Describe how normal body temperature is maintained and explain how the nurse can ensure accuracy when measuring this vital sign
Every person creates heat in their bodies through the production of Adenosine triphosphate (also known as ATP or energy) which happens within the cells in the mitochondrion, this is also referred to as the metabolism and heat is the by product of the process in producing ATP which is called respiration (Waugh & Grant 2006). A person has two types of temperatures, a core temperature and a peripheral temperature. This essay will be looking at the differences in core and peripheral body temperatures, what a normal body temperature is, the role of homeostasis in the maintenance of body temperature, the role of the hypothalamus in body temperature, the ways in which a temperature can be measured, what physical and behavioural factors actually affect the body’s temperature and how nurses can use this understanding to certify accuracy.
Knowledge about the differences with the peripheral and core body temperatures are vital in the role of the nurse as this knowledge will allow the nurse to know if the temperature reading which s/he receives from a patient is accurate to that of the patient’s actual body temperature. The peripheral temperature relates to that temperature of the skin as well as there being the core temperature, which is the temperature of a person’s internal environment (Lees & Hilton 2004). Of the two temperatures, a core body temperature is far more important than that of a peripheral body temperature. The normal temperature range of a person’s core body temperature is that of 36-37°C (96.8-98.6°F) although this range changes from textbook to textbook (Lees & Hilton 2004). This temperature is optimum for a human body as if the temperature is too high or too low organs can go on to have irreversible damage (Waugh & Grant 2006). A temperature of 38-40°C (100.4-104°F) although high and potentially dangerous will not cause any long term damage. Someone with this temperature is thought to have pyrexia (Lees & Hilton 2004). However if their temperature rises about 43°C (109.4°F) there is little chance of the patient surviving. The same can be said for a patient with a temperature below 36°C (96.8°F). According to Lees & Hilton (2004) if a patient’s temperature falls between 28-35°C (82.4-95°F), they are said to be hypothermic but are likely to make a full recovery. But if that temperature were to drop below that of 25°C (77°F) then there is a very high probability of death occurring (Waugh & Grant 2006).
The human body is divided into external environment and internal environment. The internal environment is everything within the body and comprises of the cells and tissue formation to make the body’s structure and function the way it is. The external environment however is everything outside the body which will include the contents of a person’s stomach as the food and nutrients have not yet passed through into the body’s system. As the external environment is constantly changing, the internal environment would be disrupted accordingly. Instead the body has the function of homeostasis which keeps the body in check (Waugh & Grant 2006). Homeostasis maintains the body’s internal environment whilst the external environment changes. Homeostasis does not keep the internal environment to a specific condition; this is also constantly changing however it keeps it within a specified narrow range (Marieb 2009). Homeostasis is an important function within a person’s body. It works on an equilibrium balance effect which has a series of stages. These stages run in a chronological order whenever there’s an imbalance within the body’s system. As stated in Marieb’s (2009) work there is firstly the stimulus which is the actual imbalance within the body system such as an increase or decrease in body temperature; then there’s the receptor which will detect the increase or decrease in body temperature; once the receptor has detected the change it will send this message to the control centre which for temperature is the hypothalamus, depending on whether the temperature has increased or decreased, the hypothalamus will work accordingly which will send out a message to the body to either tell the blood vessels to vasoconstrict so that heat lost to the surface of the skin is decreased (if the body’s temperature is lower than usual) or it will send out a message to the blood vessels to vasodilate so that heat will be lost to the surface of the skin, it will also tell the body to produce sweat so that the heat can be evaporated away from the body. Once the body temperature has returned to ‘normal’, equilibrium has been reached and the hypothalamus will stop sending its message to the body (Marieb 2009).
A nurse will know what happens in a person’s body when the temperature is either increased or decreased accordingly but they will want to know why the patient’s body temperature has changed. There can be a number of different factors to a person’s body temperature changing. A person’s body temperature changes throughout the day, as in the early hours of the morning a person’s body temperature will decrease (Garret 2010). Also women’s temperature increases directly after ovulation (Waugh & Grant 2006). Factors affecting body temperature are put into two groups; physical factors and behavioural factors. Physical factors include things such as a person shivering, exercise, hormone secretion of thyroxine and epinephrine, sweating, vasoconstriction and vasodilatation of blood vessels and piloerection (the small hairs on your skin stand up to trap a layer of air around the body). Behavioural factors include heavy clothing (to induce heat) or light clothing (to reduce heat), movement or lack of movement, and seeking either a warm or cool environment (Mekjavic & Eiken 2006).
Knowing how a person’s temperature is regulated and also knowing the differences between a core body temperature and a peripheral body temperature, nurses use this information when they measure a patient’s temperature. Certain measurement areas are more accurate than others as these will give core body temperature readings, whereas other areas will give out peripheral body temperature readings. Lees & Hilton (2004) have mentioned some of the different areas that give you a temperature reading and these are as follows: aurally (also known as the tympanic membrane) this is site is most commonly used in finding a person’s temperature because it’s more efficient and less invasive; from the skin which is usually used in conjunction with the axillary (the arm pit) and these two sites have less reliable readings as they are readings for peripheral temperatures rather than the core temperature; rectally is a very accurate measurement of a person’s temperature however because this site is extremely invasive it is hardly used unless when an accurate core temperature is needed such as in cases of a patient with hypothermia or hyperthermia; lastly there’s the oral route of measuring temperature which used to be the most common site but there are difficulties with getting an accurate reading from the mouth. The difficulty with accuracy via the mouth for temperature readings is that the thermometer needs to be under the tongue in the pocket next to the frenulum. Although there are many different sites a nurse can use for finding a patient’s body temperature, once they have used one site, for example the tympanic membrane, for accuracy in comparing the temperatures in the future they should use the same site continuously (Lees & Hilton 2004).
A person’s body temperature is measured most commonly through the tympanic membrane as this is accurate and accessible, although if a patient has a specific condition such as hypothermia, for the most accurate of readings a rectal temperature would be the most appropriate. The temperature is maintained through the process of homeostasis which regulates the subtle changes within the body’s internal environment. The imbalance of the equilibrium is what sets off the chain reaction of events within the body’s system which involves the stimulus (thermo receptors), the control centre (the hypothalamus), and the effectors (vasoconstriction or vasodilatation of blood vessels). For a person’s temperature to reach its equilibrium again most efficiently then a nurse or the patient themselves can place themselves in an external environment that will help them such as if they are cold they should be put in a warm room or in warm clothing, whereas if the patient was cold they should be placed in a cool room or in cool loose fitting clothes.