Shortness of breath - undifferentiated
A streamlined, differential-led presentation for rapid clinical review.
Twenty-second review
- Dyspnea is the perception of respiratory effort produced by altered mechanics, gas exchange, circulatory function, metabolic demand, or central drive.
- Silent chest, exhaustion, inability to speak, cyanosis, shock, unilateral absent sounds, or decreasing LOC signals impending respiratory failure.
- Keep metabolic acidosis or anxiety in the differential; overlapping or concurrent illness remains possible.
- For shortness of breath - undifferentiated, trends and combinations of findings are more informative than one isolated vital sign.
Compare the clinical patterns
The repeated material is grouped inside each possibility. Open only the condition you need.
Pulmonary embolismTime-sensitive high-risk possibility
HPI
Clarify sudden or gradual; degree of distress; spo2 on room air and now.
Signs & symptoms
Sudden distress, pleuritic pain, shock, or asymmetric findings.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Pulmonary embolism may cause shortness of breath - undifferentiated through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Pulmonary embolism may have normal observations. Tachycardia, tachypnea, or hypoxemia increase concern; hypotension identifies hemodynamic compromise rather than being required for diagnosis.
Heart rate (bpm)
May riseTachycardia is common but neither sensitive nor specific.
Respiratory rate (breaths/min)
May riseTachypnea may be an early sign of increased ventilatory demand.
Oxygen saturation (SpO₂)
May fallHypoxemia may occur, but a normal saturation does not exclude PE.
Blood pressure (mmHg)
Often preservedHypotension suggests high-risk PE with obstructive shock.
Front-load in the triage report
- Pulmonary embolism: Sudden distress, pleuritic pain, shock, or asymmetric findings.
- Sudden or gradual?
- Degree of distress.
Tension pneumothoraxTime-sensitive high-risk possibility
HPI
Clarify degree of distress; spo2 on room air and now; new oxygen requirement.
Signs & symptoms
Sudden distress, pleuritic pain, shock, or asymmetric findings.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Compare air entry and sounds bilaterally; inspect effort, position, edema, JVP, chest pain, and DVT signs.
Brief pathophysiology
Tension pneumothorax may cause shortness of breath - undifferentiated through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Thoracic injury can evolve from respiratory compromise to obstructive or hemorrhagic shock. Integrate symmetry, air entry, work of breathing, and perfusion with serial observations.
Respiratory rate (breaths/min)
Often risesTachypnea commonly reflects pain, hypoxemia, or impaired mechanics.
Oxygen saturation (SpO₂)
May fallDesaturation supports significant gas-exchange impairment but may lag.
Heart rate (bpm)
Often risesTachycardia may accompany distress, hypoxia, or shock.
Blood pressure (mmHg)
May fall lateHypotension raises concern for tension physiology or significant hemorrhage.
Front-load in the triage report
- Tension pneumothorax: Sudden distress, pleuritic pain, shock, or asymmetric findings.
- Degree of distress.
- SpO2 on room air and now.
ObstructiveCommon presentation pattern
HPI
Clarify sudden or gradual; degree of distress; spo2 on room air and now.
Signs & symptoms
Wheeze, cough, fever, sputum, or known asthma/COPD may guide the working impression.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Obstructive may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Shock can be present before profound hypotension. Trend perfusion, mental status, pressure, and pulse characteristics; the direction varies with cause and treatment.
Blood pressure (mmHg)
May fallRelative change from baseline may be important before absolute hypotension appears.
MAP (mmHg)
May fallA falling MAP supports impaired perfusion but is not the only endpoint.
Heart rate (bpm)
Often risesTachycardia is common; neurogenic, toxic, paced, or medication effects can alter the response.
Pulse pressure (mmHg)
May narrowNarrow pulse pressure can reflect reduced stroke volume, although distributive states may differ.
Front-load in the triage report
- Wheeze, cough, fever, sputum, or known asthma/COPD may guide the working impression.
- Sudden or gradual?
- Degree of distress.
Infectious lung diseaseCommon presentation pattern
HPI
Clarify degree of distress; spo2 on room air and now; new oxygen requirement.
Signs & symptoms
Wheeze, cough, fever, sputum, or known asthma/COPD may guide the working impression.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Compare air entry and sounds bilaterally; inspect effort, position, edema, JVP, chest pain, and DVT signs.
Brief pathophysiology
Infectious lung disease may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Respiratory presentations require serial assessment of work of breathing and ventilation as well as oxygenation. A normal SpO₂ does not rule out serious ventilatory disease.
Respiratory rate (breaths/min)
Trend rate / effortA rising rate suggests distress; a late fall with fatigue may be ominous.
Oxygen saturation (SpO₂)
Trend against baselineInterpret the number with work of breathing and device limitations.
Heart rate (bpm)
May riseRate may reflect hypoxia, distress, treatment, or another cause.
Blood pressure (mmHg)
Trend perfusionHypotension suggests advanced disease or a concurrent shock state.
Front-load in the triage report
- Wheeze, cough, fever, sputum, or known asthma/COPD may guide the working impression.
- Degree of distress.
- SpO2 on room air and now.
Metabolic acidosisImportant alternative presentation
HPI
Clarify sudden or gradual; degree of distress; spo2 on room air and now.
Signs & symptoms
Rapid breathing with relatively clear lungs requires broader assessment.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Metabolic acidosis can resemble shortness of breath - undifferentiated through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Respiratory presentations require serial assessment of work of breathing and ventilation as well as oxygenation. A normal SpO₂ does not rule out serious ventilatory disease.
Respiratory rate (breaths/min)
Trend rate / effortA rising rate suggests distress; a late fall with fatigue may be ominous.
Oxygen saturation (SpO₂)
Trend against baselineInterpret the number with work of breathing and device limitations.
Heart rate (bpm)
May riseRate may reflect hypoxia, distress, treatment, or another cause.
Blood pressure (mmHg)
Trend perfusionHypotension suggests advanced disease or a concurrent shock state.
Front-load in the triage report
- Rapid breathing with relatively clear lungs requires broader assessment.
- Sudden or gradual?
- Degree of distress.
AnxietyImportant alternative presentation
HPI
Clarify degree of distress; spo2 on room air and now; new oxygen requirement.
Signs & symptoms
Rapid breathing with relatively clear lungs requires broader assessment.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Compare air entry and sounds bilaterally; inspect effort, position, edema, JVP, chest pain, and DVT signs.
Brief pathophysiology
Anxiety can resemble shortness of breath - undifferentiated through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Respiratory presentations require serial assessment of work of breathing and ventilation as well as oxygenation. A normal SpO₂ does not rule out serious ventilatory disease.
Respiratory rate (breaths/min)
Trend rate / effortA rising rate suggests distress; a late fall with fatigue may be ominous.
Oxygen saturation (SpO₂)
Trend against baselineInterpret the number with work of breathing and device limitations.
Heart rate (bpm)
May riseRate may reflect hypoxia, distress, treatment, or another cause.
Blood pressure (mmHg)
Trend perfusionHypotension suggests advanced disease or a concurrent shock state.
Front-load in the triage report
- Rapid breathing with relatively clear lungs requires broader assessment.
- Degree of distress.
- SpO2 on room air and now.
Findings that should escalate concern
- Silent chest, exhaustion, inability to speak, cyanosis, shock, unilateral absent sounds, or decreasing LOC signals impending respiratory failure.
- Pulmonary embolism or tension pneumothorax: Sudden distress, pleuritic pain, shock, or asymmetric findings.
Medication recognition
Continue the clinical pathway
Clinical and academic sources
Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.
BCEHS Handbook — specific CPGs
- A02: Patient AssessmentBC Emergency Health Services Handbook
Official BCEHS clinical practice guidance for patient assessment.
- A07: Oxygen AdministrationBC Emergency Health Services Handbook
Official BCEHS clinical practice guidance for oxygen administration.
- B01: Airway ManagementBC Emergency Health Services Handbook
Official BCEHS clinical practice guidance for airway management.
Supporting clinical and academic evidence
- CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians
Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.
- Guideline for oxygen use in adults in healthcare and emergency settingsBritish Thoracic Society
Peer-reviewed guidance for oxygen assessment, targets, delivery, and monitoring in acute illness.
- Acute dyspnea in the emergency department: a clinical reviewInternal and Emergency Medicine · 2023
Differential-led assessment of acute dyspnea, respiratory effort, gas exchange, and time-sensitive causes.