How do you assess difficulty of breathing in a patient?

Assessment of Difficulty of Breathing

Assess dyspnea systematically across three domains: sensory-perceptual experience (what breathing feels like), affective distress (how distressing it is), and functional impact (how it affects daily activities), using validated measurement tools appropriate to each domain. 1

Initial Clinical Assessment

Immediate Evaluation

• Never ignore a patient's complaint of difficulty breathing, even without objective signs, as subjective respiratory distress can indicate significant pathophysiology 2
• Position the patient upright immediately to optimize respiratory mechanics 2
• Obtain vital signs early: respiratory rate, heart rate, blood pressure, oxygen saturation, and assess general appearance of distress 2, 3
• Observe for 10 seconds to rate severity of respiratory distress (absent, slight, moderate, severe) - this correlates with oxygenation, respiratory rate, and signs of increased work of breathing 4

Physical Examination Findings

• Inspect for signs of increased work of breathing: nasal flaring, scalene muscle contraction, sternomastoid contraction, tracheal tug, thoracoabdominal paradox, gasping, and abdominal muscle contraction 4
• Auscultate for adventitious breath sounds: rhonchi (suggest airway secretions or obstruction), rales/crackles (suggest pulmonary edema or interstitial disease), wheezes (suggest bronchoconstriction), and pleural friction rub 3, 2
• Examine for jugular venous distention, cardiac murmurs/gallops, digital clubbing, and pallor 5
• Rating moderate-to-severe distress has 70% sensitivity and 92% specificity for serious respiratory dysfunction when combined with hypoxia, tachypnea, or signs of increased breathing effort 4

Measurement Domains and Tools

Sensory-Perceptual Experience (Intensity)

• Use single-item intensity scales: Visual Analog Scale (VAS), Borg scale (0-10), or numerical rating scales (0-10) 1
• These measure what breathing feels like to the patient in real-time 1
• Ask patients to describe the quality of dyspnea using specific descriptors, as certain sensations correlate with underlying pathophysiology 1, 5

Affective Distress (Unpleasantness)

• Assess how distressing the breathing feels using separate scales from intensity 1
• Single-item ratings can measure immediate unpleasantness or cognitive-evaluative responses about consequences 1
• Common pitfall: Single-item scales often conflate intensity with distress; clarify what you're asking the patient to rate 1

Functional Impact

• Modified Medical Research Council (mMRC) scale: Grades dyspnea from 0 (only with strenuous exercise) to 4 (too breathless to leave house) 6, 1
• Assess specific functional limitations: ability to climb stairs, shop, walk around the house 1
• Use quality of life questionnaires for long-term assessment of how dyspnea affects daily activities 1

Characterizing Dyspnea Quality

Descriptive Clusters

• "Inspiratory difficulty": "Breathing in requires effort," "My breath does not go in all the way" - suggests mechanical disadvantage of respiratory muscles 1
• "Air hunger/unsatisfied inspiration": "I feel a need for more air," "I cannot get enough air in" - indicates ventilatory shortfall relative to respiratory drive 1
• "Chest tightness": Relatively specific for bronchoconstriction (asthma) 5
• Document whether dyspnea is primarily inspiratory, expiratory, or both 1

Diagnostic Workup Based on Assessment

Initial Testing

• Chest X-ray, electrocardiogram, complete blood count, and basic metabolic panel in all patients with new dyspnea 5, 7
• Spirometry to identify obstructive or restrictive patterns 7
• Pulse oximetry and consider arterial blood gas if hypoxemia suspected 1, 2

Identifying Triggers and Patterns

• Exertion level that provokes symptoms 5
• Time of day patterns 5
• Environmental or occupational exposures 5
• Positional changes (orthopnea suggests heart failure, platypnea suggests intracardiac shunt) 5

Second-Line Testing (if initial workup nondiagnostic)

• Brain natriuretic peptide (BNP) or NT-proBNP to evaluate for heart failure 5, 7
• Transthoracic echocardiography for cardiac function assessment 5
• Pulmonary function testing with diffusing capacity (DLCO) for interstitial lung disease 5
• High-resolution CT chest for suspected parenchymal lung disease 5, 7

Classification Systems

By Urgency

• Immediate evaluation required: Presence of chest pain, syncope, hemoptysis, severe distress, or hemodynamic instability 6
• Outpatient evaluation appropriate: Chronic symptoms without alarm features 6

By Duration

• Chronic dyspnea: Present for >4-8 weeks (American College of Radiology definition) 6
• However, classification by etiology and functional severity is more clinically useful than duration alone 6

By Etiology

• Cardiac (heart failure, ischemia, arrhythmia) 6, 7
• Pulmonary (COPD, asthma, interstitial lung disease, pneumonia) 6, 7
• Neuromuscular 6
• Systemic (anemia, thyroid disease, deconditioning) 6, 7
• Psychological 6, 7

Special Considerations in ICU/Mechanically Ventilated Patients

Advanced Measurements

• Esophageal pressure measurement: Most direct assessment of respiratory muscle effort, requires balloon catheter 1, 8
• Work of breathing and pressure-time product (PTP): Direct measures of patient effort but require considerable technical expertise 1, 8
• Airway occlusion pressure (P0.1): Easy to measure in ventilated patients, high values signal increased respiratory motor output 1
• Rapid shallow breathing index (f/VT ratio): Most reliable simple predictor of weaning outcome 1

Monitoring During Mechanical Ventilation

• Observe for scooped contour of airway pressure tracing during assisted ventilation, indicating patient effort 1
• Assess for thoracoabdominal paradox, which occurs with elevated respiratory load 1
• Tachypnea is sensitive but not specific for deteriorating clinical status 1

Common Pitfalls to Avoid

• Do not dismiss subjective dyspnea complaints when objective findings are minimal, especially in elderly patients who may have atypical presentations 2, 5
• Do not attribute dyspnea to deconditioning without excluding cardiopulmonary disease first 5
• Do not use single-item scales without clarifying whether you're measuring intensity versus distress - these are distinct constructs 1
• Do not overlook environmental/occupational exposures that may cause hypersensitivity pneumonitis 5
• Do not rely solely on maximum inspiratory pressure in ICU patients - it has poor reproducibility 1
• Normal white blood cell count does not exclude infection, particularly in elderly patients with blunted inflammatory responses 2