Vital Signs and Patient Assessment
Introduction to Vital Signs
Vital signs are the four (or five) primary physiological measurements that indicate the basic functions of the body. They are called “vital” because they reflect the patient’s fundamental state of health and detect changes that may indicate deterioration or improvement.
The four primary vital signs are:
- Temperature (Body temperature)
- Pulse (Heart rate)
- Respiration (Breathing rate)
- Blood Pressure (Arterial pressure)
A fifth vital sign often included is Oxygen Saturation (SpO₂) in modern clinical practice.
Vital signs are typically measured:
- On admission to any healthcare facility
- Before and after surgical procedures
- During routine physical examinations
- At regular intervals for admitted patients
- Whenever a patient’s condition changes
Normal vital signs for a healthy adult at rest:
| Vital Sign | Normal Range |
|---|---|
| Temperature | 36.5–37.5°C (97.7–99.5°F) |
| Pulse (Heart rate) | 60–100 beats/min |
| Respiration | 12–20 breaths/min |
| Blood Pressure | 120/80 mmHg (systolic/diastolic) |
| SpO₂ (Oxygen saturation) | 95–100% |
Body Temperature
Definition
Body temperature is the degree of heat maintained by the body, reflecting the balance between heat production and heat loss. The body maintains temperature through the hypothalamus (the “thermostat” in the brain).
Methods of Measurement
Oral (Mouth)
- Placement: Under the tongue, with mouth closed
- Normal: 36.5–37.5°C (97.7–99.5°F)
- Advantages: Convenient, relatively accurate
- Disadvantages: Affected by hot/cold drinks, smoking, breathing through mouth
- Contraindications: Unconscious patients, children under 5, mouth breathers, oral surgery
Rectal
- Placement: Inserted into rectum
- Normal: 0.5°C higher than oral (37.0–38.0°C)
- Most accurate core temperature measurement
- Used for: Infants, unconscious patients, patients who cannot have oral readings
- Contraindications: Rectal surgery, hemorrhoids, diarrhea
Axillary (Armpit)
- Placement: Under the arm
- Normal: 0.5°C lower than oral (36.0–37.0°C)
- Least accurate — often not recommended for adults
- Used when other methods are contraindicated
Tympanic (Ear)
- Placement: Infrared sensor in ear canal
- Reflects core temperature (close to hypothalamus)
- Normal: Similar to rectal — 0.5°C higher than oral
- Fast (2–3 seconds)
- Not affected by ambient temperature as much as oral
Temporal Artery (Forehead)
- Modern infrared scanning method
- Fast and non-invasive
- More accurate than tympanic in some studies
Fever Patterns
| Term | Temperature | Description |
|---|---|---|
| Normal | 36.5–37.5°C | Optimal body function |
| Subnormal | <36.5°C | Below normal; may indicate hypothermia, shock |
| Pyrexia | >37.5°C | Elevated temperature |
| Hyperpyrexia | >41°C | Very high fever — medical emergency |
| Intermittent | Fever comes and goes | Malaria, sepsis |
| Remittent | Fever fluctuates but doesn’t return to normal | Typhoid |
| Relapsing | Fever returns after afebrile period | Borrelia infections |
| Sustained/Continuous | Fever remains elevated without major fluctuations | Pneumonia |
Regulation
- Sweating: Primary cooling mechanism — sweat evaporates from skin
- Vasodilation: Blood vessels dilate → more heat loss through skin
- Shivering: Muscles generate heat to raise temperature
Pulse (Heart Rate)
Definition
The pulse is the rhythmic throbbing of an artery as blood is pumped through it by the heart. It is an indicator of heart rate and rhythm.
Sites for Pulse Measurement
| Site | Location | Used When |
|---|---|---|
| Radial | Thumb side of wrist (radial artery) | Most common — accessible, convenient |
| Carotid | Side of neck (carotid artery) | Emergency — when radial not accessible |
| Brachial | Inner elbow (brachial artery) | Blood pressure measurement |
| Apical | Left 5th intercostal space (at apex of heart) | Using stethoscope — most accurate for heart rate |
| Femoral | Groin (femoral artery) | Emergency — for infants |
| Popliteal | Behind knee | Lower limb circulation assessment |
| Dorsalis pedis | Top of foot | Lower limb circulation assessment |
| Temporal | Temple area | Used in infants when carotid is difficult |
Assessment of Pulse
When assessing pulse, evaluate:
1. Rate (Beats per minute):
- Tachycardia: >100 bpm (resting) — may indicate fever, anemia, anxiety, heart disease
- Bradycardia: <60 bpm — may indicate hypothyroidism, heart block, athletic heart
- Normal: 60–100 bpm
2. Rhythm:
- Regular: Equal intervals between beats
- Irregular (Arrhythmia): Unequal intervals — may indicate Atrial Fibrillation (AF), premature contractions
3. Volume (Strength):
- Full/Bounding: Strong pulse — hypertension, anxiety
- Weak/Thready: Difficult to feel — shock, heart failure
- Waterhammer/Corrigan’s: Very strong and quick — aortic regurgitation
4. Equality: Both radial pulses should be equal; unequal may indicate arterial blockage
Special Considerations
- Count for 30 seconds and multiply by 2 (if regular) or count for full 60 seconds (if irregular)
- In atrial fibrillation: Count apical pulse using stethoscope for one full minute (most accurate)
- In children: Rate is higher; normal for newborn is 100–160 bpm
Respiration
Definition
Respiration refers to the process of breathing — inhaling oxygen and exhaling carbon dioxide. The respiration rate is the number of breaths per minute.
Normal Values
- Adult: 12–20 breaths/min (average 16)
- Children: 20–30 breaths/min
- Infants: 30–60 breaths/min
Assessment
When observing respiration, note:
Rate:
- Bradypnea: <12 breaths/min — may indicate CNS depression, anesthesia, sleep
- Tachypnea: >20 breaths/min (adult) — fever, anxiety, lung disease, metabolic acidosis
- Apnea: Absence of breathing — medical emergency
Rhythm:
- Regular: Normal, even breathing
- Cheyne-Stokes: Breathing increases then decreases then stops — associated with severe heart failure, brain injury
- Biot’s: Irregular periods of apnea followed by regular breathing — CNS injury
Depth:
- Shallow: May indicate pain, pleurisy, fear
- Deep: May indicate metabolic acidosis (Kussmaul breathing in diabetic ketoacidosis)
Effort:
- Labored breathing (dyspnea): Shortness of breath — observable chest movement, flaring nostrils
- Stridor: High-pitched sound on inhalation — airway obstruction
- Wheezing: High-pitched sound on exhalation — asthma, COPD
Blood Pressure
Definition
Blood pressure is the pressure exerted by the blood against the walls of the arteries. It is measured in millimetres of mercury (mmHg).
Systolic: Maximum pressure when the heart contracts (ejects blood) — the top number Diastolic: Minimum pressure when the heart relaxes (fills with blood) — the bottom number
Example: 120/80 mmHg — Systolic 120, Diastolic 80
Normal Values
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | <120 | <80 |
| Elevated | 120–129 | <80 |
| Hypertension Stage 1 | 130–139 | 80–89 |
| Hypertension Stage 2 | ≥140 | ≥90 |
| Hypertensive Crisis | >180 | >120 |
Measurement Methods
Auscultatory Method (Mercury sphygmomanometer — gold standard)
Equipment: Sphygmomanometer (mercury or aneroid), stethoscope
Procedure:
- Patient seated or supine, arm supported at heart level
- Select appropriate cuff size (cuff bladder should encircle 80% of arm)
- Wrap cuff around upper arm (2–3 cm above antecubital fossa)
- Palpate radial pulse
- Inflate cuff until radial pulse disappears — note reading (approximate systolic)
- Place stethoscope over brachial artery (antecubital fossa)
- Deflate cuff slowly (2–3 mmHg per second)
- Note the pressure when the first Korotkoff sound is heard — systolic
- Continue deflating — sounds change from loud to soft
- Note when sounds disappear completely — diastolic
Korotkoff Sounds:
- Phase I: First clear tapping sound — systolic
- Phase II: Sound becomes softer
- Phase III: Sound becomes louder again
- Phase IV: Sound becomes muffled
- Phase V: Sound disappears — diastolic
Key points:
- Cuff too tight → falsely high reading
- Cuff too loose → falsely high reading
- Patient talking → falsely high reading
- Arm not supported → falsely high reading
- Legs crossed → falsely high reading
Palpatory Method
Used when auscultation is difficult (e.g., very low pressure). Palpate radial pulse while inflating cuff — note the pressure at which pulse disappears → this is the systolic.
Automated/Digital Devices
Used in clinical settings — oscillometric measurement. Advantages: Easy to use, no stethoscope required. Disadvantages: Less accurate in certain conditions (arrhythmias).
Factors Affecting Blood Pressure
Physiological:
- Age: BP increases with age (arteries stiffen)
- Gender: Higher in men until menopause
- Exercise: Temporary increase, then decreases with training
- Emotion: Anxiety increases BP
- Body position: Higher when standing; lower when lying
- After meals: Slight decrease
Pathological:
- Hypertension: Sustained elevated BP — risk of stroke, heart disease
- Hypotension: Low BP — shock, dehydration, heart failure
Documenting Vital Signs
Correct Documentation
Vital signs should be recorded with:
- Exact values (not approximate)
- Site (e.g., oral vs tympanic temperature; radial vs apical pulse)
- Time (24-hour format)
- Patient position (lying, sitting, standing)
- Any abnormal findings noted immediately
Trends
Single vital sign readings are less useful than trends — comparing readings over time to detect improvement or deterioration.
Early Warning Scores
Most hospitals use Early Warning Scores (EWS) or National Early Warning Score (NEWS) to identify patients at risk of deterioration. These scores assign points based on vital sign deviations and trigger escalation of care.
CTET/DOH Exam Focus
- Four primary vital signs: Temperature, pulse, respiration, blood pressure (SpO₂ often fifth)
- Normal ranges: Temp 36.5–37.5°C, pulse 60–100 bpm, RR 12–20/min, BP 120/80 mmHg, SpO₂ 95–100%
- Measurement sites: Oral (under tongue), rectal, axillary, tympanic (ear), temporal (forehead) for temperature; radial (most common), carotid (emergency), apical (most accurate) for pulse
- BP measurement: Auscultatory method — Korotkoff sounds Phase I (systolic) and Phase V (diastolic); cuff size critical
- Fever patterns: Intermittent, remittent, relapsing, continuous
- Pulse assessment: Rate, rhythm, volume; tachycardia vs bradycardia; arrhythmia
- Respiration: Rate, rhythm, depth, effort; Cheyne-Stokes, Biot’s breathing
- Documentation: Exact values, site, time, position, trends
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