الفهرس 
Pharmacology of micronutrientsOnly 14 pages are availabe for public view
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Abstract
icronutrients are nutrients required by humans and other organisms throughout life in
small quantities to orchestrate a range of physiological functions. For people, they include
dietary trace minerals in amounts generally less than
100 milligrams/day - as opposed to macrominerals which are required in larger quantities.
The microminerals or trace elements include iron, copper, manganese, selenium and zinc
Micronutrients also include vitamins, which are organic compounds required as
nutrients in tiny amounts by an organism.
Micronutrients deficiency usually occur in critically ill patients either due to increase demand,
decrease supply or increase losses.
Micronutrients deficiency can lead to increase length of stay in hospital, increase morbidity and
mortality.
Pathophysiology of critical illness is the net result of interaction of various mechanisms.
Oxidative stress, mitochondrial dysfunction and microcirculatory disturbance are the factors.
Oxidative stress is caused by Reactive Oxygen Species (ROS). Although ROS are constantly produced
under normal circumstances, critical illness can drastically increase their
production. These patients have reduced antioxidants and free electron scavengers or cofactors, and
decreased activity of the enzymatic system involved in ROS detoxification.
Biomarkers of oxidative stress can be used to monitor progression of the critical illness.
Biomarkers include markers of lipid peroxidation, markers of protein oxidation and cellular markers
of endothelial dysfunction.
Whenever artificial nutrition is required, micronutrients, i.e., vitamins and trace elements,
should be given from the first day of artificial nutritional support. Testing blood levels of
vitamins and trace elements in acutely ill patients is of very limited value as sensible clinical
judgment is usually sufficient.
Patients with major burns or major trauma and those with acute renal failure who are on continuous
renal replacement therapy or dialysis quickly develop acute deficits in some micronutrients, and
immediate supplementation is essential.
Other groups at risk of micronutrient deficiency are cancer patients, pregnant women with
hyperemesis and people with anorexia nervosa or other malnutrition or malabsorption states.
Clinicians need to treat minor deficits before they become clinical deficiencies .Delivery of
micronutrients in the early acute phase of recovery from critical illness must be continued and
high losses through excretion should be
minimized by infusing micronutrients slowly, over as long a
period as possible.
Individual patients may require additional supplements or smaller amounts of certain
micronutrients, depending on their clinical condition. Vitamin C and selenium should be
administered first in loading dose then maintenance dose to maximize their benefit esp. in septic
patients.
Various factors influence trace elements absorption. For example, copper absorption is enhanced
by ingestion of animal protein, citrate, and phosphate. Excess trace elements are as harmful
as their deficiency. For example: - excess manganese can cause Parkinson-like disease.
Vitamin C and Vitamin E act synergistically as antioxidants, so it is advised to supply them
simultaneously, also Vitamin D is gaining popularity in ICU nutrition system not only because its
role in respiratory epithelium integrity and decrease the incidence of pneumonia
Increase oxygen supply in septic shock patients don not necessarily improve their hypoxia as it is
usually at the mitochondrial level and it is also known as cytopathic hypoxia.