Ch6 Patient Care in Imaging Technology - Vital Signs and Oxygen Administration

Objectives

Define vital signs and explain when assessment should be done.
List normal ranges for temperature, pulse, respiration, and blood pressure in children, adults, males, and females.
Identify sites and methods for measuring body temperature.
Identify common oxygen administration equipment and potential hazards.
Describe necessary equipment in radiographic imaging departments for monitoring blood pressure and administering oxygen.
List precautions for oxygen administration.
Accurately monitor pulse rate, respiration, and blood pressure.

Key Terms

Bradycardia: Slow heart rate (less than 60 bpm).
Chronic Obstructive Pulmonary Disease (COPD): Lung disease with diminished inspiratory and expiratory capacity.
Cyanosis: Bluish tone to lips and fingertips due to insufficient oxygen in the blood.
Diastolic: Blood pressure during ventricular relaxation (lowest reading).
Dyspnea: Difficult breathing due to insufficient airflow.
Hypercapnia: Carbon dioxide retention in arterial blood.
Hypothalamus: Brain region controlling body temperature.
Hypoxemia: Low oxygen levels in the blood.
Korotkoff Sounds: Extraneous sounds during blood pressure measurement (tapping, knocking, or swishing).
Sphygmomanometer: Blood pressure cuff.
Systolic: Blood pressure during ventricular contraction (highest reading).
Tachycardia: Fast heart rate (more than 100 bpm).
Tympanic: Relating to the tympanum or eardrum.
Vital Signs: Blood pressure, temperature, pulse, and respiration.
Volatile: Easily vaporized, unstable, or explosive.

Importance of Monitoring Vital Signs

Radiology nurses may handle routine monitoring in large facilities.
All technologists must understand how to monitor and record vital signs.
Recording vital signs is crucial for patient care.
Technologists need basic knowledge of oxygen cannulas and tanks.
Oxygen is potentially toxic and volatile, requiring precautions.
Physician's order not required for vital sign measurement.
Radiographer should take vital signs for invasive procedures, before/after medication, sudden changes in condition, or nonspecific symptoms of distress.

Measuring Vital Signs

Vital signs include body temperature, pulse, and respiration.
Blood pressure is often measured with vital signs.
Technologists must know how to measure vital signs in emergencies.
Establish baseline vital signs for comparison.
Changes in vital signs can indicate problems.
Assess patient's overall condition (skin color/temperature, consciousness, anxiety, communication ability).
Ensure functioning sphygmomanometer, stethoscope, and oxygen equipment are available in each imaging room.

Body Temperature

Physiologic balance between heat production and heat loss.
Must remain stable for efficient cellular and enzymatic activity.
Fluctuations of even 2° to 3° C can affect body's physiology.
Controlled by the hypothalamus (body's thermostat).
Metabolic activity produces body heat.
Influenced by environment, time of day, age, weight, hormone levels, emotions, exercise, digestion, disease, and injury.
Cellular functions and cardiopulmonary demands change with temperature variations.
Fever (pyrexia) indicates a disturbance in heat-regulating centers.
Fever symptoms: increased pulse and respiratory rate, discomfort, flushed skin, chills, loss of appetite.
Prolonged high fevers can damage the central nervous system (CNS).
Normal variation of $0.5$ ° to $1$ ° C above or below average is within normal limits.
Average body temperatures vary for infants and children (see Display 6-1).

Normal Vital Sign Ranges (Display 6-1)

Temperature
- Adult: $97.8$ ° to $99$ ° F
- Child (5-13 years): $97.8$ ° to $98.6$ ° F
- Infant (3 months-3 years): $99$ ° to $99.7$ ° F
Pulse
- Adult: $60$ to $90$ beats per minute
- Child (4-10 years): $90$ to $100$ beats per minute
- Infant: $120$ beats per minute
Respiration
- Adult: $15$ to $20$ breaths per minute
- Infant: $30$ to $60$ breaths per minute
Blood Pressure
- Adult: $90$ to $120$ systolic over $50$ to $70$ diastolic
- Adolescents: $85$ to $130$ systolic over $45$ to $85$ diastolic
Hypothermia: Body temperature below normal limits, potentially indicating a pathologic process; can be medically induced.
Survival is rare with body temperatures between $105.8$ ° F ( $41$ ° C) and $111.2$ ° F ( $44$ ° C) or below $93.2$ ° F ( $34$ ° C).

Measuring Body Temperature

Site selection depends on patient's age, mental state, and ability to cooperate.
Specify the site used when reporting the reading.
- Oral: 98.6 O
- Tympanic: 97.6 T
- Axillary: 97.6 Ax
- Rectal: 99.6 R
Use medically aseptic technique.

Oral Temperature

Taken by mouth under the tongue.
Average temperature is $98.6$ °F ( $37$ °C).
Use an electronic thermometer with a probe.
Ask if the patient has had anything hot or cold to eat or drink recently.

Tympanic Temperature

Uses a tympanic membrane thermometer (aural thermometer).
Measures temperature of blood vessels in the tympanic membrane.
Provides a reading close to the core body temperature.
Fast and easy method.

Axillary Temperature

Safest method (noninvasive).
Useful for infants.
Can be unreliable due to time and precision needed.
Use an electronic or disposable thermometer.
Average axillary temperature is $97.6$ ° to $98$ ° F ( $36.4$ ° to $36.7$ ° C).

Rectal Temperature

Taken at the anal opening to the rectum.
Average rectal temperature is $99.6$ ° F ( $37.5$ ° C).
Most reliable measurement of body temperature.
Close proximity to pelvic viscera.
Do not measure rectally if the patient is restless or has rectal pathology.
Use a thermometer with a blunt tip; never use an oral thermometer for rectal temperature.
Probe covers are often colored red for rectal temperature.

Other Instruments to Measure Body Temperature

Temperature-sensitive patches can be placed on the abdomen or forehead of infants or children.
Forehead and back of the ear scanning thermometers.
Unbreakable, disposable, single-use thermometers for unreliable patients.

Procedure: Tympanic Temperature

Place a clean sheath or cone on the probe.
Insert the probe into the external auditory canal and hold it firmly in place until the temperature registers automatically.
Remove the probe and read the indicator.
Remove the probe’s cover and dispose of it correctly.
Remove any gloves and wash hands.
Record the reading.
Immediately report any abnormal temperature to the radiologist in charge of the procedure.

Procedure: Axillary Temperature

Obtain the instrument to be used.
After putting on clean gloves, dry the armpit with a paper towel or dry washcloth.
Place the thermometer into the center of the armpit.
Place the patient’s arm down tightly over the thermometer with the arm crossed over the chest.
Gently hold the arm of a child or a restless adult in place until the thermometer has registered, usually about 1 minute.
Remove the thermometer and read the temperature.
Record the reading and dispose of the thermometer as appropriate.

Pulse

Blood is pumped in a pulsating manner into the arteries.
Pulse can be felt where arteries are superficial.
Easily detected areas:
- Apical: apex of the heart (stethoscope).
- Radial: radial artery at the wrists at the base of the thumb.
- Carotid: carotid artery at the front of the neck.
- Femoral: femoral artery in the groin.
- Popliteal: posterior surface of the knee.
- Temporal: temporal artery in front of the ear.
- Dorsalis pedis (pedal): top of the feet in line with the groove between the extensor tendons of the great and the second toe (may be congenitally absent).
- Posterior tibial: inner side of the ankles.
- Brachial: the groove between the biceps and the triceps muscles above the elbow at the antecubital fossa.
Pulse rate is usually the same as the heart rate.
Rapid pulse with low blood pressure indicates blood loss.
Normal average pulse rate:
- Adult: $60$ to $90$ bpm.
- Infant: $120$ bpm.
- Child (4-10 years): $90$ to $100$ bpm.
Refer to Display 6-1 for normal values for each group of patients.

Assessment of the Pulse

Pulse rate assesses cardiovascular function.
Tachycardia: > $100$ bpm.
Bradycardia: < $60$ bpm.
Assess before invasive procedures to establish a baseline.
Radial pulse is usually the most accessible for adults.
Count for one full minute.
If there is any irregularity of the radial pulse rate, take the apical pulse.
Apical pulse is monitored when the radial pulse is inaccessible.
Apical pulse is the most accurate for infants and children.
Femoral, popliteal, and pedal pulses are assessed bilaterally if peripheral blood flow is to be assessed.
Report the strength and regularity of the beat.
Normal rhythm is regular with equal time intervals between beats.
Weak or thready pulse: even slight finger pressure causes it to disappear.
Irregular, rapid, slow, or weak pulse should be immediately reported to the physician.
Changes in pulse rate during a procedure must also be reported.
Equipment: watch with a second hand, pad and pencil, stethoscope (for apical pulse).
Femoral, popliteal, and pedal pulses are palpated and assessed as present and strong, weak, regular, or irregular.
Mark the areas on the body with a marking pen where the pedal and popliteal pulses are palpated so that they may be rechecked as necessary.
Use "P" for pulse and "AP" for apical pulse (e.g., P 80).
Important note: Record any abnormalities and immediately report these to the patient’s physician.

Respiration

Function: exchange oxygen and carbon dioxide.
Oxygen taken into lungs during inspiration.
Oxygen transported to body tissues by arterial blood.
Deoxygenated blood returns to the heart through the venous system.
Carbon dioxide deposited in alveoli and exhaled during expiration.
Average respiration rate:
- Adult: $15$ to $20$ breaths per minute.
- Infant: $30$ to $60$ breaths per minute.
Fewer than $10$ breaths per minute may result in cyanosis, apprehension, restlessness, and altered consciousness.
*Normal respirations are quiet, effortless, and uniform.
*Medication, illness, exercise, or age may increase or decrease respirations
Dyspnea: patients are using more than the normal effort to breathe, they can be described as dyspneic or as having dyspnea.

Assessing Pulses

After completing the necessary handwashing, place the index finger and middle finger flat over the artery chosen for assessment.
Do not press too hard or the artery will be compressed and no beat will be felt. Do not use the thumb when counting the pulse rate because it too has a pulse that may be mistaken for the patient’s pulse.

Assessing Respiration

Establish a baseline respiratory rate.
Rate increases with exercise or emotion.
Quicker in newborns and infants.
Observe rate, depth, quality, and pattern.
Use "R" for respiration (e.g., R 20).
Report abnormalities (e.g., R 28, shallow and labored).

Procedure: Apical Pulse

Clean the earpieces and the bladder of the stethoscope with alcohol wipes and then wash hands.
Place the patient in a semi-Fowler or supine position.
Drape the patient so that the lower chest area is exposed.
Place the bladder of the stethoscope at the fifth intercostal space $5$ cm from the left sternal margin.
If the beat cannot be heard, move the stethoscope slightly in every direction until it can be heard.
Count the beats for 1 minute and assess for regular rate and rhythm.
Remove the stethoscope and cover the patient.
Clean the earpieces and bladder again with alcohol.
After completing a 30-second hand wash, record the pulse rate (i.e., AP 88) and report any irregularities.

Procedure: Assessing Respiration

Keep the patient in a seated or supine position.
The patient should be in a quiet state and be unaware that the breathing pattern is being observed.
The most convenient time to count respirations is immediately after the pulse count.
Observe the chest wall for symmetry of movement.
Important note: Patients who are aware of respiration assessment may alter their normal pattern of breathing.

Blood Pressure

Pressure is the product of flow and resistance.
Blood pressure is determined by:
- Peripheral resistance.
- Pumping action of the heart.
- Blood volume.
- Blood viscosity.
- Elasticity of vessel walls.
Decreased blood volume leads to decreased blood pressure because of diminished fluid in the arteries. Fluid or blood replacement reverses the problem.
Increased red blood cells results in increased blood viscosity which increases the blood pressure.
Arteries are normally elastic; however, age or buildup of atherosclerotic plaque reduces flexibility of the arteries and increases blood pressure.
Blood pressure varies with age, gender, physical development, body position, time of day, and health status.
Increases with age.
Usually lower in the morning.
Increases after a large intake of food.
Emotions and activity increase systolic blood pressure.
Men usually have higher blood pressure.
Infants generally have higher blood pressure than adults, and adolescents have the lowest overall blood pressure.
Instrument: sphygmomanometer.
Readings in millimeters of mercury (mm Hg): systolic and diastolic pressure.
Systolic: highest point during ventricular contraction.
Diastolic: lowest point during ventricular relaxation.
Normal blood pressure (National Heart, Lung, and Blood Institute):
- Below $120$ mm Hg systolic and $80$ mm Hg diastolic.
- Adolescents: $85$ to $130$ mm Hg systolic and $45$ to $85$ mm Hg diastolic.
- Prehypertension: $120$ to $139$ mm Hg / $80$ to $89$ mm Hg.
Pulse pressure: difference between systolic and diastolic, indicating stroke volume.
Pulse pressure decreases when a patient is in a state of hypovolemic shock.
Hypertensive: systolic > $140$ mm Hg or diastolic > $90$ mm Hg.
Hypotensive: systolic < $90$ mm Hg.

Equipment Needed to Measure Blood Pressure

Mercury or aneroid manometer.
Cloth cuff (various sizes).
Inflatable bladder.
Pressure manometer.
Thumbscrew valve.
Pressure bulb.
Rubber tubing.
Stethoscope (bladder or bell).
Automated vital sign monitor (for special procedures).

Measuring Blood Pressure

Patient seated with supported arm or supine.
Quiet room.
No clothing between cuff and skin.
Brachial artery of the left arm.
Clean stethoscope with alcohol.
When the diastolic pressure is heard, there may be a change in intensity of the sound before the sound is completely muffled. Then both readings must be recorded.
Korotkoff sounds: extraneous sounds (tapping, knocking, or swishing).

Procedure: Measuring Blood Pressure

Roll up the patient’s sleeve, if necessary. The brachial artery must be free of clothing.
Place the deflated sphygmomanometer cuff evenly around the patient’s upper arm above the elbow; secure it so that it will not work loose. Make sure that the cuff is facing the correct direction and that the arrow indicating the artery is placed appropriately.
Place the gauge of the sphygmomanometer on a flat surface or attach it to the top edge of the cuff so that it can be easily read.
Place the bladder or bell of the stethoscope over the brachial artery. This artery is located at the center of the anterior elbow and may be identified by feeling its pulsations. Place the instrument flat against the brachial artery. Do not allow the stethoscope or the tubing to touch the patient’s clothing because it will create sounds that may confuse the reading.
Next tighten the thumbscrew of the pressure bulb, and pump the bulb until the indicator or mercury reaches $180$ mm Hg or until the pulse beat is no longer heard.
Open the valve by slowly loosening the thumbscrew. Allow the indicator to fall at a moderate pace and listen for the first audible pulse beat. Listen carefully for the pulse beat to begin and take the reading on the gauge where it is first heard. This first reading is the systolic pressure.
Continue to listen to the pulsations until they become soft or the sound changes from loud to very soft or is inaudible. Note where the sound changes or is no longer heard. This is the diastolic reading.
Blood pressure measurement for infants and small children is a more complex procedure and requires a smaller sphygmomanometer cuff and less pressure exerted upon inflation.

Oxygen Therapy

Essential for survival; brain cannot function without it for more than 4-5 minutes.
Cannot be stored in the body; requires constant external supply.
Technologist must ensure oxygen equipment is available and functioning.
Technologist assists with oxygen administration in emergencies.
Oxygen and carbon dioxide are carried to and from the various body systems in the blood.
*CO2 diffuses into the plasma of systemic capillary blood, but the major part enters the red blood cells.
*Excess carbon dioxide results in changes in blood pH which is prevented by bicarbonate buffer.
*Arterial Blood Gases normal values:
pH: $7.35$ to $7.45$
PaCO2: $32$ to $45$ mm Hg
PaO2: $80$ to $100$ mm Hg
HCO3: $20$ to $26$ mEq/L
SaO2: $97$ %
Hypoxemia: inadequate oxygen in arterial blood.
Hypercapnia: carbon dioxide retention in arterial blood.

Pulse Oximetry

Monitors oxygen saturation of hemoglobin (SaO2).
Fast, noninvasive.
Sensor attached to fingertip or earlobe.
Normal SaO2 values: $95$ % to $100$ %.
Values less than $85$ % indicate inadequate oxygen to tissues.

Hazards of Oxygen Administration

Oxygen is a medication prescribed by a physician.
Excessive oxygen can be toxic to the lungs and CNS or may depress ventilation.
Mild oxygen toxicity may produce reversible tracheobronchitis.
Severe oxygen toxicity may cause irreversible parenchymal lung injury.
Administer the lowest possible amount of oxygen.
Special care for COPD patients; excessive oxygen may depress the respiratory drive.
*Patients with a chronic lung disease have chemoreceptors that no longer respond to the stimulus of CO2 to breathe, as occurs in a healthy person
Oxygen delivery equipment can be a source of infection.
Oxygen supports combustion; prevent sparks or flames.

Oxygen Delivery Systems

Administered artificially when patients cannot obtain adequate amounts from the atmosphere.
Humidified at high flow rates to prevent drying of mucous membranes.
Piped into patient rooms, postanesthesia areas, emergency suites, and the diagnostic imaging department.
Compressed in tanks of varying sizes if wall outlets are unavailable.
Twenty-one percent of the air we breathe normally is composed of oxygen.
Physician determines amount of oxygen and delivery device.
Flow rate measured in liters per minute (LPM).

Nasal Cannula

Disposable plastic device with two hollow prongs.
Delivers oxygen into the nostrils.
Most common delivery system.
Comfortable and convenient.
$21$ % to $60$ % oxygen concentration.
$1$ to $4$ LPM for adults.
$1/4$ to $1/2$ LPM for children.
Must be kept in place in both nostrils.

Nasal Catheter

French-tipped catheter inserted into one nostril to the oral pharynx.
Delivers moderate-to-high oxygen concentration.
$1$ to $5$ LPM flow rate.
Potential hazards: gastric distention, dry mucous membranes.

Face Mask

Used for short periods.
Placed over the nose and mouth.
Uncomfortable for long periods.
$30$ % to $50$ % oxygen concentration.
Run at no less than $5$ LPM to flush out CO2.

Other Face Masks

Nonrebreathing mask: may supply $100$ % oxygen; has a reservoir bag and a valve.
Partial rebreathing mask: delivers $60$ % to $90$ % oxygen; no valve between mask and bag.
Venturi mask: limits oxygen to $24$ % to $50$ % by mixing room air.
Aerosol mask: provides $60$ % to $80$ % oxygen mixed with water particles.

Other Oxygen Delivery Systems

Transtracheal delivery system: catheter inserted into the trachea for long-term continuous oxygen therapy.
Mechanical ventilators (respirators): control inspiration and expiration and FiO2 for patients with acute respiratory failure.

Home Oxygen Delivery Systems

Compressed gas in tanks.
Liquid oxygen: lightweight, portable, expensive (evaporates quickly).
Oxygen concentrator: electric machine that removes nitrogen, water vapor, and hydrocarbons, delivering oxygen at $90$ %.

Oxygen Delivery Equipment for the Imaging Department

Oxygen source (piped-in or tank; check daily).
Sterile nasal cannula or simple face mask (disposable).
Connecting tubing and adapter.
Humidifier (if indicated).
Flowmeter.
“No-smoking” sign.

Radiographic Examinations of the Chest

Detect pathological conditions that produce opacities with radiographic techniques.
Posterior/anterior and lateral radiographic images are frequently ordered to diagnose pulmonary pathology and determine placement of endotracheal tubes and hemodynamic devices.
Images may be taken at bedside.
Critical thinking and problem-solving skills are needed to obtain a diagnostically acceptable image.
Assess oxygen delivery and monitoring equipment and tubing placement before exposure to prevent repeating the exposure.

Cultural Considerations

Be mindful that certain cultures do not touch others even to determine heart rate, respirations, and pulse.
Provide a complete explanation and reassurance.

Summary

Body temperature balance between heat produced and lost.
Fever indicates disturbance in heat-regulating centers.
Temperature measured by oral, tympanic, rectal, and axillary methods.
Normal adult temperature:
- $97.6$ ° F axillary, $98.6$ ° F oral, $99.6$ ° F rectal
Pulse reflects heartbeat.
Measured at radial, temporal, carotid, femoral, apical, dorsalis pedis, and posterior tibial arteries.
Normal adult pulse rate is $60$ to $90$ bpm.
Respiration exchanges oxygen and carbon dioxide.
Normal adult rate is $15$ to $20$ breaths per minute.
Blood pressure is measured with a sphygmomanometer and stethoscope.
Measured at the brachial artery of the left arm.
Systolic and diastolic readings.
Influenced by age, exercise, medication, disease, and time of day.
Life cannot continue without oxygen
Oxygen cannot be stored in the human body
Pure oxygen is a hazardous substance to be used only when prescribed by a physician
It supports combustion, so all health care workers need to take precautions when it is in use
Radiographic exposures should not be made without adequate care being taken when oxygen is in use
Common delivery systems: nasal cannulas, catheters, face masks, nonrebreather masks, partial rebreather masks, rebreather masks, Venturi masks, aerosol masks, and ventilators.
Transtracheal delivery and mechanical ventilators for long-term or acute respiratory failure.
Nasal cannula most common; nasal catheter least common.
Radiographer may assist with oxygen administration or monitor vital signs in emergencies.