forced expiratory volume


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volume

 [vol´ūm]
the space occupied by a substance or a three-dimensional region; the capacity of such a region or of a container.
blood volume the plasma volume added to the red cell volume; see also blood volume.
closing volume (CV) the volume of gas in the lungs in excess of the residual volume at the time small airways in the dependent portions close during maximal exhalation; see also closing volume.
deficient fluid volume a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as decreased intravascular, interstitial, and/or intracellular fluid. This refers to dehydration, water loss alone without change in sodium. See also fluid volume. Formerly called fluid volume deficit.



When a person engages in normal physical activity and the environmental temperature is 20°C (68°F), the body loses about 2400 ml of water in 24 hours. About 1400 ml are lost in urine, 200 ml in feces, and 100 ml in sweat. The remaining 700 ml are lost through what is called insensible water loss, which takes place by diffusion through the skin and by evaporation from the lungs. About 300 ml of water diffuse through the epithelial cells daily. The lungs excrete about 400 ml per day.

A deficit of fluid volume occurs when there is either an excessive loss of body water or an inadequate compensatory intake. Etiologic factors include active loss through vomiting, diarrhea, gastric suctioning, drainage through operative wounds and tubes, burns, fistulas, hypermetabolic states, and drug-induced diuresis. Insufficient intake of water can be caused by nausea, immobility with inaccessibility of water, and lack of knowledge about the necessity of adequate fluid intake.
Patient Care. Assessment of the patient's hydration status includes monitoring lab data for such signs as increased packed red blood cell volume, increased plasma protein level, elevated specific gravity of urine, and increased blood urea nitrogen (BUN) out of proportion to a change in serum creatinine. In the absence of other problems, the serum sodium should remain within normal limits.



Recording daily weight gives information about the amount of water gained or lost each day. If there is a fluid volume deficit, intake and output measurements can give evidence of fluid imbalance. The urine appears concentrated and is usually well below the criterion of 50 ml of output per hour. Other objective assessment data include hypotension and a decrease in venous filling and in pulse volume and pressure. The mucous membranes are dry, as is the skin, which loses its turgor. The patient may complain of thirst and the body temperature may be elevated.

Patients at risk for profound and potentially fatal fluid volume deficit, as in severe burns, should be assessed frequently for mental acuity status and orientation to person, place, and time. Measures to improve hydration status should take into account the patient's ability to drink and retain fluids by mouth, preferences for certain fluids, and whether hot or cold drinks are preferred. The goal of oral fluid intake should be about 2000 ml per day. Explanations about the importance of an adequate fluid intake and assuring the availability of fresh water and fluids attractive to the patient can help reach the desired goal. Intravenous administration of fluids, especially isotonic saline, may be necessary if oral replacement is not possible. In severe and intractable fluid volume deficit a central venous catheter may be used to evaluate the extent of fluid loss and to guide replacement therapy.
excess fluid volume a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as increased isotonic fluid retention; see also fluid volume. Factors contributing to this include (1) arterial dilatation, as occurs in the inflammatory process; (2) reduced oncotic pressure, as in hypoproteinuria (particularly a deficit of albumin, which is responsible for 80 per cent of oncotic pressure), lymphatic obstruction, and increased capillary permeability, which allows water to escape into the tissues and produce swelling; (3) renal retention of sodium and consequently of water, as seen in renal failure; (4) inadequate circulation of blood through the general circulation, as in congestive heart failure, or through the portal circulation, as in liver failure; and (5) overproduction or administration of adrenocortical hormones.



Hypervolemia can occur when a patient receives excessive fluid replacement or repeated tap water enemas or, much less frequently, drinks more fluids than are eliminated. Characteristics of fluid volume excess include obvious swelling, localized or generalized; weight gain; pulmonary congestion with accompanying shortness of breath, orthopnea, and abnormal breath sounds; a fluid intake greater than output; distended neck veins; and changes in central venous and pulmonary artery pressures.
expiratory reserve volume the maximal amount of gas that can be exhaled from the resting end-expiratory level.
fluid volume the volume of the body fluids, including both intracellular fluid and extracellular fluid.
forced expiratory volume (FEV) the volume that can be exhaled from a full inhalation by exhaling as forcefully and rapidly as possible for a timed period. Times are denoted by subscripts, such as FEV0.5, FEV1.0, FEV2.0, and FEV3.0 for FEV values for 0.5, 1, 2, and 3 seconds.
inspiratory reserve volume the maximal amount of gas that can be inhaled from the end-inspiratory position.
mean corpuscular volume (MCV) the average volume of erythrocytes, conventionally expressed in cubic micrometers or femtoliters (μm3 = fL) per red cell, obtained by multiplying the hematocrit (in l/L) by 1000 and dividing by the red cell count (in millions per μL): MCV = Hct/RBC. Automated electronic blood cell counters generally obtain the MCV directly from the average pulse height of the voltage pulses produced during the red cell count. These instruments obtain the hematocrit indirectly from the equation Hct = MCV × RBC.
minute volume (MV) the quantity of gas exhaled from the lungs per minute; tidal volume multiplied by respiration rate.
packed-cell volume (PCV) hematocrit.
plasma volume the total volume of blood plasma, i.e., the extracellular fluid volume of the vascular space; see also blood volume.
red cell volume the total volume of red cells in the body; see also blood volume.
residual volume (RV) the amount of gas remaining in the lung at the end of a maximal exhalation.
risk for deficient fluid volume a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as being at risk for vascular, cellular, or intracellular dehydration. See also deficient fluid volume.
stroke volume the quantity of blood ejected from a ventricle at each beat of the heart; called also stroke output.
tidal volume the amount of gas passing into and out of the lungs in each respiratory cycle.

forced ex·pi·ra·to·ry vol·ume (FEV),

the maximal volume that can be expired in a specific time interval when starting from maximal inspiration. A subscript annotation normally indicates the number of seconds the patient has been expiring e.g., FEV30-60.

forced expiratory volume (FEV)

the volume of air that can be forcibly expelled in a fixed period after full inspiration. Compare vital capacity. See also expiratory reserve volume.

forced expiratory volume

FEV Pulmonary medicine The maximal amount of air that can be exhaled in a period of time, usually 1–FEV1, or less commonly, 3–FEV3 seconds; FEV1 is usually reduced–and thus is a major parameter measured in obstructive airways disease, a generic term that encompasses asthma and COPD. See Pulmonary function test.

forced ex·pi·ra·to·ry vol·ume

(FEV) (fōrst eks-pī'ră-tōr-ē vol'yūm)
The maximal volume that can be expired in a specific time interval when starting from maximal inspiration.

Forced expiratory volume (FEV1)

The maximum amount of air expired in one second.

forced ex·pi·ra·to·ry vol·ume

(FEV) (fōrst eks-pī'ră-tōr-ē vol'yūm)
Maximal volume of air that can be expired in a specific time interval when starting from maximal inspiration.

forced expiratory volume (FEV),

n the volume of air that can be forcibly expelled in a fixed time after full inspiration.
References in periodicals archive ?
Defined as >120mL more than placebo in forced expiratory volume in one second (FEV1) a standard measure of lung function.
25-75]), forced expiratory volume at one second, ([FEV.
811 (68% of predicted vital capacity) and a forced expiratory volume of 3.
1] (provocative concentration causing a 20% drop in forced expiratory volume in 1 second): 18.
Study participants had a mean baseline forced expiratory volume in 1 second of 33% of predicted, indicative of very severe COPD.
Regarding lung function, transient effects of environmental exposure (as well as diurnal variation, which we controlled for by performing the experiment at the same time) may affect either forced vital capacity (FVC) or forced expiratory volume in 1 sec (FE[V.
Compared with patients receiving treatment with salmeterol plus fluticasone, patients receiving the combination of tiotropium plus formoterol experienced greater improvements in lung function, including superior improvements in forced expiratory volume in one second (FEV1) and Forced Vital Capacity (FVC), two indicators of COPD severity.
Endpoints for the study will include safety, measurements of Forced Expiratory Volume (FEV1 - a measurement of expiratory air flow), and inflammatory markers.
At a meeting in February 2012, the majority of the FDA's Pulmonary-Allergy Drugs Advisory Committee agreed that the data in clinical trials provided evidence that this dose had a clinically meaningful benefit in patients, citing the significant increases in trough forced expiratory volume in 1 second ([FEV.
In our cohort of school age children, breastfeeding was associated with modest improvement in forced mid-expiratory flow (FEF50) in our whole group and with improvements in forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1) only in the children of asthmatic mothers," Claudia E.
46 L (91%); forced expiratory volume in 1 sec ([FEV.
Fineman's poster noted that improvements in forced expiratory volume in one second (FEV1), a measurement of lung function, were significant as early as Day 15 versus placebo (pen0.

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