pulmonary vascular resistance


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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 RA or RAW.
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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

pul·mo·nar·y vas·cu·lar re·sis·tance

(pul'mŏ-nar-ē vas'kyū-lăr rĕ-zistăns)
The resistance to blood flow through the pulmonary circulation, which is largely influenced by the degree of tone or caliber of the pulmonary arteries and capillaries. Can be measured with the use of hemodynamic monitoring.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
(28) Detection of PAH with underlying genetic mutations is important because individuals with BMPR2 mutations tend to present at a younger age, have higher pulmonary vascular resistance, have a failure of response to vasodilators, and are more likely to succumb to the disease at an earlier age with more-severe disease.
Double flap patch closure of VSD with elevated pulmonary vascular resistance: an experience at AFIC/ NIHD.
The parameters studied include the pulmonary vascular resistance ([R.sub.pul]), the arteriolar resistance of the lower body ([R.sub.art_1]), and the ventricular maximum active elastance ([E.sub.slv]) in systole and baseline passive elastance ([E.sub.dlv]) in diastole.
The pulmonary vascular resistance was calculated after ventilation with Fi[O.sub.2] at 1.0 and is also presented in Table 1.
Individuals with scleroderma-associated PAH and idiopathic PAH both demonstrate elevated pulmonary artery pressures, increased pulmonary vascular resistance, and subsequent reductions in pulmonary perfusion and cardiac output that result in dyspnea, exercise intolerance, inactivity, and deconditioning.
Shandas, Extraction of pulmonary vascular compliance, pulmonary vascular resistance, and right ventricular work from single-pressure and Doppler flow measurements in children with pulmonary hypertension: a new method for evaluating reactivity: in vitro and clinical studies.
(2) Right-heart catheterization allows pressures and cardiac output to be accurately measured, and pulmonary vascular resistance to be calculated.
Exposure to concentrated ambient particles (CAPs; median, 182.75 big/[m.sup.3]) for 5 hr/day for 3 days decreased the lumen:wall area ratio of small pulmonary arteries in rats, indicating increased pulmonary vascular resistance (Batalha et al.
Only with oxygen do newborn infants achieve optimal increase in pulmonary blood flow and reduction in pulmonary vascular resistance; whether 21% oxygen is sufficient in all cases is yet to be demonstrated.
Neither elevated pulmonary vascular resistance, sensitization, prior support with a left ventricular assist device, nor a history of previous heart transplant influenced overall survival rates, according to a review of 536 patients who received heart transplants between 1993 and 1999 at Columbia University College of Physicians and Surgeons in New York.
Primary pulmonary hypertension (PPH) is diagnosed when PH is accompanied with increased pulmonary vascular resistance (PVR) in the absence of other diseases of the lungs or heart.
Infants born with meconium are more likely to have changes in pulmonary vascular resistance. This can lead to severe meconium aspiration syndrome with persistent pulmonary hypertension and a cycle of acidosis and hypoxia that can be relieved only with extra corporeal membrane oxygenation.

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