol infusion in ICU from 25 to max 50 μg/kg/ min. until readiness for tracheal extubation. If mechanical ventilation would be required beyond the 24 h period, based on the institutional standard of practice, patients in the dexmedetomidine group would be converted to propofol sedation
The study measured the incidence, onset, and duration of delirium, duration of mechanical ventilation, doses of analgesics requirement, ICU and hospital length of stay in both groups
The study revealed that dexmedetomidine reduced the Incidence, onset, and duration of delirium, duration of mechanical ventilation, but no difference in length of stay in ICU and hospital length of stay between both groups.