Clinical thermometers

Povidone—iodine is a brown, water-soluble powder containing approximately 10% iodine. However, the amount of free iodine, which is responsible for the antimicrobial activity, is low in a concentrated solution, but is released as the solution is diluted (41). Concentrated solutions have actually been contaminated with bacteria (42). For use as an antiseptic, povidine—iodine is diluted with water or alcohol to a concentration of 1% iodine. Detergents are added if it is used as a surgical scmb. lodophors are important as broad-spectmm antiseptics for the skin, although they do not have the persistent action of some other antiseptics. They are also used as disinfectants for clinical thermometers that have been used by tuberculous patients, for surface disinfection of tables, etc, and for clean equipment in hospitals, food plants, and dairies, much as chlorine disinfectants are used. 

Ethanol and 2-propanol have also found use ia disinfecting clinical thermometers, and as preservatives to prevent microbial deterioration of cosmetics and mediciaals. They are sometimes combiaed with other disiafectants, namely formaldehyde (69), phenoHcs (70), chlorhexidine (71), hypochlorite (72), and phenols (70). 

Temperature Recording. Use an accurate temperature-sensing device, such as a clinical thermometer or thermistor or similar probe, that has been calibrated to ensure an accuracy of 0.1° and has been tested to determine that a maximum reading is reached in less than 5 min. Insert the temperature-sensing probe into the rectum of the test rabbit to a depth of not less than 7.5 cm and, after a period of time not less than that previously determined as sufficient, record the rabbit s temperature. 

For the initial pyrogen tests, groups of three healthy, mature rabbits are chosen. Accurate temperature-sensing devices, such as clinical thermometers or thermistor probes, are inserted into the rectum of the rabbits to record their body temperature. If these probes remain inserted throughout the test period, the rabbits must be restrained with light-fitting neck stocks that permit them to move about. During the test, food but not water is withheld from the animals. 

Tang N, Li YM. Neurotoxic effects in workers of the clinical thermometer manufacture plant. IntJ Occup Med Environ Plealth 2006 19(3) 198 202. 

Fahrenheit determined the boiling point of water to be 212° using his scale, and subsequently modified the freezing point of water to 32° to represent the interval between these two points by 180°, a more rational number than 182°. Body temperature was later modified on the scale to 98.6°, the normal human temperature denoted on clinical thermometers in the United States today. Except for the United States, where thermometers using the Fahrenheit scale are standard for clinical and meteorological reporting, the Fahrenheit scale is no longer in use. 

In conclusion, the last 10 years has seen a greatly increased interest in temperature measurement, particularly in the use of thermistors in everything from clinical thermometers, thermal dilution catheters, water-bath regulators, hand-held digital thermometers, and, finally, an absolute temperature standard. We can look forward in the next 10 years to bringing temperature standardization to all areas of chemistry, biochemistry and clinical chemistry, as well as to the pasteurization and virus kill point for vaccines. For the present recommendations in biochemistry, see Expert Panel on Enzymes (1975). 

Among the first commercial thermometers were those manufactured by Fahrenheit with mercury. The advantages of mercury over most other fluids include its very low vapor pressure, excellent temperature range—from —38 °C to 650 °C—and short response time. Short response time is a convenient, if not important, factor with respect to medical applications. Although Sanctorius thermoscope was used for medical purposes up until 1866, clinical thermometers were 300 mm long and took 20 min to record a patient s temperature. In 1866, Albutt invented a thermometer half that length that required only 5 min (Adler, 1974). 

Clinical thermometers are classified as partial immersion thermometers since only bulb and part of the stem enter the mouth. Optimally, the thermometer is calibrated and an immersion line is etched onto the side of the stem to indicate to what point the thermometer should be immersed. This type of thermometer is best for a narrow temperature range (such as for measuring body temperature) since the expected variation in temperature is much less than 10 °C. Total immersion thermometers are those in which it is immersed to the same level as the height of the liquid column of the thermometer. The entire thermometer— bulb, stem, and capillary bulb—is exposed to the temperature being measured... 

How did Sir Thomas Allbutt reduce the size of the clinical thermometer from 30 cm to 15 cm and reduce the response time from 20 min to 5 min ... 

Air and clinical thermometers (Santorio Santorio) Santorio develops a small glass bulb that can be placed in a person s mouth, with a long, thin neck that is placed in a beaker of water. The water rises or fells as the person s temperature changes. 

The rectal temperatures are measured by means of a tested clinical thermometer or other suitable instrument of equal precision inserting to a depth uniform for each rabbit of 6 to 9 cm (7-5 cm). If the instrument is left in position for the duration of the test the rabbit may be restrained only with loosely fitting neck stocks so designed to allow the rabbit to sit normally. Temperatures are recorded at regular intervals at not more than thirty minutes commencing at least ninety minutes before the injection and continuing for three hours after the injection. The mean initial temperature, the mean of the temperatures recorded in the forty minutes prior to injection, is determined for each rabbit and the difference between this and the maximum temperature reached is taken to be its... 

Mercury thermometers, both for laboratory and clinical use, have been replaced by digital ones. 

The first clinical IRET used thermopile sensors to achieve non-contact temperature measurement in the ear. In 1991 a tympanic thermometer for home use was first introduced to the consumer market (Thermoscan HM 1). It utilized a pyroelectric sensor which requires the use of a suitable mechanical shutter or chopper mechanism, since it is only sensitive to temperature changes [3]. The main advantage of the pyroelectric sensor unit was its lower cost. However, prices for thermo-... 

J. Fraden, The development ofThermo-scan instant thermometer , Clinical Paediatrics, Supplement 1991, 18-22... 

THERMOMETER CLINICAL HUMAN ORAL DIGTAL LTWT 300 HOUR USE PLASTIC 6515013737292 EA 9.50 ... 

Z. Y. Zhang, K. T. V. Grattan, and A. W. Palmer, CnLiSAF fluorescence lifetime based fibre optic thermometer and its applications in clinical RF heat treatment, Int. Conf. on Biomedical Optics 93, Los Angeles, Jan. 1993, SPIE Proc. 1885, 300-305 (1993). 

Occupational exposure to inorganic mercury has been investigated in chloralkali plants, mercury mines, thermometer factories, refineries, and in dental clinics. High mercury levels have been reported for all these occupational exposure situations, although levels vary according to work environment conditions. 

Gallium is used as a fixed thermometric standard to calibrate thermistor probes of electronic thermometers used in clinical chemistry and experimental laboratory analyses (Scansetti 1992). This standard is appropriate because (i) the melting point of gallium (29.78 °C) falls within the region of critical importance to laboratory biological determinations (25-37°C) and (ii) the melt can be maintained accurately and constantly for several hours (Mangum 1977). 

FIGURE 169. These thermometers (see text) are found in the 1735 English edition of Herman Boerhaave s Elements of Chemistry. Boerhaave was not a distinguished chemist who made primary discoveries but rather a distinguished teacher of chemistry and medicine who helped introduce clinical teaching into medical school curricula. 

Examples include insulin syringes, blood pressure gauges, most diagnostic reagents, adult incontinent products, electric heating pads, clinical electronic thermometers, powered wheel chairs, infusion pumps, and surgical drapes. 

At this point, it seems that four courses of action are warranted for protection of human health and sensitive natural resources. First, toxic mercurials in agriculture and industry should be replaced with less toxic substitutes. In Sweden, for example, clinical mercury thermometers have been prohibited since January 1,1992, for import, manufacture, and sales. Since January 1993, the same prohibition was applied to other measuring instruments and electrical components containing mercury. Since 2000, Sweden has prohibited mercury in all processes and products, including thermometers and sphygmomanometers, and replaced them with available substitutes. 

An exception was items provided by vertical programmes via the DMO, such as test kits for HIV, malaria and pregnancy. These were generally available but had to be collected from the district centre - a challenge for rural dispensaries with no petty cash and no means of transport. Staff paid for their own transport if no lifts could be found one remarked, this is not correct. Medical equipment was the most problematic item even if you order them, you do not get them, so we do not order them...we ask donors to help. One clinical officer displayed thermometers obtained from a Dutch personal donor, a blood pressure machine sent to him hy a friend in the United States and a stethoscope he had bought himself individual networks of local rural sourcing were thus quite globalized. 

Cardwell, for example, comments (p.2) "Unfortunately there was for a long time doubt about what it (the thermometer) actually measured. As a clinical instrument it certainly reduced the subjective element in the diagnosis of fevers, but beyond this the exact significance of its reading was uncertain and interpretation of them depended on the observer s philosophy of nature."... 

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