temperature

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Maintaining body temperature how does the body do this

Heat productionBasal metabolic rateVoluntary movementShiveringHeat lossRadiationConductionConvection Evaporation – includes diaphoresis

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Maintaining body temperature

Heat production• Basal metabolic rate• Voluntary movement• Shivering

Heat loss • Radiation • Conduction• Convection• Evaporation – includes diaphoresis• Water loss via respiration.

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Body temperature

Core temperature is the temperature of the internal environment of the body. • This temperature is relatively constant.• It is regulated by the hypothalamus – (Gk – hypo – below, thalamos – chamber.) The hypothalamus activates, controls and integrates the peripheral autonomic nervous system, endocrine processes, and many somatic functions like temperature, sleep and appetite.

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Location of hypothalamus

www.vivo.colostate.edu/.../hypopit/anatomy.html

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Body temperature

Core temperature is the temperature of the internal environment of the bodyThis temperature is relatively constant.It is regulated by the hypothalamusThe surface temperature is the temperature at the surface of the bodyThe environmental temperature and blood circulation has a greater impact on this temperatureThe range of temperature is greater

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Body temperature regulation

1. Sensory receptors – primarily the skin.

2. Hypothalamus – controls core temp.

3. Effector system –

- prevents heat loss by –1. Shivering

2. Peripheral constriction

3. Release of epinephrine – increases BMR.

- Promotes heat loss by –4. Sweating

5. Peripheral vasodilation

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Factors affecting body temperature

Age – very young, elderlyExerciseHormonal level – ovulationCircadian rhythm – higher in the late afternoon, early eveningStressEnvironmentAlteration in body function – infection, dehydration

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Terms related to body temperature

Normothermia – 36.1 – 37.2Afebrile FeverFebrilePyrexiaHyperthermiaRigor hypothermia

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GradeLow grade fever

TemperatureNormal to 38

Possible causeInflammatory response to mild infection, allergy, disturbance of body tissue by trauma, surgery, malignancy or thrombosis

Moderate high grade temperature

38-40 C May be caused by wound, respiratory or UTI

Hyperpyrexia > = to 40 C May be caused by bacteraemia, damage to the hypothalamus ore high environmental temperatures

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Patterns of fever

Sustained a constant body temperature continuously above 38 that demonstrates little fluctuationIntermittent fever spikes interspersed with usual temperature levels. Temperature returns to acceptable levels at least once in 24 hours.Remittent fever spikes and falls without a return to normal temperature levelsRelapsing periods of febrile episodes interspersed with acceptable temperature values. Febrile episodes and periods of normothermia may be longer than 24 hours

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S&S of fever

ONSET• Increased HR• Increased RR• Shivering – why?• Pallor & cold skin – why?• Patient c/o feeling cold• ‘goose bumps’• Cessation of perspiration• Rise in temperature

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S&S of fever

PROGRESSION• Absence of shivering• Skin feels warm to touch – forehead, cheeks.• Increased P & RR• Increased thirst• Mild to severe degydration• Drowsy, restless + / - delirium (if very high)• Anorexia• Malaise, weakness, ‘aches & pains’

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S&S of fever

ABATEMENT• Skin flushing, feels hot• Sweating• Decreased shivering• Possible dehydration

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Fever

Flushing can occur on the face or over the entire body.

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Hyperthermia – 38-41C

Heatstroke Those at risk• The very young the very old• Cardiovascular disease, hypothyroidism,diabetes or

alcoholism• Medications (phenothiazine's, anticholinergic, diuretics,

amphetamines and beta –adrenergic receptor antagonist

• Those who exercise or work strenuously - athlete, construction workers and farmers

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Signs and symptoms

Giddiness, confusion, delirium, excess thirst,nausea, muscle cramps, visual disturbances and even incontinence.

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Hyperthermia - heatstroke

Victims of heatstroke do not sweat because of severe electrolyte loss and hypothalamic malfunctionsHeatstroke greater than 40.5 C produces tissue damage to the cells of all body organs. Vital signs may indicate temp greater than 41C , tachycardia, and hypotension.Temperatures above 41C can cause convulsions and a temperature of 43 C renders life unsustainable.Heat exhaustion occurs when profuse diaphoresis results in excess water and electrolyte loss

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hypothermia

Body temperature drops and mechanisms to increase heat production are ineffectiveCauses Environmental exposureMedication ( alter perception , cause heat loss through vasodilatation, inhibit heat generation eg panadol, alcohol)Metabolic conditions eg hypoglycemia and adrenal insufficiencyExposure of internal organs during surgery

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hypothermia

Core temperatureMild (33.1-36)Moderate (30.1 – 33)Severe (27 -30)Profound ( less than 27)To 35- shivering , loss of memory, depression and poor judgment34.3 – cardiac dysrythmias , loss of consciousness, unresponsive to pain

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hypothermia

Frostbite- when the body is exposed to subnormal temperatures the ice crystals that form inside the cell can result in permanent circulatory and tissue damage. The area is white , waxy and firm to the touch)

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Frostbite

Frostbite

www.project-himalaya.com nl.savetibet.org

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Conditions requiring frequent monitoring Patient’s condition affects their BMRPost operativelyCritically ill patientsPatients susceptible to infectionImmuno compromisedThose undergoing chemotherapy, radiation therapy or steroid therapyPatient has local or systemic infectionPatients receiving a blood transfusion

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Types of thermometers

Tympanic

Electronic

Digital

Disposable (not used in hospitals)

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Contraindications/ cautions for oral temperature

• Children younger than 5 years• Confused or combative patients• Those that cannot close their mouth fully (injury ,

surgery)• Unconscious patients or those prone to

convulsions• Mouth breathers• Mouth infection• Wait 15 minutes after patient smokes, drinks, eats• Place thermometer in the sublingual pocket• Leave insitu for 2 minutes with lips closed

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Digital oral thermometer

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guardian.co.uk

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Contradictions/ cautions for rectal temperature

Don’t use this route if patient has rectal or perineal injuries or surgeryA rectum full of soft faeces may cause an inaccurate reading (lower)This site is least used (because of its intrusive nature) but it is more accurate than the others though there is lag time with febrile states.Lubricate and insert (at least 4 cm) gently Don’t leave patient unattended and ensure that patient doesn’t moveLeave insitu for 2 minutes

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Cautions and /contraindications for tympanic temperature• Remove hearing aids• Don’t use the ear that the patient has been

lying on • Most commonly used site• Wax buildup may lower temperature• Otitis media may increase temperature• The tip of the thermometer has to fit snugly

and point to the tympanic membrane to read accurately

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Contraindications and cautions for axilla temperature

Area must be dry and cleanThere must be contact with both skin surfacesThe thermometer may have to be helped in position The least accurate site (surface temperature)The thermometer must be insitu for 5 minutes

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