Vital Signs (Encyclopedia of Nursing & Allied Health)

Definition

Simply stated, vital signs are "signs of life." Temperature, beat of the heart (pulse), respiratory rate, and blood pressure signal that a person is alive. All of these vital signs can be observed, measured, and monitored. This will enable the assessment of the level at which the individual is functioning. Normal ranges of measurements of vital signs change with a person's age and medical condition.

Purpose

To establish a baseline on admission to a hospital or clinic, the nurse should take the patient's vital signs. It is his or her responsibility to detect any abnormalities from the patient's normal state, and to establish if current medication(s) is having the desired effect.

Precautions

As there may be no knowledge of the patient's previous vital signs for comparison, it is important that the nurse be aware that there is a wide range of normal values that can apply to patients of different ages. The nurse should take as detailed a medical history from the patient as possible; any known medical or surgical history, prior measurements of vital signs, and details of current medication(s) should be recorded on the patient's chart. Any physical exertion prior to measurement of vital signs, such as climbing stairs, may affect the measurements. Thirty minutes prior to the taking of one's vital signs, the patient should not have consumed tobacco, caffeinated drinks, or alcohol.

Blood pressure is taken using a cuff that is the correct size for the patient; this will provide the most accurate reading. The reading can be 10 to 50 millimeters (mm) Hg too high with a cuff that is too small; a false reading of hypertension (high blood pressure) may result.

All types of sphygmomanometers cuff that can be filled with air, a hollow rubber bulb that pumps the air, and a glass tube that contains a column of mercuryhould be calibrated annually by a trained technician. This will ensure that equipment remains accurate.

Description

Vital signs are recorded from once hourly to four times hourly, and as required by the patient's condition.

Temperature is recorded to check for pyrexia (a febrile condition) or to monitor the degree of hypothermia. The body's normal temperature, taken orally, is 98.6°F (37°C), with a range of 97.8 to 99.1°F (36.5-37.2°C). A fever is a temperature of 101°F (38.3°C) or higher in an infant younger than three months or above 102°F (38.9°C) for older children and adults. Hypothermia is recognized as a temperature below 96°F (35.5°C).

The pulse is checked for any abnormalities of the heart by measuring the rate, rhythm, and regularity of the beat, as well as the strength and tension of the beat against the arterial wall. The strength of the beat is raised during conditions such as fever and lowered by conditions such as shock and intracranial pressure. The average rate for older children (age 12 and up) and adults is 72 beats per minute (bpm). Tachycardia is a pulse rate over 100 bpm, while bradycardia is a pulse rate of under 60 bpm.

Respirations are quiet, slow, and shallow when the adult is asleep, and rapid, deeper, and noisier during and after activity.

Average respiration rates at rest are:

• infants, 34 to 40 per minute
• children five years of age, 25 per minute
• older children and adults, 16 to 20 per minute

Tachypnea is rapid respiration above 20 per minute.

Blood pressure is recorded for older children and adults. A normal blood pressure reading is 120/70.

Preparation

The patient should be sitting down or lying comfortably to ensure that the readings are taken in a similar position each time. There should be little excitement, which can affect the results. The equipment required is a watch with a second hand, an electronic or mercury thermometer, an electronic or manual sphygmomanometer with an appropriate sized cuff, and a stethoscope.

Manufacturer's guidelines should be followed when taking a temperature with an electronic thermometer. The result displayed on the LCD screen should be read, then recorded in the patient's chart. Electronic temperature monitors do not have to be cleaned after use. They have protective guards that are disposed of after each use; these ensure that infections are not spread.

A mercury thermometer can be used to monitor a temperature by three methods:

• Axillary, under the armpit.
• 

  Normal vital signs, from the top: heart rate, arterial blood pressure (ABP), central venous pressure (CVP), pulmonary artery pressure (PAP), blood oxygen (PLETH), and respiration rate. (Photograph by James King-Holmes. Science Source/Photo Researchers. Reproduced by permission.)
  Oral, under the tongue. This method is never used with infants or very young children. Very young children might accidentally bite or break them. They also have difficulty holding oral thermometers under their tongues long enough for their temperatures to be accurately measured.
• Rectally, inserted into the rectum. This method is the gold standard for recording the temperature of infants. Although somewhat controversial because of potential discomfort and trauma to the baby, the investigators of a Harvard Medical School study, published in Archives of Pediatrics and Adolescent Medicine discovered that rectal thermometers were more accurate than ear thermometers in detecting high fevers. With the ability to detect low-grade fevers, rectal thermometers can be useful in discovering serious illnesses, such as meningitis and pneumonia. The tip of the thermometer is usually blue tipped to distinguish it from the silver tip of an oral/axillary thermometer.

To record the temperature using a mercury thermometer, one should shake down the thermometer by holding it firmly at the clear end and flicking it quickly a few times, with the silver end pointing downward. The health care provider who is taking the temperature should confirm that the mercury is below a normal body temperature.

The silver tip of the thermometer should be placed under the patient's right armpit. The arm clamps the thermometer into place, against the chest. The thermometer should stay in place for three to four minutes. After the appropriate time has elapsed, the thermometer should be removed and held at eye level. During this waiting period, the body temperature will be measured The mercury will have risen to a mark that indicates the temperature of the patient.

To record the oral temperature, the axillary procedure should be followed, except that the silver tip of the thermometer should be placed beneath the tongue for three to four minutes, then read as described previously.

In both cases, the thermometer is wiped clean with an antiseptic and stored in an appropriate container to prevent breakage.

The rectal thermometer, used to take accurate temperatures in infants, should be shaken down, as discussed previously. A small amount of water-based lubricant should be placed on the colored tip of the thermometer. With the infant lying on his or her back, the nurse must hold the child securely in place. The tip of the thermometer should then be inserted into the child's rectum carefully to avoid discomfort and possible injuryo more than one-half inch, or 2 cmnd held there for two to three minutes. After the thermometer is removed, it should be read (as described previously), and wiped clean with an antibacterial wipe. It should then be stored in an appropriate container to prevent breakage.

The pulse can be recorded anywhere that a surface artery runs over a bone, but the radial artery in the wrist is the more common point. To take the pulse, one should place his or her index, middle, and ring fingers over the radial artery. It is located above the wrist, on the anterior surface of the thumb side of the arm. Gentle pressure should be applied, taking care to avoid obstructing the patient's blood flow. The rate, rhythm, strength, and tension of the pulse should be noted. If there are no abnormalities detected, the pulsations can be counted for half a minute, and the result doubled. However, any irregularities discerned indicate that the pulse should be recorded for one minute. This will eliminate the possibility of error.

The fingers should be kept on the wrist, while the frequency of respirations in one minute is recorded. Every effort should be made to prevent patients from becoming aware that their breathing is being checked; if the patients were to realize this, they might consciously alter the rate at which they breathe. Both pulse and respiration results should be noted in the patient's chart.

Blood pressure is taken using a cuff that is the correct size for the patient. This will ensure the most accurate reading possible. With an electronic unit, the cuff is placed level with the heart and, if possible, wrapped around the upper left arm. Following the manufacturer's guidelines, the cuff is inflated and then deflated automatically, and the health care provider records the reading. If blood pressure is monitored manually, a cuff is placed level with the heart and wrapped around the upper arm. Placing a stethoscope over the brachial artery in front of the elbow with one hand and listening through the ear-piece, the cuff should be inflated until the artery is occluded, and no sound is heard. The cuff should then be inflated a further 10 mm Hg above the last sound heard. Opening the valve in the pump slowlyo faster than 5mm Hg per secondressure in the cuff is deflated until a sound is detected over the brachial artery. This point is noted as the systolic pressure. The pressure is further deflated until a soft muffled sound is heard. This allows the diastolic pressure to be taken. As in the case with in children, sounds will continue to be heard as the cuff deflates to zero.

The results are charted, with the systolic pressure being recorded first, and then the diastolic pressure. An entry in the patient's chart might appear as 120/70 (systolic/diastolic).

Aftercare

The patient should be made comfortable and reassured that recording vital signs is part of normal health checks, and that it is necessary to ensure that his or her health is being correctly monitored. Any abnormalities in the vital signs must be reported to the medical staff.

Complications

There is a nationwide initiative to ban the sale of mercury thermometers and promote mercury-free devices for monitoring blood pressure. Health activists are concerned about mercury contaminating the environment after it has been discarded. Several states have banned the use of products containing mercury and stores such as Wal-Mart, CVS, and Kmart have already stopped selling mercury thermometers. According to a study by the Mayo Clinic in March 2001, mercury-free devices can monitor information without compromising accuracy. The Environmental Protection Agency's October 1999 report, "Reducing Mercury Use in Health Care," advises using alternative mercury products to avoid the future need for increased regulations and to protect human health and wildlife by reducing unnecessary exposure to mercury.

Results

The vital signs are recorded and compared with normal ranges for the patient's age and medical condition. Based on these results, it is decided whether any further action needs to be taken.

Health care team roles

Patients may ask questions about specific concerns they have regarding their vital signs, or even about a particular disease. The nurse can counsel on the prevention of illness, but can direct the patient to the physician for specific questions.

KEY TERMS

Blood pressurehe pressure of the blood on the walls of the arteries, depending on the energy of the heart action, elasticity of the arterial walls, and volume and viscosity (resistance of flow) of blood. The tension of the blood in the arteries measured in millimeters of mercury by a sphygmomanometer or by an electronic device.

Occlusionlosed.

p.r.n.ro re nata; as required.

Respirationhe gaseous exchange between the tissue cells and the atmosphere.

Margaret A. Stockley, RGN