Kinds of Medical Thermometers

MEDICAL THERMOMETER aesculapian thermometers atomic number 18 utilise for measuring human body temperature, with the tip of the thermometer being inserted either into the mouth infra the tongue (oral or sub-lingual temperature), under the armpit (axillary temperature), or into the rectum via the anus (rectal temperature). CLASSIFICATION BY TECHNOLOGY Liquid-filled The traditional thermometer is a glass furnish-shaped structure with a bulb at unmatched end containing a liquid which expands in a uniform manner with temperature. The tube itself is narrow (capillary) and has calibration markings a big it.The liquid is often mercury, only alcohol thermometers use a colored alcohol. Medically, a maximum thermometer is often used, which indicates the maximum temperature reached even afterwards it is removed from the body. To use the thermometer, the bulb is situated in the location where the temperature is to be measured and left long enough to be certain to reach thermal equalis ertypically three minutes. Maximum-reading is achieved by gist of a constriction in the neck close to the bulb. As the temperature of the bulb rises, the liquid expands up the tube through the constriction.When the temperature falls, the column of liquid breaks at the constriction and lav non go by to the bulb, thus remaining stationary in the tube. After reading the value, the thermometer must(prenominal) be reset by repeatedly swinging it sharply to stir up the liquid back through the constriction. Mercury Mercury-in-glass thermometers have been considered the most absolute liquid-filled types. However, mercury is a cyanogenetic heavy metal, and mercury has only been used in clinical thermometers if protected from breakage of the tube.The tube must be very narrow to minimize the amount of mercury in itthe temperature of the tube is not controlled, so it must contain very much less mercury than the bulb to minimize the effect of the temperature of the tubeand this makes the reading rather difficult as the narrow mercury column is not very visible. profile is less of a problem with a coloured liquid. In the 1990s it was decided by whom? that mercury-based thermometers were too equivocal to handle the vigorous swinging needed to reset a mercury maximum thermometer makes it easy to by the bye break it and spill the moderately poisonous mercury.Mercury thermometers have largely been replaced by electronic digital thermometers, or, more r arly, thermometers based on liquids other than mercury (such as galinstan, coloured alcohols and heat-sensitive liquid crystals). Electronic or digital Since compact and inexpensive methods of measuring and displaying temperature became available, electronic thermometers (often called digital, because they display numeric values) have been used. Many display readings to nifty precision (0. 1C or 0. F, whatevertimes half that), only if this should not be interpreted as a guarantee of the true qualify accuracy must be canvass in documentation and maintained by periodical recalibration. A typical inexpensive electronic capitulum thermometer for topographic point use has a displayed resolution of 0. 1C, hardly a stated accuracy within 0. 2C when new. 1 The first electronic clinical thermometer, invented in 1954, used a flexible probe that contained a Carboloy thermistor. 2 Contact Some electronic thermometers may work by contact (the electronic detector is placed in the location where temperature is to be measured, and left long enough to reach equilibrium).These typically reach equilibrium faster than mercury thermometers the thermometer may beep when equilibrium has been reached, or the time may be specified in the manufacturers documentation. Remote Other electronic thermometers work by remote sensing an infr ard sensor responds to the radiation spectrum emitted from the location. Although these are not in direct contact with the area being measured, they may quench contact part of the b ody (a thermometer which senses the temperature of the eardrum without touching it is inserted into the ear canal).To eliminate the risk of patient cross-infection, liquid probe covers and single-use clinical thermometers of all types are used in clinics and hospitals. Basal thermometer A basal thermometer is a thermometer used to take the basal (base) body temperature, the temperature upon waking. Basal body temperature is much less affected than daylight temperature by environmental factors such as exercise and food intake. This allows small changes in body temperature to be detected, such as those caused by ovulation 3 or changes in thyroid function citation needed. Glass oral thermometers typically have markings every 0. 1C or 0. F. Basal temperature is horse barn enough to require accuracy of at least 0. 05C or 0. 1F, so special glass basal thermometers are distinct from glass oral thermometers. Digital thermometers which have sufficient resolution (0. 05C or 0. 1F is suffici ent) may be suitable for monitoring basal body temperatures the specification should be checked to ensure absolute accuracy, and thermometers (like most digital instruments) should be calibrated at specified intervals. If only the renewal of basal temperature is required, absolute accuracy is not so important so long as the readings do not have large variability (e. . , if real temperature varies from 37. 00C to 37. 28C, a thermometer which inaccurately but consistently reads a change from 37. 17C to 37. 45C will indicate the order of magnitude of the change). Some digital thermometers are marketed as basal thermometers and have extra features such as a larger display, expanded memory functions, or beeping to confirm the thermometer is placed properly. CLASSIFICATION BY LOCATION The temperature can be measured in various locations on the body which maintain a fairly stable temperature (mainly sub-lingual, axillary, rectal, vaginal, forehead, or temporal artery).The normal temperatu re varies slightly with the location an oral reading of 37C does not correspond to rectal, temporal, etc. readings of the same value. When a temperature is quoted the location should also be specified. If a temperature is stated without reserve (e. g. , typical body temperature) it is usually assumed to be sub-lingual. The differences between core temperature and measurements at different locations, cognize as clinical bias, are discussed in the article on normal human body temperature.Measurements are subject to both site-dependent clinical bias and variability between a series of measurements (standard deviations of the differences). For example, one teaching found that the clinical bias of rectal temperatures was greater than for ear temperature measured by a weft of thermometers under test, but variability was less. 4 Oral Oral temperature may only be taken from a patient who is capable of holding the thermometer securely under the tongue, which generally excludes small chil dren or people who are unconscious or overcome by coughing, weakness, or vomiting. This is less of a problem with fast-reacting digital thermometers, but is certainly an issue with mercury thermometers, which take several minutes to stabilize their reading. ) If the patient has drunk a hot or cold liquid beforehand time must be allowed for the mouth temperature to return to its normal value. 5 The typical range of a sub-lingual thermometer for use in humans is from about 35C to 42C or 90F to 110F. Armpit The Armpit (axillary) temperature is measured by holding the thermometer tightly under the armpit. One needs to hold the thermometer for several minutes to get an accurate measurement.Rectal Rectal temperature-taking, especially if performed by a person other than the patient, should be facilitated with the use of a water-based personalised lubricant. Although rectal temperature is the most accurate, this method may be considered unpleasant or embarrassing in some countries or cult ures, especially if used on patients older than young children also, if not taken the correct way, rectal temperature-taking can be uncomfortable and in some cases painful for the patient. Rectal temperature-taking is considered the method of choice for infants. 6 capitulum Other kinds of medical thermometers exist, such as the tympanic thermometer that measures the temperature of the tympanum by infrared measurement, The thermometer has a acoustic projection (protected by a one-time hygienic sheath) which contains the infrared probe the projection is gently placed in the ear canal and a button pressed the temperature is read and displayed within about a second. These thermometers are used both in the home (models are available for prices starting at around 20 USD) and in medical facilities. Temporal arteryA newer development is the Temporal artery thermometer, which uses the infrared principle to accurately report a patients temperature, with comparable accuracy to rectal thermome try. citation needed Forehead The band thermometer is applied to the patients brow. It is typically a band coat with different temperature-sensitive markings using liquid-crystal or similar technology at a given temperature the markings (numerals indicating the temperature) in one region are at the right temperature to become visible. This type gives an indication of fever, but is not considered accurate.