Vital Signs

Learning Objectives

• Explain the physiologic processes involved in homeostatic regulation of vital signs (temperature, pulse, respirations, blood pressure).

• Compare and contrast factors that influence body temperature, pulse, respiration, and blood pressure.

• Identify sites for assessing temperature, pulse, and blood pressure.

• Demonstrate knowledge of normal ranges for these vital signs in adults.

• Document vital signs accurately.

Indicators of Physiologic Functioning

• Vital signs serve as key indicators of physiological functioning and reflect overall health status:

  • Temperature

  • Pulse

  • Respirations

  • Pulse Oximetry

  • Blood Pressure

  • Pain Level

When to Assess Vital Signs

• Vital signs should be assessed:

  • Upon admission to healthcare facilities.

  • As per institutional policies and procedures.

  • Upon any change in the patient’s condition.

  • When there is a loss of consciousness.

  • Before and after surgical or invasive procedures.

  • Before and after activities with increased risk (e.g., ambulation after surgery).

  • Before administering medications affecting cardiovascular or respiratory function.

  • Whenever the patient reports a change in status or experiences pain/distress.

Physiology of Body Temperature

• The hypothalamus regulates thermoregulation:

  • Balances heat production and loss.

• Key factors affecting body temperature:

  • Time of day

  • Biological sex

  • Age

  • Physical activity

  • State of health

  • Environmental temperatures.

• Core body temperature is most accurately measured at:

  • Intracranial

  • Intrathoracic

  • Intra-abdominal

• Optimal body temperature range for cellular function: 36°C to 37.5°C (98.6°F).

Circadian Rhythm and Body Temperature

• Circadian Rhythm: Predictable fluctuations in body temperature;

  • Lower in the morning, peaks between 1500-1800.

• Age and Biological Sex:

  • Older adults may have different temperature responses.

  • Sensitivity varies between genders.

• Environmental influences: Extreme cold leads to hypothermia; extreme heat results in hyperthermia.

Pyrexia (Fever)

• Fever defined:

  • Temperature exceeding 38°C (100.4°F).

  • Pyrexia can indicate a medical issue; very high (>40°C or 104°F) is dangerous.

• Signs and Symptoms:

  • Loss of appetite

  • Headache

  • Hot, dry skin

  • Thirst

  • Muscle aches

  • Fatigue.

• Classification:

  • Febrile patient has increased temperature.

  • Afebrile means normal temperature.

  • Hyperpyrexia (≥41°C or 106°F) is a medical crisis.

Treatment for Pyrexia

• Acknowledge fever as immune response; treatment focuses on comfort and preventing complications:

  • Pharmaceutical: Antipyretics for bacterial infection.

  • Non-Pharmaceutical: Cool baths, cooling blankets, remove extra clothing, encourage oral fluids to prevent dehydration.

Treatment for Hypothermia

• Symptoms:

  • Poor coordination

  • Slurred speech

  • Hallucinations

  • Decreased respiration, HR, and BP.

• Treatment strategies:

  • Warm blankets and fluids.

  • Bair Hugger for controlled warmth.

Methods of Temperature Assessment

• Types of thermometers:

  • Infrared

  • Tympanic

  • Electronic (rectal/oral/axillary).

Sites for Assessing Temperature

• Oral:

  • Under tongue (sublingual pocket), no hot/cold drinks 20 min prior; not for small children.

  • Leave in place for 3 min.

• Axillary:

  • Center of axilla; less accurate. Leave for 5-10 min. Measures 0.5°C lower than oral.

• Rectal:

  • Lubricated insertion, 2-3 min. Measures 0.5°C higher than oral.

• Ear (Tympanic):

  • Quick, sensitive to core temp changes (2-3 seconds), prone to distortion if cerumen present.

Assessing Pulse

• Caused by left ventricle contraction producing blood surge; can be palpated at various arteries:

  • Carotid

  • Brachial

  • Radial

  • Femoral

  • Popliteal

  • Posterior tibial

  • Dorsalis pedis

• Assess:

  • Rate

  • Rhythm

  • Amplitude (volume of blood against artery walls).

Procedure for Assessing Pulses

• Peripheral pulse: use 2nd-4th fingers to apply light pressure.

  • Count for 30 seconds, multiply by 2; if irregular, count radial for 1 minute.

• Apical pulse: listen at apex for a full minute.

Pulse Characteristics

• Rate: Normal 60-100 bpm (average 80 bpm).

  • Tachycardia: >100 bpm

  • Bradycardia: <60 bpm.

• Rhythm: Regular/irregular beats.

• Amplitude:

  • Weak/thready (low volume)

  • Full/bounding (higher than normal)

  • Imperceptible (unable to feel).

Assessing Respirations

• Reflect gas exchange between oxygen and carbon dioxide, both autonomic and voluntary.

  • Assess rate, rhythm, depth immediately following pulse check.

• Normal Respiratory Rate: 12-20 breaths/minute.

  • Tachypnea: Increased rate

  • Bradypnea: Decreased rate

  • Apnea: No breathing.

Additional Respiratory Assessments

• Assess:

  • Depth of air inhaled/exhaled (shallow vs. deep).

  • Rhythm (consistency of breaths).

  • Character (normal vs. adventitious sounds).

  • Dyspnea refers to difficulty in breathing.

Blood Pressure Assessment

• Blood pressure (BP): force of blood against arterial walls.

  • Systolic: Pressure during heart contraction.

  • Diastolic: Pressure during heart relaxation.

• Factors affecting BP:

  • Body position

  • Medications

  • Age

  • Biological sex

  • Race

  • Stress.

Blood Pressure Measurements

• Normal BP: <120/80 mmHg.

• **Categories: **

  • Hypotension: <90/60 mmHg.

  • Prehypertension: 120-129 systolic and 80 diastolic.

  • Stage 1 hypertension: 130-139 systolic and 80-89 diastolic.

  • Stage 2 hypertension: >140 systolic, >90 diastolic.

  • Hypertensive Crisis: >180.

BP Assessment Considerations

• Correct cuff size is crucial:

  • Cuff should cover 40% of arm circumference and bladder 2/3 of arm.

• Support arm at heart level; wrong positioning leads to inaccurate readings.

• Listen for Korotkoff sounds when cuff pressure is released to document BP.

Pulse Oximetry

• Non-invasive method to measure oxygen saturation (SpO2).

• Probes can be placed on fingers, ears, nose, or toes.

• Factors to consider:

  • Remove thick nail polish

  • Ensure oximeter reads at constant value.

Pain Assessment - PQRST Scale

• Key questions for pain assessment:

  • Provocation/Palliation: What brings the pain on? What makes it better/worse?

  • Quality: How would you describe the pain (stabbing, burning, sharp)?

  • Region/Radiation: Where is the pain located? Does it spread?

  • Severity: How bad is the pain now? At its worst?

  • Time: When did the pain start? Is it constant or intermittent?

Vital Signs Assessment

• Vital signs may reveal sudden changes in health status and can indicate a need for further assessment.

• Normal ranges can vary; establish a baseline set of vital signs to identify significant changes.