الفهرس 
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Abstract
Lactic acidosis is not a disease but a phenomenon that
occurs in association with a number of serious disorders,
which cause considerable morbidity and mortality. The
production of lactic acid is not pathological. Rather, it is a vital
source of necessary ATP both at its site of production and for
distant tissues (Hood, 2005).
Disorders of acid-base balance can be found in as many
as nine of every ten patients in the ICU, which means that
acid-base disorders may be the most common clinical
problems you will encounter in the ICU. Aberrant lactate
metabolism is frequently encountered among critically ill
patients. The overall incidence of lactic acidosis in critically ill
patients is unknown; however, increasing acid-base
evaluations of critically ill patients indicate its persistence
increases associated morbidity and mortality (Marino, 2007).
Lactic acidosis is probably the most common cause of
severe metabolic acidosis encountered in the intensive care
unit. The AG is always increased above baseline (normal
lactate level is below 1.0 mmol per L), because lactate does
not appear in the urine until a higher plasma concentration is
achieved, the tubular threshold being 6 to 8 mmol per L.
Lactate levels greater than 5 mmol per L are considered
diagnostic of lactic acidosis, although levels between 2 and 5
mmol per L may be significant in the appropriate clinical
circumstances (Robert and Gary, 2008).
Metformin, a biguanide commonly used in the treatment
of type II diabetes mellitus, can cause of lactic acidosis,
particularly in patients who have presented typically with
acute or chronic renal insufficiency. Hemodialysis has been
used in the treatment for metformin-induced acidosis. This
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medication is generally discouraged in patients with chronic
renal insufficiency (Nyirenda et al., 2006).
In clinical practice, separation of types A and B lactic
acidosis is usually not helpful, because many critically ill
patients have combined abnormalities. Increased lactate
formation from tissue hypoxia and decreased lactate clearance
often occur together (Cooper and Alistair, 2009).
Because thiamine deficiency may be common in
critically ill patients, this diagnosis should be considered in all
cases of unexplained hyperlactatemia in the ICU (Marino,
2007).
It is important to remember that, in healthy athletes,
severe lactic acidosis during exercise is a normal, self-limited
observation (Rivers et al., 2001) .