Maintaining body temperature how does the body do this • Heat production • Basal metabolic rate • Voluntary movement • Shivering • Heat loss • Radiation • Conduction • Convection • Evaporation – includes diaphoresis
Maintaining body temperature • Heat production • Basal metabolic rate • Voluntary movement • Shivering • Heat loss • Radiation • Conduction • Convection • Evaporation – includes diaphoresis • Water loss via respiration.
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.
Location of hypothalamus www.vivo.colostate.edu/.../hypopit/anatomy.html
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 • The surface temperature is the temperature at the surface of the body • The environmental temperature and blood circulation has a greater impact on this temperature • The range of temperature is greater
Body temperature regulation • Sensory receptors – primarily the skin. • Hypothalamus – controls core temp. • Effector system – • - prevents heat loss by – • Shivering • Peripheral constriction • Release of epinephrine – increases BMR. - Promotes heat loss by – • Sweating • Peripheral vasodilation
Factors affecting body temperature • Age – very young, elderly • Exercise • Hormonal level – ovulation • Circadian rhythm – higher in the late afternoon, early evening • Stress • Environment • Alteration in body function – infection, dehydration
Terms related to body temperature • Normothermia – 36.1 – 37.2 • Afebrile • Fever • Febrile • Pyrexia • Hyperthermia • Rigor • hypothermia
Patterns of fever • Sustained a constant body temperature continuously above 38 that demonstrates little fluctuation • Intermittent 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 levels • Relapsing periods of febrile episodes interspersed with acceptable temperature values. Febrile episodes and periods of normothermia may be longer than 24 hours
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
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’
S&S of fever • ABATEMENT • Skin flushing, feels hot • Sweating • Decreased shivering • Possible dehydration
Fever • Flushing can occur on the face or over the entire body.
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
Signs and symptoms • Giddiness, confusion, delirium, excess thirst,nausea, muscle cramps, visual disturbances and even incontinence.
Hyperthermia - heatstroke • Victims of heatstroke do not sweat because of severe electrolyte loss and hypothalamic malfunctions • Heatstroke 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
hypothermia • Body temperature drops and mechanisms to increase heat production are ineffective • Causes • Environmental exposure • Medication ( alter perception , cause heat loss through vasodilatation, inhibit heat generation eg panadol, alcohol) • Metabolic conditions eg hypoglycemia and adrenal insufficiency • Exposure of internal organs during surgery
hypothermia • Core temperature • Mild (33.1-36) • Moderate (30.1 – 33) • Severe (27 -30) • Profound ( less than 27) • To 35- shivering , loss of memory, depression and poor judgment • 34.3 – cardiac dysrythmias , loss of consciousness, unresponsive to pain
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)
Frostbite • Frostbite www.project-himalaya.com nl.savetibet.org
Conditions requiring frequent monitoring • Patient’s condition affects their BMR • Post operatively • Critically ill patients • Patients susceptible to infection • Immuno compromised • Those undergoing chemotherapy, radiation therapy or steroid therapy • Patient has local or systemic infection • Patients receiving a blood transfusion
Types of thermometers • Tympanic • Electronic • Digital • Disposable (not used in hospitals)
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
Digital oral thermometer guardian.co.uk
Contradictions/ cautions for rectal temperature • Don’t use this route if patient has rectal or perineal injuries or surgery • A 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 move • Leave insitu for 2 minutes
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
Contraindications and cautions for axilla temperature • Area must be dry and clean • There must be contact with both skin surfaces • The thermometer may have to be helped in position • The least accurate site (surface temperature) • The thermometer must be insitu for 5 minutes