# shunt

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## shunt

1. a railway point
2. Electronics a low-resistance conductor connected in parallel across a device, circuit, or part of a circuit to provide an alternative path for a known fraction of the current
3. Med a channel that bypasses the normal circulation of the blood: a congenital abnormality or surgically induced
4. Brit informal a collision which occurs when a vehicle runs into the back of the vehicle in front

## Shunt

an electrical or magnetic conductor connected in parallel with an electric or magnetic circuit to divert part of the electric current or magnetic flux when it is undesirable or impossible to pass all the current or flux through the circuit. For example, when a shunt is used to extend the measuring range of an ammeter, the current Ix being measured is divided between the shunt and the ammeter in inverse proportion to their respective resistances, Rs and RA; in this case Ix = IA (1 + RA/RS) = IAks, where IA is the value of the current as determined from the ammeter readings and ks is the shunting factor. For convenience in making current measurements, the resistance of the shunt is chosen so that ks is equal to 10,100, or 1000.

Shunts are manufactured in the form of plates, bands, and wires, primarily of manganin or constantan (for electrical shunts) or of a soft magnetic material (for magnetic shunts).

## shunt

[shənt]
(civil engineering)
To shove or turn off to one side, as a car or train from one track to another.
(electricity)
A precision low-value resistor placed across the terminals of an ammeter to increase its range by allowing a known fraction of the circuit current to go around the meter. Also known as electric shunt.
To place one part in parallel with another.
(electromagnetism)
A piece of iron that provides a parallel path for magnetic flux around an air gap in a magnetic circuit.
(medicine)
A vascular passage by which blood is diverted from its normal circulatory path; frequently it is a surgical passage created between two blood vessels, but it may also be an anatomical feature.

## shunt

To divert, switch or bypass.
References in periodicals archive ?
Contrast TEE performed at the end of the procedure revealed residual right-to-left shunt in 26% of patients: it was mild in 85% of cases and moderate in 15%.
Paradoxical air emboli related to a physiological cardiac right-to-left shunt may cause
Major Finding: Patients who have migraine with aura and a heart with a large right-to-left shunt showed significant deficits in verbal learning and memory, compared with patients with no right-to-left shunting.
A TTE with ASCT was repeated and performed in reversed Trendelenburg position demonstrating a strongly and obvious right-to-left shunt through a PFO (Figure 1).
Jackson, "Pulmonary arteriovenous malformations: effect of embolization on right-to-left shunt, hypoxemia, and exercise tolerance in 66 patients," American Journal of Roentgenology, vol.
Unusual collaterals established between systemic and pulmonary veins presumably due to increased venous pressures causing a right-to-left shunt [1, 3].
In total anomalous pulmonary venous return (TAPVR), the pulmonary veins make an abnormal connection to the right atrium, with coronary sinus or systemic veins resulting physiologically in an extracardiac right-to-left shunt. This anomaly is accompanied by an intracardiac left-to-right shunt through a patent foramen ovale or an atrial septal defect.
Fentanyl helped to blunt catecholamine surges which can lead to an increased right ventricular outflow tract obstruction and right-to-left shunt. Care was taken to avoid hypoxaemia during induction and maintenance in our patient by adjusting inspired oxygen concentration, ensuring adequate hydration, maintenance of systemic arterial blood pressure and avoidance of sudden increases in systemic oxygen demand by maintaining adequate depth of anaesthesia.
(14.) Gas exchange detection of right-to-left shunt in dyspneic patients: Report of three cases Chuang ML, Int J Cardiol.
MIST strengthened the hypothesis that PFO and migraine are linked: More than 60% of the 432 migraineurs screened for the study had a right-to-left shunt. Of those, almost 40% had a moderate or large PFO.
Although results are not finalized, enrollment data show 60% of 370 participants having a right-to-left shunt (versus 27% of the general population) and 38% having a large PFO (versus 7% of the general population).
We present one such case of treatable dyspnea due to patent foramen ovale (PFO) related right-to-left shunt (RLS) in setting of right hemidiaphragm paralysis.

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