vascular resistance


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Related to vascular resistance: Peripheral vascular resistance

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.

vas·cu·lar re·sis·tance

(vas'kyū-lăr rē-zis'tăns)
Resistance to flow within the smaller vessels, which is also determined by blood viscosity and the length of the vessels.
References in periodicals archive ?
Owing to the low number of graft losses, we selected the following variables of interest: CP versus IP, terminal vascular resistance, donor terminal sCr levels, and warm ischemic time, which were the strongest independent risk factors for graft failure in the current study [Table 5].
The reduced occlusion blood pressure and increased occlusion vascular resistance in the patients are consistent with previous studies [30-33].
This was further supported by increased total peripheral vascular resistance and reduced dilatory response of brachial artery to endothelial-dependent and -independent stimuli, which is very unlikely in endofibrosis.
By the fortieth day, there is an effective increase in systolic volume and output (WILLIAMS et al., 2007) that occurs due to the reduction in total vascular resistance that accompanies the formation of the uteroplacental vascular system and contributes to increased blood supply to the conceptus (SPOTSWOOD et al., 2006; WILLIAMS et al., 2007).
Differences between the respective values on pulse rate, arterial blood pressure, blood flow, and regional vascular resistance from 37.5 to 41.5[degrees]C were analyzed by the Kruskal-Wallis test, and the Steel method was used for post hoc multiple comparisons at 37.5[degrees]C (Excel Tokei 2008 software, SSRI Co, Tokyo, Japan).
Vascular function was assessed according to traditional clinical measures: (1) resistive component of impedance; (2) reactive component of impedance; and (3) indexed pulmonary vascular resistance (PVRi) changes under 70-100% oxygen ([O.sub.2]) and 20-40 ppm inhaled nitric oxide (iNO) challenge conditions.
During intense exercise, the release of norepinephrine near the alfa-adrenoreceptors of the sympathetic nervous system induces splanchnic vasoconstriction, thereby increasing total splanchnic vascular resistance [19].
While not proven as a first line agent, it has been shown to improve systemic vascular resistance if therapy with norepinephrine fails [4].
The dramatic deterioration in our patient was caused by a progressive cardiac failure with increased vascular resistance and low cardiac index leading to a secondary low-output syndrome.
(8) Pregnancy is associated with voluminous plasma expansion, related to reduced systemic vascular resistance and consequent renin angiotensin system stimulation.
Application of the anastomosis on the anterior interventricular artery was accompanied by a significant decrease in stroke volume (SV), cardiac index (CI), a decrease in blood pressure (BP), an increase in pulmonary capillary wedge pressure, and systemic vascular resistance in the second group.