Capillary refill time (CRT) is defined as the time taken for color to return to an external capillary bed after pressure is applied to cause blanching. [3] 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. [4] In humans, CRT of more than three seconds indicates decreased peripheral perfusion and may indicate cardiovascular or respiratory dysfunction. [5] 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. [2]
CRT can be measured by applying pressure to the pad of a finger or toe for 5–10 seconds. [6] 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. [7] 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. [8] CRT has been shown to be influenced by ambient temperature, age, sex, and the anatomical testing and lighting conditions. [9] [10] 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. [2]
To assess shock, central CRT, which is done by assessing capillary refill time at the sternum, rather than finger CRT, is more useful. [6]
In newborn infants, capillary refill time can be measured by pressing on the sternum 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. [11] A prolonged capillary refill time may be a sign of shock and can also indicate dehydration and may be a sign of dengue hemorrhagic fever and decreased peripheral perfusion. [12] Prolonged capillary refill time may also suggest peripheral artery disease. [4] 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. [3]
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 are typically used to test capillary refill time. [13]
Capillary refill time is a quick and cheap way to indicate decreased peripheral perfusion and may indicate cardiovascular or respiratory dysfunction. [5] It has also been used to assess or diagnose diseases of the peripheral circulatory system such as Raynaud's syndrome and hand–arm vibration syndrome. [6] There is disagreement as to whether the test is useful, however, and it is poorly standardised. [14] [6] Poor finger or toe capillary refill time is a contraindication for the use of compressive techniques to treat peripheral oedema. Capillary refill time is traditionally used as a clinical indicator of tissue vascularity either after limb injury or after revascularization [15] and 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. [2]
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. [16]
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either generalized, affecting the whole body, or local, affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise.
The Valsalva maneuver is performed by a forceful attempt of exhalation against a closed airway, usually done by closing one's mouth and pinching one's nose shut while expelling air, as if blowing up a balloon. Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to clear the ears and sinuses when ambient pressure changes, as in scuba diving, hyperbaric oxygen therapy, or air travel.
Cyanosis is the change of body tissue color to a bluish-purple hue, as a result of decrease in the amount of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Cyanosis is apparent usually in the body tissues covered with thin skin, including the mucous membranes, lips, nail beds, and ear lobes. Some medications may cause discoloration such as medications containing amiodarone or silver. Furthermore, mongolian spots, large birthmarks, and the consumption of food products with blue or purple dyes can also result in the bluish skin tissue discoloration and may be mistaken for cyanosis. Appropriate physical examination and history taking is a crucial part to diagnose cyanosis. Management of cyanosis involves treating the main cause, as cyanosis isn’t a disease, it is a symptom.
A nail is a protective plate characteristically found at the tip of the digits of all primates, corresponding to the claws in other tetrapod animals. Fingernails and toenails are made of a tough rigid protein called alpha-keratin, a polymer also found in the claws, hooves and horns of vertebrates.
Nail clubbing, also known as digital clubbing or clubbing, is a deformity of the finger or toe nails associated with a number of diseases, anomalies and defects; some congenital. This is mostly of the heart and lungs. When it occurs together with joint effusions, joint pains, and abnormal skin and bone growth it is known as hypertrophic osteoarthropathy.
The prothrombin time (PT) – along with its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) – is an assay for evaluating the extrinsic pathway and common pathway of coagulation. This blood test is also called protime INR and PT/INR. They are used to determine the clotting tendency of blood, in such things as the measure of warfarin dosage, liver damage, and vitamin K status. PT measures the following coagulation factors: I (fibrinogen), II (prothrombin), V (proaccelerin), VII (proconvertin), and X.
Pulse oximetry is a noninvasive method for monitoring blood oxygen saturation. Peripheral oxygen saturation (SpO2) readings are typically within 2% accuracy of the more accurate reading of arterial oxygen saturation (SaO2) from arterial blood gas analysis.
Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue. Perfusion may also refer to fixation via perfusion, used in histological studies. Perfusion is measured as the rate at which blood is delivered to tissue, or volume of blood per unit time per unit tissue mass. The SI unit is m3/(s·kg), although for human organs perfusion is typically reported in ml/min/g. The word is derived from the French verb perfuser, meaning to "pour over or through". All animal tissues require an adequate blood supply for health and life. Poor perfusion (malperfusion), that is, ischemia, causes health problems, as seen in cardiovascular disease, including coronary artery disease, cerebrovascular disease, peripheral artery disease, and many other conditions.
In medicine, Allen's test or the Allen test is a medical sign used in physical examination of arterial blood flow to the hands. It was named for Edgar Van Nuys Allen, who described the original version of the test in 1942.
Colic in horses is defined as abdominal pain, but it is a clinical symptom rather than a diagnosis. The term colic can encompass all forms of gastrointestinal conditions which cause pain as well as other causes of abdominal pain not involving the gastrointestinal tract. What makes it tricky is that different causes can manifest with similar signs of distress in the animal. Recognizing and understanding these signs is pivotal, as timely action can spell the difference between a brief moment of discomfort and a life-threatening situation. The most common forms of colic are gastrointestinal in nature and are most often related to colonic disturbance. There are a variety of different causes of colic, some of which can prove fatal without surgical intervention. Colic surgery is usually an expensive procedure as it is major abdominal surgery, often with intensive aftercare. Among domesticated horses, colic is the leading cause of premature death. The incidence of colic in the general horse population has been estimated between 4 and 10 percent over the course of the average lifespan. Clinical signs of colic generally require treatment by a veterinarian. The conditions that cause colic can become life-threatening in a short period of time.
Vital signs are a group of the four to six most crucial medical signs that indicate the status of the body's vital (life-sustaining) functions. These measurements are taken to help assess the general physical health of a person, give clues to possible diseases, and show progress toward recovery. The normal ranges for a person's vital signs vary with age, weight, sex, and overall health.
Cerebral perfusion pressure, or CPP, is the net pressure gradient causing cerebral blood flow to the brain. It must be maintained within narrow limits because too little pressure could cause brain tissue to become ischemic, and too much could raise intracranial pressure (ICP).
Hyperviscosity syndrome is a group of symptoms triggered by an increase in the viscosity of the blood. Symptoms of high blood viscosity include spontaneous bleeding from mucous membranes, visual disturbances due to retinopathy, and neurologic symptoms ranging from headache and vertigo to seizures and coma.
The mental nerve is a sensory nerve of the face. It is a branch of the posterior trunk of the inferior alveolar nerve, itself a branch of the mandibular nerve (CN V3), itself a branch of the trigeminal nerve (CN V). It provides sensation to the front of the chin and the lower lip, as well as the gums of the anterior mandibular (lower) teeth. It can be blocked with local anaesthesia for procedures on the chin, lower lip, and mucous membrane of the inner cheek. Problems with the nerve cause chin numbness.
A pulmonary shunt is the passage of deoxygenated blood from the right side of the heart to the left without participation in gas exchange in the pulmonary capillaries. It is a pathological condition that results when the alveoli of parts of the lungs are perfused with blood as normal, but ventilation fails to supply the perfused region. In other words, the ventilation/perfusion ratio of those areas is zero.
Hoffmann's reflex is a neurological examination finding elicited by a reflex test which can help verify the presence or absence of issues arising from the corticospinal tract. It is named after neurologist Johann Hoffmann. Usually considered a pathological reflex in a clinical setting, the Hoffmann's reflex has also been used as a measure of spinal reflex processing (adaptation) in response to exercise training.
Muehrcke's nails or Muehrcke's lines are changes in the fingernail that may be a sign of an underlying medical condition. The term refers to a set of one or more pale transverse bands extending all the way across the nail, parallel to the lunula. In contrast to Beau's lines, they are not grooved, and in contrast to Mees' lines, the thumb is usually not involved.
Clotting time is a general term for the time required for a sample of blood to form a clot, or, in medical terms, coagulate. The term "clotting time" is often used when referring to tests such as the prothrombin time (PT), activated partial thromboplastin time, activated clotting time (ACT), thrombin time (TT), or Reptilase time. These tests are coagulation studies performed to assess the natural clotting ability of a sample of blood. In a clinical setting, healthcare providers will order one of these tests to evaluate a patient's blood for any abnormalities in the time it takes for their blood to clot. Each test involves adding a specific substance to the blood and measuring the time until the blood forms fibrin which is one of the first signs of clotted blood. Each test points to a different component of the clotting sequence which is made up of coagulation factors that help form clots. Abnormal results could be due to a number of reasons including, but, not limited to, deficiency in clotting factors, dysfunction of clotting factors, blood-thinning medications, medication side-effects, platelet deficiency, inherited bleeding or clotting disorders, liver disease, or advanced illness resulting in a medical emergency known as disseminated intravascular coagulation (DIC).
Dental pulpal testing is a clinical and diagnostic aid used in dentistry to help establish the health of the dental pulp within the pulp chamber and root canals of a tooth. Such investigations are important in aiding dentists in devising a treatment plan for the tooth being tested.
Chronic limb threatening ischemia (CLTI), also known as critical limb ischemia (CLI), is an advanced stage of peripheral artery disease (PAD). It is defined as ischemic rest pain, arterial insufficiency ulcers, and gangrene. The latter two conditions are jointly referred to as tissue loss, reflecting the development of surface damage to the limb tissue due to the most severe stage of ischemia. Compared to the other manifestation of PAD, intermittent claudication, CLI has a negative prognosis within a year after the initial diagnosis, with 1-year amputation rates of approximately 12% and mortality of 50% at 5 years and 70% at 10 years.
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