temperature

TEMPERATURE

BY-Jai pratap singh

mbbs

• Normal human body temperature, also known as normothermia or euthermia, depends upon the place in the body at which the measurement is made, and the time of day and level of activity of the person.

• In healthy adults, body temperature fluctuates about 0.5 °C (0.9 °F) throughout the day, with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.

• The time of day and other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the nadir, is one of the primary markers for circadian rhythms. The body temperature also changes when a person is hungry, sleepy, or cold.

• Temperature control (thermoregulation) is part of a homeostatic mechanism that keeps the organism at optimum operating temperature, as it affects the rate of chemical reactions. In humans the average internal temperature is 37.0 °C (98.6 °F), though it varies among individuals. However, no person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's circadian rhythm. The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.

• In addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.9 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day.

Diurnal variation in body temperature, ranging from about 37.5 °C from 10 a.m. to 6 p.m., and falling to about 36.4 °C from 2 a.m. to 6 a.m.

• Taking a patient's temperature is an initial part of a full clinical examination. Sites used for measurement include:

• In the anus (rectal temperature)

In the mouth (oral temperature)

Under the arm (axillary temperature)

In the ear (tympanic temperature)

In the vagina (vaginal temperature)

On the skin of the forehead

Over the temporal artery

In the gut (by swallowing a small thermometer)

• The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows:

• Temperature in the anus (rectum/rectal), vagina, or in the ear (otic) is about 37.5 °C (99.5 °F)

• Temperature in the mouth (oral) is about 36.8 °C (98.2 °F)

• Temperature under the arm (axillary) is about 36.5 °C (97.7 °F)

HYPOTHERMIA

HYPOTHERMIA• Hypothermia is a potentially dangerous drop

in body temperature, usually caused by prolonged exposure to cold temperatures.

• Normal body temperature averages 98.6 degrees. With hypothermia, core temperature drops below 95 degrees. In severe hypothermia, core body temperature drops to 86 degrees or lower.

• HYPOTHYROIDISM IS OFTEN A CONTRIBUTORY FACTOR IN THE OLD AGE, WHILE ALCOHOL AND OTHER DRUGS(e.g. PHENOTHIAZINES) COMMONLY IMPEDE THE THERMOREGULATORY RESPONSE IN YOUNGER PEOPLE.

• MORE RARELY, HYPOTHERMIA IS SECONDARY TO GLUCOCORTICOIDS INSUFFICIENCY, STROKE, HEPATIC FAILURE OR HYPOGLYCAEMIA.

C/F

• MILD HYPOTHERMIA

COLD AND SHIVERING CONFUSION DEHYDRATION ATAXIA

• SEVERE HYPOTHERMIA

COLD AND NOT SHIVERING

DEPRESSED CONSCIOUS LEVEL

MUSCLE STIFFNESS BRADYCARDIA HYPOTENSION ECG: J WAVES DYSRHYTHMIA

INVESTIGATION

BLOOD GASES A FULL BLOOD COUNT ELECTROLYTES CHEST X-RAY ELECTROCARDIOGRAM (ECG)

MANAGEMENT

• CONTINUED HEAT LOSS IS PREVENTED BY SHELTERING THE PT. FROM THE COLD,REPLACING WET CLOTHING, COVERING THE HEAD AND INSULATING HIM/HER FROM THE GROUND.

• REWARMING RATES OF 1-2⁰C/HOUR ARE EFFECTIVE IN LEADING TO A GRADUAL AND SAFE RETURN TO PHYSIOLOGICAL NORMALITY.

• IN CASE OF SEVERE HYPOTHERMIA WITH CARDIO- REWARMING AT THE RATE GREATER THAN 2⁰C/HR• THIS IS BEST ACHIVED BY

CARDIOPULMONARY BYPASS OR EXTRACORPOREAL MEMBERANE OXYGENATION.

COLD INJURY

FREEZING COLD INJURY ( FROST

BITE)• THIS REPRESENT THE DIRECT FREEZING OF

THE BODY TISSUES AND USUALLY AFFECTS THE EXTREMITIES

THE FINGERSTOESEARSFACE

•RISK FACTORS

1)SMOKING2)PERIPHERAL VASCULAR

DISEASE3)DEHYDRATION4)ALCOHOL CONSUMPTION

• REWARMING SHOULD NOT OCCUR UNTIL IT CAN BE ACHIVED RAPIDLY IN A WARM BATH.

• GIVE ASPIRIN 300 mg & OXYGEN AS SOON AS POSSIBLE.

• FROST BITTEN EXTRIMITES SHOULD BE REWARMED IN WARM WATER AT 40-42⁰C, WITH ANTISEPTIC ADDED.

• VASODIALATORS SUCH AS PENTOXIFYLLINE IMPROVES TISSUE SURVIVAL.

• WOUND DEBRIDMENT MAY BE NECESSARY, AMPUTATION SHOULD BE DELAYED FOR 60-90 DAYS.

NON FREEZING COLD INJURY (TRENCH OR

IMMERSION FOOT)• RESULT FROM PROLONG EXPOSURE TO COLD, DAMP CONDITION.• THE LIMB (USUALLY THE FOOT)

APPEARS COLD,ISCHEAMIC AND NUMB, BUT THERE IS NO FREEZING OF THE TISSUE.

• ON REWARMING , THE LIMB APPEARS MOTTLED AND THEREAFTER BECOMES HYPERAEMIC, SWOOLEN AND PAINFUL.

• T/Ta) GRADUAL REWARMINGb) PAIN- AMITRIPTYLINE(50 mg)

CHILBLAINS• ARE TENDER, RED OR PURPLISH SKIN LESIONS

THAT OCCUR IN THE COLD AND WET.• OFTEN SEEN –HORSE RIDERSCYCLISTSWIMMERSWOMEN>MEN• SHORT LIVED, PAINFUL NOT USUALLY SERIOUS

HEAT RELATED ILLNESS

• WHEN GENERATION OF HEAT EXCEEDS THE BODY’S CAPACITY FOR HEAT LOSS, CORE TEMPERATURE RISES.

•D/DI. Heat illness( heat exhaution,heat stroke)II. Sepsis, include meningitisIII. MalariaIV. Drug overdoseV. Malignant hyperpyrexiaVI. Thyroid storm

HEAT CRAMP• Heat cramps are painful, brief muscle

cramps. Muscles may spasm or jerk involuntarily. Heat cramps can occur during exercise or work in a hot environment or begin a few hours later.

• Heat cramps usually involve muscles that are fatigued by heavy work such as calves, thighs, and shoulders.

•Causes of Heat Cramps• The exact cause of heat cramps is

unknown. They are probably related to electrolyte problems. • Electrolytes include various essential

minerals, such as sodium, potassium, calcium, and magnesium. They undergo chemical changes in tissues.

•Symptoms of Heat Cramps• Muscle spasms that are:• Painful• Involuntary• Brief• Intermittent• Usually self-limited (go away on their

own)

HEAT SYNCOPE

• SIMILAR TO A VASOVAGAL FAINT.• IS RELATED TO

PERIPHERAL VASODILATATION IN HOT WEATHER.

HEAT EXHAUSTION

• OCCURS WITH PROLONGED EXERTION IN HOT AND HUMID WEATHER, PROFUSE SWEATING AND INDEQUATE SALT AND WATER REPLACEMENT.

• ELEVATION IN CORE (Rectal)TEMP. TO BETWEEN 37-40⁰C

• BLOOD ANALYSES – EVIDENCE OF DEHYDRATION WITH MILD ELEVATION OF BLOOD UREA, SODIUM, HAEMATOCRIT.

T/T

HEAT STROKE• WHEN CORE BODY TEMPERATURE RISES ABOVE

40⁰C & IS A LIFE THREATENING CONDITION.• SYMPTOMS-HEADACHENAUSEAVOMITINGMUSCLE TREMORCONFUSIONAGGRESSION OR LOSS OF CONSCIOUSNESS

•COMPLICATION-HYPOVOLUMIC SHOCKLACTIC ACIDOSISDISSEMINATED INTRAVASCULAR

COAGULATIONRHABDOMYLOSISHEPATIC & RENAL FAILUREPULMONARY & CEREBRAL OEDEMA.

• THE PT. SHOULD BE RESUSCITATED WITH RAPID COOLING BY SPRAYING WITH WATER, FANNING AND ICE PACKS IN THE AXILLA AND GROINS.• COLD CRYSTALLOID I.V. FLUID IS

GIVEN BY SOLUTION CONTAINING POTASSSIUM SHOULD BE AVOIDED.

THANK YOU