Vital Signs

Original Editor - Manisha Shrestha Top Contributors - Manisha Shrestha, Lucinda hampton and Kim Jackson

Original Editor - User Name

Top Contributors - Manisha Shrestha, Lucinda hampton and Kim Jackson  

Introduction

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Vital signs are:

  • Indicators of one's health condition and the assurance of proper circulatory, respiratory, neural, and endocrinal functions.
  • A mechanism to universally communicate a patient's condition and severity of the disease.[1]
  • The simplest, cheapest, and probably the most important information gathered on hospitalized patients.[2]
  • An objective measurement for the essential physiological functions of a living organism.
  • Named "vital" as their measurement and assessment is the critical first step for any clinical evaluation.[3]

Traditionally the vital signs consist of:

  1. Temperature
  2. Pulse rate
  3. Blood pressure
  4. Respiratory rate.

Studies have only found pulse oximetry and smoking status to have significance in patient outcomes and may be included[4].

Vital signs can be influenced by a number of factors. It can vary based on age, time, gender, medication, or a result of the environment. 

  • Healthcare providers must understand the various physiologic and pathologic processes affecting these sets of measurements and their proper interpretation.[3]

Vital signs play an important role in emergency departments (ED) and on the wards, to determine patients at risk of deterioration.

  • The degree of vital sign abnormalities may also predict the long-term patient health outcomes, return emergency room visits, and frequency of readmission to hospitals, and utilization of healthcare resources. [3]
  • Vital signs help to predict physical therapy indications, contraindications, and outcomes.[5]
  • Vital signs are appropriate to characterize or quantify cardiovascular and pulmonary signs and symptoms as part of an assessment of aerobic capacity and endurance.[5]

Components

Temperature.jpg

Body Temperature

The normal body temperature for a healthy adult is approximately 98.6 degrees Fahrenheit/37.0 degrees centigrade. The human body temperature typically ranges from 36.5 to 37.5 degrees centigrade (97.7 to 99.5 degrees Fahrenheit).

Health care providers use the axillary, rectal, oral, and tympanic membrane most commonly used to record body temperature, and the electronic and infrared thermometers are the devices most commonly used.

Sites for measurement of body temperature

  1. Oral temperature: It is the most commonly used method, is considered very convenient and reliable. Here we place the thermometer under the tongue and close the lips around it. The posterior sublingual pocket is the area that gives the highest reliability.
  2. Tympanic temperature: In this method, the thermometer is inserted into the ear canal. This site is convenient but less accurate and hence not recommended.
  3. Axillary temperature: In this, we place the thermometer in the axilla while adducting the arm of the patient. This site is convenient but generally considered less accurate and hence not recommended.
  4. Rectal temperature: The thermometer is inserted through the anus into the rectum after applying a lubricant. This method is very inconvenient, but since it measures the internal measurement, it is very reliable. It is usually considered the "gold standard" method of recording temperature.
  5. Skin temperature: Digital thermometer can be used to measure the quick temperature from the skin of the forehead. It has been widely used now in this COVID-19 pandemic to avoid cross-contamination as the thermometer is kept 3-5cm away from the patient's forehead.

Body temperature is affected by many sources of internal and external variables. Besides the site of measurement, the time of day is an essential factor leading to variability in the temperature record, secondary to the circadian rhythm. Other factors influencing body temperature are gender, recent activity,  a person's relative physical fitness, food, and fluid consumption, and, in women, the stage of the menstrual cycle. [3]

Pulse Rate

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Pulse rate is defined as the wave of blood in the artery created by contraction of the left ventricle during a cardiac cycle. The most common sites of measuring the peripheral pulses are the radial pulse, ulnar pulse, brachial pulse in the upper extremity, and the posterior tibialis or the dorsalis pedis pulse as well as the femoral pulse in the lower extremity. Clinicians also measure the carotid pulse in the neck. In day to day practice, the radial pulse is the most frequently used site for checking the peripheral pulse, where the pulse is palpated on the radial aspect of the forearm, just proximal to the wrist joint. 

Parameters for assessment of pulse

  1. Rate: The normal range used in an adult is between 60 to 100 beats /minute with rates above 100 beats/minute and rates and below 60 beats per minute, referred to as tachycardia and bradycardia, respectively. Changes in the rate of the pulse, along with changes in respiration is called sinus arrhythmia. In sinus arrhythmia, the pulse rate becomes faster during inspiration and slows down during expiration.
  2. Rythym: Assessing whether the rhythm of the pulse is regular or irregular is essential. The pulse could be regular, irregular, or irregularly irregular. Irregularly irregular pattern is more commonly indicative of processes like atrial flutter or atrial fibrillation.
  3. Volume: Assessing the volume of the pulse is equally essential. A low volume pulse could be indicative of inadequate tissue perfusion; this can be a crucial indicator of indirect prediction of the systolic blood pressure of the patient.
  4. Symmetry: Checking for symmetry of the pulses is important as asymmetrical pulses could be seen in conditions like aortic dissection, aortic coarctation, Takayasu arteritis, and subclavian steal syndrome.
  5. Amplitude and rate of increase:  Low amplitude and low rate of increase could be seen in conditions like aortic stenosis, besides weak perfusion states. High amplitude and rapid rise can be indicative of conditions like aortic regurgitation, mitral regurgitation, and hypertrophic cardiomyopathy.[3]

Respiratory Rate

The respiratory rate/the number of breaths per minute is defined as the one breath to each movement of air in and out of the lungs. The normal breathing rate is about 12 to 20 beats per minute in an average adult. In the pediatric age group, it is defined by the particular age group.

Parameters that need to be included are its rate, depth of breathing, and its pattern rate of breathing.

  1. Rates: Rates higher or lower than expected are termed as tachypnea and bradypnea, respectively. Tachypnea described as a respiratory rate more than 20 beats per minute could occur in physiological conditions like exercise, emotional changes, pregnancy, and pathological conditions like pain, pneumonia, pulmonary embolism, asthma, etc. Bradypnea which is ventilation less than 12 breaths/minute can occur due to worsening of any underlying respiratory condition leading to respiratory failure or due to usage of central nervous system depressants like alcohol, narcotics, benzodiazepines, or metabolic derangements. Apnea is the complete cessation of airflow to the lungs for a total of 15 seconds which may appear in cardiopulmonary arrests, airway obstructions, the overdose of narcotics and benzodiazepines.
  2. Depth of breathing: Hyperpnea is described as an increase in the depth of breathing. Hyperventilation, on the other hand, is described as both an increase in the rate and depth of breathing and hypoventilation describes the decreased rate and depth of ventilation. Depth of breathing involves what muscle groups they are using—for example, the sternocleidomastoid (accessory muscles) and abdominal muscles—the movement of the chest wall in terms of symmetry. The inability to speak in full sentences or increased effort to speak is an indicator of discomfort when breathing.[6]
  3. The pattern of breathing: There are many conditions which are based on the variation in the pattern of breathing. Biot’s respiration is a condition where there are periods of increased rate and depth of breathing, followed by periods of no breathing or apnea. Cheyne-Stokes respiration is a peculiar pattern of breathing where there is an increase in the depth of ventilation followed by periods of no breathing or apnea. Kussmaul’s breathing refers to the increased depth of ventilation, although the rate remains regular. Orthopnea refers to difficulty in respiration occurring on lying horizontal but gets better when the patient sits up or stands. Paradoxical ventilation refers to the inward movement of the abdominal or chest wall during inspiration, and outward movement during expiration, which is seen in cases of diaphragmatic paralysis, muscle fatigue, trauma to the chest wall.[3]

Blood Pressure

Blood Pressure.jpg

Blood pressure is the force of circulating blood on the walls of the arteries, mainly in large arteries of the systemic circulation. Blood pressure is taken using two measurements: systolic (measured when the heartbeats, when blood pressure is at its highest) and diastolic (measured between heartbeats, when blood pressure is at its lowest). Blood pressure is written with the systolic blood pressure first, followed by the diastolic blood pressure.[7]

The direct measurement of BP requires an intra-arterial assessment but it is not practical in clinical practice so BP is measured via non-invasive means. Earlier BP is measure with a stethoscope while watching a sphygmomanometer (i.e auscultation). However, semiautomated and automated devices that use the oscillometry method, which detects the amplitude of the BP oscillations on the arterial wall, have become widely used over the past 2 decades.

The brachial artery is the most common site for BP measurement.

Key Points for Accurately Measuring BP

All healthcare providers should be aware of making sure all the following pre-requisites are met before checking the blood pressure of the patient.

The patient should:

  • Not have taken any caffeinated drink at least 1 hour before the testing and should not have smoked any nicotine products at least 15 minutes before checking the pressure. They
  • Should have emptied their bladder should be before checking the blood pressure. Full bladder adds 10 mm Hg to the pressure readings.
  • It is advisable to have the patient be seated for at least 5 minutes before checking his/her pressure. This step takes care of or at least minimizes the higher readings that could have occurred secondary to rushing in for the clinic appointment.
  • The providers should not be having a conversation with the patient while checking his blood pressure. Talking or active listening adds ten mmHg to the pressure readings.
  • The patient’s back and feet should be supported, and their legs should be uncrossed. Unsupported back and feet add six mmHg to the pressure readings. Crossed legs add 2 to 4 mmHg to the pressure readings.
  • The arm should be supported at the heart level. Unsupported arm leads to 10 mmHg to the pressure readings. The patient’s blood pressure should get checked in each arm, and in younger patients, it should be tested in an upper and lower extremity to rule out the coarctation of the aorta.
  • Cuff placement should be on a bare arm and not put over sweaters, coats, or other clothing. Using the correct cuff size is very important. Smaller cuff sizes give falsely high, and larger cuff sizes give a falsely lower blood pressure reading[3]

Normative value

According to the 2017 ACC/AHA Guideline for the Prevention, Detection, Evaluation, and Management of High BP in Adults.[8]

BP Category SBP, mm Hg DBP, mm Hg
Normal <120 and <80
Elevated 120–129 and <80
Hypertension
Stage 1 130–139 or 80–89
Stage 2 ≥140 or ≥90

Variability of Vital Signs in the Geriatric Age Group

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Since vital signs are an indication of the changes in our physiological processes, they tend to change as we age.

As we age:

  • Our core body temperature tends to be lower
  • The ability of the body to change with different kinds of stressors becomes minimized.
  • Subtle variation from the core body temperature can be a significant finding as fever in an older patient often indicates a more severe infection and is associated with increased rates of life-threatening consequences.
  • The blood vessels have higher arterial stiffness, leading to higher systolic blood pressure and increased pulse pressure.
  • Respiratory rate is the most neglected of the vital signs reported in hospitalized patients but is more sensitive than other vital signs in picking up a critically ill patient.
  • Resting heart rate is often observed to increase with age due to deconditioning and autonomic dysregulation[3]

Resources

References

  1. Teixeira CC, Boaventura RP, Souza AC, Paranaguá TT, Bezerra AL, Bachion MM, Brasil VV. Vital signs measurement: an indicator of safe care delivered to elderly patients. Texto & Contexto-Enfermagem. 2015 Dec;24(4):1071-8.
  2. Brekke IJ, Puntervoll LH, Pedersen PB, Kellett J, Brabrand M. The value of vital sign trends in predicting and monitoring clinical deterioration: A systematic review. PloS one. 2019 Jan 15;14(1):e0210875.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Sapra A, Malik A, Bhandari P. Vital Sign Assessment. InStatPearls [Internet] 2019 Dec 28. StatPearls Publishing.
  4. Sapra A, Malik A, Bhandari P. Vital Sign Assessment. InStatPearls [Internet] 2019 Dec 28. StatPearls Publishing.Available from:https://www.ncbi.nlm.nih.gov/books/NBK553213/ (last accessed 7.10.2020)
  5. 5.0 5.1 Thistle VG, Basskin AL, Shamus E, Jeffreys-Heil R. Clinical decision making regarding the use of vital signs in physical therapy. Pediatrics. 2016;1:5-9.
  6. Rolfe S. The importance of respiratory rate monitoring. British Journal of Nursing. 2019 Apr 25;28(8):504-8.
  7. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/blood-pressure
  8. Muntner P, Shimbo D, Carey RM, Charleston JB, Gaillard T, Misra S, Myers MG, Ogedegbe G, Schwartz JE, Townsend RR, Urbina EM. Measurement of blood pressure in humans: a scientific statement from the American Heart Association. Hypertension. 2019 May;73(5):e35-66.