الفهرس 
: Pathophysiological considerations forOnly 14 pages are availabe for public view
 |  | from | 82 |  |  |
| | | from | 82 | | |
Abstract
Over the last decade, ICU-related neurocognitive impairment has been identified as a significant public health problem and has become the focus of intense investigation by researchers around the world. Potential neurologic consequences of critical illness include delirium and long-term cognitive impairments. The extent of their association in intensive care unit is very high due to the high prevalence of delirium and persistent cognitive impairments in critically ill patients.
Delirium is a neurobehavioral syndrome characterized by acute confusion, inattention, disorganized thinking, and fluctuating mental status changes. Delirium may be the most common neuropsychiatric condition experienced by hospitalized elderly.
There are multiple physiological and pharmacologic factors that affect the central nervous system resulting in delirium and long-term cognitive impairments. A variety of theories have been proposed to explain the suspected mechanisms of delirium. Delirium is thought to be multifactorial and its pathogenesis is likely due to interactions between patient vulnerability and precipitating factors including critical illness.
Numerous risk factors for its development. Patients who are highly vulnerable to delirium may experience the disorder after only minor physiologic stressors, whereas those with low baseline vulnerability require a more noxious insult to become delirious. Three or more risk factors increase the likelihood for the development of delirium. The risk factors can be divided into tow main categories:
(1) Predisposing factors (e.g, old age, chronic illness) and (2) precipitating factors (e.g, hypoxia, hypoglycemia, metabolic impairment and sedatives).
Development of delirium during the initial ICU admission is one of the strongest predictors of prolonged cognitive impairment and mortality. Hence diagnosis, management, and interventions aimed at reducing the acute neurocognitive effects of critical illness are of great importance. The development of delirium often goes unnoticed in the ICU because we think of it as ‘part of the scenery’ or an expected and inconsequential outcome of mechanical ventilation and other therapies necessary to save lives in the ICU.
A series of investigations have been conducted that provided validated means of detecting delirium by non-psychiatrists (e.g., nurses, or respiratory therapists) like (ICDSC) and (CAM-ICU).We propose implementation of a bundle of processes, awakening and breathing coordination, delirium monitoring, and exercise/ early mobility or the (ABCDE) bundle, to aid in management of delirium.
The most effective strategy to reduce delirium and its associated complica¬tions is primary prevention before delirium occurs. Preventive strategies should address important risk factors and target moderate- to high-risk patients at baseline. Preventive efforts require system-wide changes to educate physicians and nurses, improve their recognition of delirium, and heighten their awareness of its clinical implications. It is also of importance to provide incentives to change practice patterns that lead to delirium (e.g., immobiliza¬tion, sleep medications and physical restraints) and to create systems that enhance high-quality geriatric care Medications
Medications should be used only after adequate attention has been given to the correction of modifiable contributing factors, such as sleep disturbance and restraints. It is important to recognize that delirium could be a manifestation of an acute, life-threatening problem that requires immediate attention, such as hypoxia, hypercarbia, hypoglycemia, metabolic derangements, or shock. After such concerns have been addressed, delirious patients should be considered for pharmacologic management .It should be recognized that although agents used to treat delirium are intended to improve cognition, they all have psychoactive effects that may further cloud the sensorium and promote a longer overall duration of cognitive impairment. Therefore, these drugs should be used judiciously in the smallest possible dose and for the shortest time necessary.