![Assess capillary refill](https://upload.wikimedia.org/wikipedia/commons/4/48/Assess_capillary_refill.jpg)
Capillary refill time (CRT) is defined as the time taken for color to return to an external
capillary bed
A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...
after pressure is applied to cause
blanching
Blanch or blanching may refer to:
People
* Andrea Blanch (born 1935), portrait, commercial, and fine art photographer
* Arnold Blanch (1896–1968), born and raised in Mantorville, Minnesota
* Stuart Blanch, Baron Blanch (1918–1994), Anglican bi ...
.
It can be measured by holding a hand higher than heart-level and pressing the soft pad of a finger or fingernail until it turns white, then taking note of the time needed for the color to return once pressure is released.
In humans, CRT of more than three seconds indicates decreased peripheral perfusion and may indicate cardiovascular or respiratory dysfunction.
Assessment
In adults
CRT can be measured by applying pressure to the pad of a finger or toe for 5–10 seconds.
It became popularized in the 1980s when Champion et al. proposed a CRT of less than 2 seconds be deemed normal and included CRT in the Trauma Score. The value of 2 seconds for a normal CRT that was proposed by Dr Champion had been arbitrarily chosen by his nurse, and no evidence supporting that value has subsequently been found. CRT has been shown to be influenced by ambient temperature, age, sex, and the anatomical testing and lighting conditions. The most reliable and applicable site for CRT testing is the finger pulp
(not at the fingernail), and the cut-off value for the normal CRT should be 3 seconds,
not 2 seconds.
To assess
shock
Shock may refer to:
Common uses Collective noun
*Shock, a historic commercial term for a group of 60, see English numerals#Special names
* Stook, or shock of grain, stacked sheaves
Healthcare
* Shock (circulatory), circulatory medical emerge ...
, central CRT, which is done by assessing capillary refill time at the sternum, rather than finger CRT, is more useful.
In infants
In newborn
infants
An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
, capillary refill time can be measured by pressing on the
sternum
The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...
for five seconds with a finger or thumb, and noting the time needed for the color to return once the pressure is released (central CRT). The upper normal limit for capillary refill in newborns is 3 seconds. Capillary refill time can also be assessed in animals by pressing on their
gums
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue linin ...
as opposed to the sternum which is generally covered with fur or inaccessible.
A prolonged capillary refill time may be a sign of
shock
Shock may refer to:
Common uses Collective noun
*Shock, a historic commercial term for a group of 60, see English numerals#Special names
* Stook, or shock of grain, stacked sheaves
Healthcare
* Shock (circulatory), circulatory medical emerge ...
and can also indicate dehydration and may be a sign of dengue hemorrhagic fever and
decreased peripheral perfusion
Shock is the state of insufficient blood flow to the tissues of the body as a result of problems with the circulatory system. Initial symptoms of shock may include weakness, fast heart rate, fast breathing, sweating, anxiety, and increased thir ...
. Prolonged capillary refill time may also suggest
peripheral artery disease
Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular diseas ...
.
It is generally accepted that the test is affected by many different external factors and therefore should not be relied upon as a universal diagnostic measure.
In animals
Capillary refill time is also used in veterinary medicine. An animal should have a capillary refill time of less than 1 to 1 3/4 of a second. Because animals have fur, the
gums
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue linin ...
are typically used to test capillary refill time.
Use
Capillary refill time is a quick and cheap way to indicate decreased peripheral perfusion and may indicate cardiovascular or respiratory dysfunction.
It has also been used to assess or diagnose diseases of the peripheral circulatory system such as
Raynaud's syndrome
Raynaud syndrome, also known as Raynaud's phenomenon, eponymously named after the physician Auguste Gabriel Maurice Raynaud, who first described it in his doctoral thesis in 1862, is a medical condition in which the spasm of small arteries cau ...
and
hand–arm vibration syndrome
Vibration white finger (VWF), also known as hand-arm vibration syndrome (HAVS) or dead finger, is a secondary form of Raynaud's syndrome, an industrial injury triggered by continuous use of vibrating hand-held machinery. Use of the term ''vibration ...
.
There is disagreement as to whether the test is useful, however, and it is poorly standardised.
Poor finger or toe capillary refill time is a contraindication for the use of compressive techniques to treat peripheral
oedema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area ma ...
.
In veterinary medicine, poor gum CRT may be an contraindication for use of anaesthesia, as the likelihood of anaesthesia being fatal is higher if there is an underlying heart or lung problem. Gum CRT also used to monitor health during anaesthesia.
See also
*
Peripheral vascular examination
A peripheral vascular examination is a medical examination to discover signs of pathology in the peripheral vascular system. It is performed as part of a physical examination, or when a patient presents with leg pain suggestive of a cardiovascula ...
References
{{DEFAULTSORT:Capillary Refill
Cardiovascular physiology