Respiratory System and Lung Sounds

Assessment of Lungs and Thorax

• Pattern is important to ensure coverage of all lung fields and listening to the lateral portion of the lungs (side of body).
• Expected normal findings:
  • Clear lung sounds
  • No adventitious lung sounds (crackles or wheezing)
  • Bronchovesicular sounds over major bronchi
  • Vesicular sounds over peripheral lung fields

Bronchial Sound

• Heard on anterior chest over trachea
• Characterized as loud, high-pitched

Bronchovesicular Sound

• Heard closest to bronchi
• Louder than vesicular sounds
• Even on inspiration and expiration

Vesicular Sound

• Heard on lateral part of body
• Whisper-like sound
• Louder on inspiration
• Associated with smaller airways

Adventitious Sounds

• Examples:
  • Fine crackles (high-pitched crackling)
  • Coarse crackles (fluid in lungs, sounds like drinking through a straw)
  • Pleural friction fremitus (friction in pleural tissue due to inflammation)
  • Wheeze-sibilant (obstruction, air escaping through small airway, narrowed)
  • Wheeze-sonorous rhonchi (obstruction, air escaping through small airway, narrowed on exhale)
  • Stridor (upper airway obstruction, something lodged in throat, common in children)

Assessment of Respiratory Rate, Rhythm, and Pulse Oximetry

• Respiratory rate and rhythm:
  • Regular, even, effortless, symmetric, consistent
  • Rate: 12-20 breaths per minute
• Pulse oximetry:
  • Noninvasive method to assess arterial oxygen saturation (SPO2)
  • Normal values: 97%-99%

Inspection

• Respiratory rate and rhythm:
  • Rate: 12-20 breaths per minute
  • Rhythm: consistent, even, regular
• Chest rise and fall symmetrical
• No accessory muscle use or retractions
• Comfortable positioning, not in tripod position
• Color appropriate for ethnicity, no cyanosis
• Chest wall configuration:
  • Normal: AP:T is 1:2
  • Abnormal: AP:T 1:1, barrel chest, irreversible (e.g., COPD)
• Nails:
  • Abnormal: Clubbing caused by chronic hypoxia
• Posterior thorax:
  • Abnormal: Asymmetry and dorsal curvature (e.g., scoliosis, kyphosis)

Palpation

• What to feel for:
  • Abnormal findings: crepitus, friction, masses, temperature
  • Normal findings: warm, no masses or tenderness
• Technique:
  • Hands move with breathing starting at T9 vertebrae
  • Go from left to right to down and then right to left motions
• Tactile fremitus:
  • Palpable vibration; sounds generated from larynx
  • Technique: use palmar base of fingers

Percussion

• Client position:
  • Slightly bent forward
• Compare bilaterally and note any symmetry
• Avoid body prominences
• Specific technique:
  • Starting at apices and going side-to-side, working way down
• Findings:
  • Normal: resonance (low-pitch, clear, and hollow sound)
  • Abnormal: dull; can indicate fluid in lungs, pneumonia, or tumor
• Pattern:
  • Why do we hear different sounds over bones than over lung tissue?
    • Bones are denser, giving a dull flat sound
  • Compare bilaterally

Auscultation

• Position:
  • Sit upright, relaxed, hands on knees
• How to breathe:
  • In and out of mouth every time stethoscope makes contact with skin
• How far down to listen:
  • To lateral part of back
• Place on foot (for babies), finger, or toe
• Inaccurate readings can be caused by:
  • Carbon monoxide binding to Hgb instead of oxygen
  • Anemia