airway resistance

resistance /re·sis·tance/ (re-zis´tans)

1. opposition, or counteracting force.

2. the natural ability of an organism to resist microorganisms or toxins produced in disease.

3. the opposition to the flow of electrical current between two points of a circuit. Symbol R or .

4. in psychiatry, conscious or unconscious defenses that prevent material in the unconscious from coming into awareness.

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airway resistance  the opposition of the tracheobronchial tree to air flow. Symbols RA, RAW.

androgen resistance  resistance of target organs to the action of androgens; the result is any of a spectrum of defects. In mild to incomplete types the person may have a definite male phenotype but infertility, or may have ambiguous genitalia. In the complete type the person has a female phenotype but XY chromosomes.

drug resistance  the ability of a microorganism to withstand the effects of a drug that are lethal to most members of its species.

electrical resistance  resistance (3).

multidrug resistance , multiple drug resistance in some malignant cell lines, resistance to many structurally unrelated chemotherapy agents in cells that have developed natural resistance to a single cytotoxic compound.

vascular resistance  the opposition to blood flow in a vascular bed.

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airway resistance (R_aw),

a measure of the impedance to airflow through the bronchopulmonary system. It is the reciprocal of airway conductance.

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resistance [re-zis´tans]

1. opposition, or counteracting force, as opposition of a conductor to passage of electricity or other energy or substance.

2. the natural ability of a normal organism to remain unaffected by noxious agents in its environment; see also immunity.

3. in psychology or psychiatry, conscious or unconscious defenses against change, preventing repressed material from coming into awareness; they can take such forms as forgetfulness, evasions, embarrassment, mental blocks, denial, anger, superficial talk, intellectualization, or intensification of symptoms. It occurs because the blocked association or understanding would be too threatening to face at this point in the therapy; identification of what point the resistance comes at can be an important indicator of the patient's unconscious patterns.

airway resistance the opposition of the tissues of the air passages to air flow: the mouth-to-alveoli pressure difference divided by the rate of air flow. Symbol R_A or R_AW.

androgen resistance resistance of target organs to the action of androgens, resulting in any of a spectrum of defects from a normal male phenotype in which men have normal genitalia but infertility to complete androgen resistance in which the individual has a female phenotype. Complete androgen resistance is an extreme form of male pseudohermaphroditism in which the individual is phenotypically female but is of XY chromosomal sex; there may be rudimentary uterus and tubes, but the gonads are typically testes, which may be abdominal or inguinal in position. Called also testicular feminization and testicular feminization syndrome. Incomplete androgen resistance is any of various forms less than the complete type, manifested by a male phenotype with various degrees of ambiguous genitalia such as hypospadias and a small vaginal pouch, a hooded phallus, or a bifid scrotum that may or may not contain gonads.

drug resistance the ability of a microorganism to withstand the effects of a drug that are lethal to most members of its species.

insulin resistance see insulin resistance.

multidrug resistance (multiple drug resistance) a phenomenon seen in some malignant cell lines: cells that have developed natural resistance to a single cytotoxic compound are also resistant to structurally unrelated chemotherapy agents. Called also cross-resistance.

peripheral resistance resistance to the passage of blood through the small blood vessels, especially the arterioles.

pulmonary vascular resistance the vascular resistance of the pulmonary circulation; the difference between the mean pulmonary arterial pressure and the left atrial filling pressure divided by the cardiac output. Called also total pulmonary vascular resistance.

total peripheral resistance the vascular resistance of the systemic circulation: the difference between the mean arterial pressure and central venous pressure divided by the cardiac output.

total pulmonary resistance (total pulmonary vascular resistance) pulmonary vascular resistance.

vascular resistance the opposition to blood flow in a vascular bed; the pressure drop across the bed divided by the blood flow, conventionally expressed in peripheral resistance units. Symbol R or R.

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airway,

n 1. a clear passageway for air into and out of the lungs.
2. a device for securing unobstructed respiration during general anesthesia or in states of unconsciousness.

airway, chin lift,

n a method of opening the trachea of an individual by manually changing the position of his or her head in order to perform rescue breathing.

airway obstruction,

n an abnormal condition of the respiratory pathway characterized by a mechanical impediment to the delivery or to the absorption of oxygen in the lungs, as in choking, bronchospasm, obstructive lung disease, or laryngospasm.

airway obstruction, chest thrust,

n an alternate method of removing an obstacle lodged in the airway by compressing the sternum; used when pregnancy or a patient's body size render the Heimlich maneuver impossible or inappropriate. See Heimlich maneuver.

airway obstruction, infant chest thrust,

n a method of removing an obstacle lodged in the airway of an infant by placing the child facedown along the forearm and striking the child's back with the opposite hand. See Heimlich maneuver.

airway resistance,

n the ratio of pressure difference between the oral cavity, nose, or other airway opening and the alveoli to the simultaneously measured resulting volumetric gas flow rate.

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airway

1. the passage by which air enters and leaves the lungs.

2. a mechanical device used for securing unobstructed respiration during general anesthesia or other occasions in which the patient is not ventilating or exchanging gases properly. Includes an endotracheal tube and a tracheostomy tube.

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artificial airway

endotracheal or tracheostomy tubes.

airway obstruction

in the unanesthetized animal is usually caused by vomitus or laryngeal spasm due to foreign material in the larynx. In the nonintubated anesthetized animal, it is caused by caudal displacement of the tongue and epiglottis, accumulation of mucus, saliva and blood in the pharynx or laryngeal spasm resulting from that accumulation. In the intubated animal, faulty placement or functioning of the endotracheal tube or kinking of it can cause obstruction of the airway. The signs of obstruction are deep, asphyxial respirations, struggling and great agitation in the conscious animal. Deeply anesthetized animals simply show a decline in respiratory efficiency.

airway reflexes

aid in the removal of secretions and foreign material. See also cough, sneeze.

airway resistance

the resistance to airflow through the respiratory tree and any addition to the airway, such as the endotracheal tube and connectors in a closed circuit anesthetic machine.

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airway resistance

Lung physiology A measure of the resistance–in cm H₂O to the flow–in L/min of air in upper airways, the result of natural recoil–resiliency of anatomic structures–oro- and nasopharynx, larynx, and nonrespiratory portions of the lungs–trachea, bronchi, and bronchioles through which air passes on the way to the alveoli; assessment of AR evaluates airway responsiveness, provocation testing–eg bronchial challenge, evaluation of sites of airflow resistance or closures, and characterization of the type of lung disease; airway resistance is ↑, either focally or globally in asthma, COPD, and smokers. See Airway responsiveness, Asthma, COPD.