Perfusion

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List of terms related to Perfusion

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In physiology, perfusion is the process of nutritive delivery of arterial blood to a capillary bed in the biological tissue. The word is derived from the French verb "perfuse" meaning to "pour over or through."

Tests of adequate perfusion are a part of patient triage performed by medical or emergency personnel in a mass casualty incident.

## Contents

* 1 Calculation
* 2 Overperfusion and underperfusion
* 3 Measurement using fMRI
* 4 See also
* 5 References
* 6 External links

## Calculation

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Perfusion ("F") can be measured with the following formula, where Pa is mean arterial pressure, Pv is mean venous pressure, and R is vascular resistance: [1]

<math>F = \frac{ P_A - P_V }{ R} </math>

The term "Pa - Pv" is sometimes presented as "ΔP", for the change in pressure.[2]

The terms "perfusion" and "perfusion pressure" are sometimes used interchangeably, but the equation should make clear that resistance can have an effect on the perfusion, but not on the perfusion pressure.

## Overperfusion and underperfusion

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The terms "overperfusion" and "underperfusion" are measured relative to the average level of perfusion across all tissues in an individual body, and the terms should not be confused with hypoperfusion and "hyperperfusion", which measure the perfusion level to the tissue's current need.

Tissues like the skin are considered overperfused and receive more blood than would be expected to meet the metabolic needs of the tissue. In the case of the skin, extra blood flow is used for thermoregulation. In addition to delivering oxygen, the blood helps dissipate heat by redirecting warm blood close to the surface where it can cool the body through the sweating and thermal radiation.

## Measurement using fMRI

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Two main categories of functional magnetic resonance imaging (fMRI) techniques can be used to measure tissue perfusion in vivo.

* The first is based on the use of injected contrast agent that changes the magnetic susceptibility of blood and thereby the MR signal which is repeatedly measured during bolus passage.
* The other category is based on Arterial spin labeling (ASL), where arterial blood is magnetically tagged before it enters into the tissue of interest and the amount of labeling is measured and compared to a control recording obtained without spin labeling.

## See also

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* Reperfusion injury

## References

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1. ↑ Richard E. Klabunde. "Cardiovascular Physiology Concepts".
2. ↑ Essentials of Human Physiology by Thomas M. Nosek. Section 7/7ch04/7ch04p26. - "Renal Perfusion Pressure and Vascular Resistance"

## External links

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* Perfusion Protocol (requires Adobe Acrobat Reader)

* v
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Cardiovascular disease (heart)

Ischaemic|

| Coronary disease|

* Coronary artery disease (CAD)
* Coronary artery aneurysm
* Spontaneous coronary artery dissection (SCAD)
* Coronary thrombosis
* Coronary vasospasm
* Myocardial bridge

|

Active ischemia|

* Angina pectoris
* Prinzmetal's angina
* Stable angina
* Acute coronary syndrome
* Myocardial infarction
* Unstable angina

Sequelae|

* hours
* Hibernating myocardium
* Myocardial stunning
* days
* Myocardial rupture
* weeks
* Aneurysm of heart / Ventricular aneurysm
* Dressler syndrome

Layers|

| Pericardium|

* Pericarditis
* Acute
* Chronic / Constrictive
* Pericardial effusion
* Cardiac tamponade
* Hemopericardium

|

Myocardium|

* Myocarditis
* Chagas disease
* Cardiomyopathy
* Dilated
* Alcoholic
* Hypertrophic
* Tachycardia-induced
* Restrictive
* Loeffler endocarditis
* Cardiac amyloidosis
* Endocardial fibroelastosis
* Arrhythmogenic right ventricular dysplasia

Endocardium /
valves|

| Endocarditis|

* infective endocarditis
* Subacute bacterial endocarditis
* non-infective endocarditis
* Libman–Sacks endocarditis
* Nonbacterial thrombotic endocarditis

|

Valves|

* mitral
* regurgitation
* prolapse
* stenosis
* aortic
* stenosis
* insufficiency
* tricuspid
* stenosis
* insufficiency
* pulmonary
* stenosis
* insufficiency

Conduction /
arrhythmia|

| Bradycardia|

* Sinus bradycardia
* Sick sinus syndrome
* Heart block: Sinoatrial
* AV
* 1°
* 2°
* 3°
* Intraventricular
* Bundle branch block
* Right
* Left
* Left anterior fascicle
* Left posterior fascicle
* Bifascicular
* Trifascicular
* Adams–Stokes syndrome

|

Tachycardia
(paroxysmal and sinus)|

| Supraventricular|

* Atrial
* Multifocal
* Junctional
* AV nodal reentrant
* Junctional ectopic

|

Ventricular|

* Accelerated idioventricular rhythm
* Catecholaminergic polymorphic
* Torsades de pointes

Premature contraction|

* Atrial
* Junctional
* Ventricular

Pre-excitation syndrome|

* Lown–Ganong–Levine
* Wolff–Parkinson–White

Flutter / fibrillation|

* Atrial flutter
* Ventricular flutter
* Atrial fibrillation
* Familial
* Ventricular fibrillation

Pacemaker|

* Ectopic pacemaker / Ectopic beat
* Multifocal atrial tachycardia
* Pacemaker syndrome
* Parasystole
* Wandering atrial pacemaker

Long QT syndrome|

* Andersen–Tawil
* Jervell and Lange-Nielsen
* Romano–Ward

Cardiac arrest|

* Sudden cardiac death
* Asystole
* Pulseless electrical activity
* Sinoatrial arrest

Other / ungrouped|

* hexaxial reference system
* Right axis deviation
* Left axis deviation
* QT
* Short QT syndrome
* T
* T wave alternans
* ST
* Osborn wave
* ST elevation
* ST depression
* Strain pattern

Cardiomegaly|

* Ventricular hypertrophy
* Left
* Right / Cor pulmonale
* Atrial enlargement
* Left
* Right
* Athletic heart syndrome

Other|

* Cardiac fibrosis
* Heart failure
* Diastolic heart failure
* Cardiac asthma
* Rheumatic fever

* v
* t
* e

Respiratory system, physiology: respiratory physiology

Lung volumes|

VC * FRC * Vt * dead space * CC

calculations: respiratory minute volume * FEV1/FVC ratio

devices: spirometry * body plethysmography * peak flow meter

Airways/
ventilation (V)|

positive pressure ventilation * breath (inhalation, exhalation) * respiratory rate * respirometer * pulmonary surfactant * compliance * hysteresivity * airway resistance * bronchial hyperresponsiveness * bronchial challenge test * bronchoconstriction/bronchodilation

Blood/
perfusion (Q)|

pulmonary circulation * hypoxic pulmonary vasoconstriction * pulmonary shunt

Interactions/
ventilation/perfusion ratio (V/Q)|

ventilation/perfusion scan * zones of the lung * gas exchange * pulmonary gas pressures * alveolar gas equation * alveolar-arterial gradient * hemoglobin * oxygen-haemoglobin dissociation curve (2,3-DPG, Bohr effect, Haldane effect) * carbonic anhydrase (chloride shift) * oxyhemoglobin * respiratory quotient * arterial blood gas * diffusion capacity * DLCO

Control of respiration|

pons (pneumotaxic center, apneustic center) * medulla (dorsal respiratory group, ventral respiratory group) * chemoreceptors (central, peripheral) * pulmonary stretch receptors (Hering-Breuer reflex)

Insufficiency|

high altitude * oxygen toxicity * hypoxia

de:Perfusion

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