minimal alveolar concentration


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concentration

 [kon″sen-tra´shun]
1. increase in strength by evaporation.
2. the ratio of the mass or volume of a solute to the mass or volume of the solution or solvent.
3. intense mental focus.
hydrogen ion concentration see hydrogen ion concentration.
mass concentration the mass of a constituent substance divided by the volume of the mixture, as milligrams per liter (mg/l).
mean corpuscular hemoglobin concentration (MCHC) the average hemoglobin concentration in erythrocytes, conventionally expressed in “per cent,” meaning grams per deciliter of red blood cells, obtained by dividing the blood hemoglobin concentration (in g/dl) by the hematocrit (in l/l): MCHC = Hb/Hct.
minimal alveolar concentration (MAC) the concentration of anesthetic that at a pressure of 1 atmosphere produces immobility in 50 per cent of subjects exposed to a noxious stimulus.
minimal bactericidal concentration (MBC) the lowest concentration of a given antibiotic required to kill a specific organism.
minimal inhibitory concentration (MIC) the lowest concentration of a given antibiotic that inhibits the growth of a specific organism.
molar concentration the concentration of a substance expressed in terms of molarity.
concentration test a test of renal function based on the patient's ability to concentrate urine; see also fishberg concentration test.

min·i·mal al·ve·o·lar con·cen·tra·tion

the end-alveolar concentration of an inhalation anesthetic that prevents somatic response to a painful stimulus in 50% of patients; an index of relative potency of inhalation anesthetics.

median alveolar concentration

The end-tidal concentration (in standardised pressure units) of inhaled anaesthetic that ablates movement (e.g., withdrawal) in response to surgical incision in 50% of a test population.

The original term, minimal alveolar concentration, referred to an end point that measured the concentration of inhaled anaesthetic required to block purposeful movement in an individual subject.
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