Vital Signs: Unlocking the Mysteries of the Client’s Health Status Vital Signs Provide One of the Most Important Keys to the Client’s Baseline Status and Response to Medical or Nursing Treatment Vital signs generally include temperature, pulse, resp, and blood pressure. Oxygen saturation may be included based on hospital or unit policy. Vital signs provide a efficient method for monitoring a client’s condition or identifying problem areas or assessing a client’s response to treatment.

Guidelines for Taking Vital Signs Collection of vital signs during the routine assessment provides a baseline for future assessments. The nurse is responsible for vital signs interpretation, but may delegate activity to an unlicensed personnel. Equipment must be functional and appropriate for age. Important to know the usual values for the individual client. Trends are most important. Important to recognize the effects of medical history and current medications. Minimize environmental factors that affect the vital signs. The nurse should demonstrate vital signs in an organized, systemic approach with a calm and caring manner. Medications may be administered based on vital sign values. Physician or other responsible care providers should be notified of abnormalities.

Physiology of Body Temperature Body temperature is the difference between heat produced by internal processes and heat lost through the external environment. Temperature control mechanisms keep the the body’s core temperature relatively constant. Acceptable range is 36.5-37.5 degrees C (97.6 – 99.6 degrees F). Various sites may be used but the pulmonary artery is the most accurate.

Thermoregulation Hypothalamus – “thermostat” of the body, is located between the cerebral hemispheres. Anterior – reduces body temperature. Posterior – increases body temperature. Basal metabolic rate (BMR) Heat loss – radiation, conduction, convection, evaporation, diaphoresis Anterior hypothalamus senses the elevated temp and triggers heat loss mechanisms ( sweating, vasodilation of blood vessels, inhibition of heat production). Posterior hypothalamus senses a low temp and triggers heat conservation mechanisms, which include vasoconstriction and compensatory heat production (shivering). Heat is produced in the body by metabolism, which is the chemical reaction in all body cells. Food is the primary source of fuel of this chemical reaction. The amount of energy used for metabolism is the metabolic rate. Heat is produced as a by-product of metabolism. Activities that increase chemical reactions increase the metabolic rate. BMR – the amount of heat produced by the body at absolute rest. The average BMR depends of body surface area. Thyroid hormones have a significant effect on BMR, increased production of hormones increases the rate of chemical reactions and increases BMR. Decreased thyroid levels decreases BMR. Due to male sex hormones, testosterone, men have a higher BMR than women. Voluntary movements increase BMR. Shivering can increase heat production by 4-5 > normal. Heat loss – Radiation – transfer of heat from the surface of one object to the surface of another without direct contact. Example – removing clothes, change of position. Conduction – transfer of heat from one object to another with direct contact. Example – applying ice pack or bathing in cool water. Convection – transfer of heat by air movement. Example – air movements from electric fan. Heat loss increased with moist skin. Evaporation – trans of heat energy when a liquid is changed to a gas. During evaporation, approx. 0.6 of a calorie of heat is loss for each gram of water that evaporates. Adults lose 600-900 ml of water thru evaporation from the skin and lungs per day. As sweat evaporates we lose heat. Diaphoresis – visible perspiration primarily on forehead and upper thorax. Diaphoresis is an example of evaporation. Insulation, vasoconstriction, and temperature sensation play role in skin temperature. Body fat keeps heat in. If person is too hot the hypothalamus sends message to blood vessels to dilate and more heat is lost. Cooler temp causes increased constriction and heat is conserved. Behavioral control – depends on degree of temp extreme, person’s ability to sense feelings, thought processes, ability to move. Other factors to affect temp include: age, exercise, hormone level, circadian rhythm, stress, environment. Skin plays an important role in temperature regulation. Behavioral control affects temperature.

Temperature Alterations Hyperpyrexia (fever) – heat loss is unable to keep pace with excess heat production Pyrogens – bacteria and viruses cause a rise in body temperature. Febrile – state of elevated body temperature Afebrile – absence of fever Fever is an important defense mechanism. Mild temp (< 102.2 degrees F) can enhance the immune system. FUO – fever of unknown origin Hyperthermia – elevated body temperature Malignant hyperthermia – hereditary condition of uncontrolled heat production, occurs in susceptible persons that receive certain anesthetic drugs. Hypothermia – decreased body temperature, classified by core temperature measurements. Make sure to review definitions of heatstroke and heat exhaustion. Hypothermia Mild 91.5 to 96.8 Moderate 86.1 – 91.4 Severe 80.6 – 86.0 Profound <80.6

Temperature Assessment Due to the tympanic membrane sharing the same arterial supply as the hypothalamus, it is considered a core temperature. Temperature varies among sites. Rectal is usually 1 degree higher than oral and axillary is usually 1 degree less than oral.

Thermometers Electronic Tympanic Glass Oral – slim or elongated Stubby can be used for all sites Red bulb – rectal only Electronic Blue – oral or axillary Red – rectal Tympanic Tympanic - do not use in infants < 2 mos. Do not use in people with excessive ear drainage or tympanic damage. Disposable paper or strips usually not very accurate.

Temperature Conversions F = (9/5 x C) + 32 104 F = (9/5 x 40 C) +32 C = (F-32) x 5/9 40 C = (104F –32) x 5/9 Memorize these formulas.

Converting Fahrenheit to Centigrade

C = (F – 32) x 5/9 C = ( 101 – 32 ) x 5/9 C = 69 x 5/9 C = 38

C = (99.6F – 32) x 5/9 C = 67.6 x 5/9 C = 37.5

Convert Centigrade to Fahrenheit

F = (C x 9/5) + 32 F = (38C x 9/5) +32 F = 68.4 + 32 F = 100.4

Treating a Fever Tepid sponge bath Ice packs Antipyretics Hypothermia blanket Cooling fans Avoid the stimulation of shivering May give bath with alcohol in bathing water, but generally believed to promote too rapid cooling. Fever in children are usually related to viral origin. Freq run fever > 101.8 degrees. Dehydration and febrile seizures more common with infants > 6 mos and < 3 yrs of age. Seizures rarely occur after age 5. Important to stress liquids and oral intake. Elderly tend to run a lower temp. Important to know what is the normal temp. Temp of 100.4 may be within normal range, but in elderly may indicate fever. Cultures may be ordered. Usually give meds after the culture is drawn.

Pulse Palpable bounding of blood flow noted at various points of the body. Blood flows in a continuous circuit. Electrical impulses are initiated by the SA node and stimulated the heart muscle to contract. Stroke volume – amt of blood pumped from the heart with each contraction. Cardiac output – amt of blood ejected from the heart in 1 min. CO = SV x HR Normal CO = 4-6 liters/min Mechanical, neural, and chemical factors regulate the strength of contractions and stroke volume. Pulse increase can be affected by blood pressure and temp also. Factors affecting pulse: age, autonomic nervous system, medications.

Pulse Sites Temporal Carotid Radial Ulnar Brachial Apical Femoral Popliteal Dorsal pedis Posterior tibial Carotid most common in emergencies. Radial is most common for routine examination. Apical pulse provides a more accurate assessment of heart function.

Assessment of the Pulse Rate Apical S1 = lub S2 = dub Rhythm Strength (Quality) Equality Discuss parts of stethoscope. Bell is for low-pitched sounds. Diaphragm is for high-pitched sounds. Rate Tachycardia – hr >100bpm Bradycardia - < 60bpm Rhythm Dysrhythmia – irregular, early, late, or missed beat Pulse deficit – pulse wave is not transmitted to extremities. Requires two nurses, one assesses peripheral pulse while other assesses apical pulse and then compare rates. The difference between apical and radial rate is the pulse deficit. Strength – normal, weak, thready, bounding Equality – equal between extremities. Never palpate carotid bilaterally at the same time. May use Doppler if unable to palpate pulse.

Questions Which pulse point would allow you to best assess the circulation to the feet. A. temporal B. brachial C. posterior tibial D. pedis ulnus

An irregular rhythm requires a full minute of assessment. True or False?

Respirations Ventilation – movement of gases in and out of lungs Diffusion – movement of oxygen and CO between alveoli and RBC Perfusion – the distribution of RBC to and from pulmonary capillaries Discuss difference between respiration and ventilation. External respiration - taking in O2 and eliminating CO2. Internal respiration - exchange of these gases between the blood vessels and cells.

Physiological Control Inspiration is active Respiratory center of the brain controls respirations Normal rate 12-20/min (adult) and 40- 60/min (infants) Levels of CO2 help regulate ventilation - Increased CO2 leads to increased ventilation - In COPD patients low levels of O2 stimulate respirations Hypoxemia – low levels of arterial O2. High levels of O2 in COPD patients can lead to respiratory depression

Mechanics of Breathing Inspiration is active process initiated by impulses from phrenic nerve. Diaphragm contracts and chest wall moves out. Expiration is passive process. Diaphragm relaxes and chest wall returns to normal position. Tidal volume – amount of air inhaled and exhaled during a normal ventilation. Approx. 500 ml of air. Eupnea – normal rate and depth of ventilation.

Assessment of Respirations Rate – assess without client’s knowledge of action. Rhythm – Men and children tend to be diaphragmatic breathers. Women tend to use thoracic muscles more. Labored respirations require use of accessory muscles. Infants breathing more irregularly. Depth – deep, normal, or shallow.

Oxygen Saturation SaO2 = percent of hemoglobin that is bound with oxygen in the arteries. Normal SaO2 is 95-100%. Pulse oximeter is utilized to provide indirect measurement of oxygen saturation. Values obtained with pulse oximetry are less reliable if the SaO2 is <70%. May apply probe to finger or earlobe. Sole of foot may be used in infants.

Questions An infant is brought into the emergency by his mother with a fever for 2 days. You find the following respiration rate of 40 which is regular and unlabored. A. You notify the provider immediately B. You document the finding as R 40 C. You set the infant upright and apply oxygen.

Blood Pressure Definition – lateral force on the walls of the artery by the pulsing blood under pressure from the heart. Blood is forced from atria to ventricles to aorta. Systolic = peak of maximum pressure when ejection occurs. Diastolic = minimum pressure, the ventricles have relaxed and the blood remaining in the arteries is at the lowest pressure. Pulse pressure = difference between systolic and diastolic. Normally 30 – 50 mm Hg. Adult BP range systolic: <130 diastolic < 85

Physiology of Blood Pressure Cardiac Output – volume of blood ejected over 1 minute. CO = SV x HR Stroke Volume – amount of blood ejected from the heart with each contraction. Blood pressure is affected by cardiac output and peripheral vascular resistance. BP = CO x resistance Peripheral resistance, blood volume, viscosity, and elasticity all play a role in blood pressure. Cardiac output can be increased by increased heart rate, increased volume, increased contractility of the heart muscle. Peripheral vascular resistance – the resistance to blood flow determined by the tone of vascular musculature and diameter of blood vessels. The smaller the vessel, the greater the PVR to the flow. When PVR increases then blood pressure increases. Decreased PVR (vasodilation), leads to decreases blood pressure. Blood volume – Normal circulating volume is about 5 liters. If volume increases, then more pressure is exerted against the walls (overhydration). Hypovolemia causes decreased BP and decreased CO. Viscosity – Thickness of blood. Increased viscosity requires more pressure to push the blood thru the vessels. Hematocrit, % of RBC in the blood. Increased hematocrit would increase viscosity. Elasticity – Normally walls are elastic. In certain diseases, the walls lose their elasticity and are replaced by fibrous tissue that does not stretch. With reduced elasticity, there is increased pressure or resistance to blood flow. This leads to increased systolic blood pressure, esp in older adults.

Factors Affecting Blood Pressure Age Stress Race Medications Diurnal Variation Gender Age: Normal adult 120/80 with acceptable values< 130/< 85. Older adults have a higher systolic pressure d/t decreased vascular elasticity. Stress contributes to elevated Bp Race: Afro-Americans at higher risk for stroke and MI Medications: Antihypertensives, cardiac drugs, and narcotic analgesics. Diurnal Variation: Lowest in morning and gradually rises during day. Gender: Men higher than women until after menopause and women become higher.

Abnormalities in Blood Pressure Hypertension – (JNC7) the average of 2 or more properly measured, seated BP readings: SBP 140-159 or DBP 90-99, classified as stage 1 hypertension. HTN associated with family hx, cigarette smoking, obesity, heavy alcohol consumption, high Na intake, sedentary lifestyle, diabetes, age, and race. Hypotension – SBP < 90 mm Hg. Associated S/S are pallor, decreased UOP, increased HR, clamminess, confusion. Orthostatic hypotension – Decreased in BP with increase in HR and resp. Associated by volume depletion.

Questions This is the first time you have seen this 45 year old female. She has no prior medical history. Her blood pressure reading is 148/94. Does this support the diagnosis of hypertension? Why or why not?

She comes back in one week for a recheck of her blood pressure She comes back in one week for a recheck of her blood pressure. Her BP is 154/90. She is diagnosed with hypertension by the primary care provider. Which of the following could be affecting her BP? A. age B. weight 185, height 5’4” C. stress D. inadequate equipment

Pediatric Considerations Best results – count resp 1st, pulse 2nd, and temp last. If VS cannot be taken without disturbing the child, record the child’s behavior (crying). Other s/s of increased temp: flushed skin, increased resp and heart rates, malaise, and “glassy look” to eyes. Radial pulse in children > 2yrs. Infants < 2 yrs should use apical pulse. Count for 1 full min d/t irregularities. Respirations – infants require observation of abdominal movements d/t diaphragmatic breathing. Count for 1 full min. Read pages 242-250 in Whaley & Wong. Do not memorize cuff sizes. Tell the child “I want to see how strong your arm is” to check BP. Appropriate cuff size is very important!

Normal Pediatric Blood Pressure Systolic 1-7 years: Age in years + 90 8-18 yrs: (2 x age in years) + 83 Diastolic 1-5 yrs: 56 6-18 yrs: Age in years + 52