Respiratory Failure
Related Subjects: Asthma
|Acute Severe Asthma
|Exacerbation of COPD
|Pulmonary Embolism
|Cardiogenic Pulmonary Oedema
|Pneumothorax
|Tension Pneumothorax
|Fat embolism
|Hyperventilation Syndrome
|Acute Respiratory Distress Syndrome (ARDS)
|Respiratory Failure
🚨 Emergency Management at the Bedside
| ⚕️ Step |
Type 1 (Hypoxaemic (PaO₂ < 8 kPa) ) |
Type 2 (Hypoxaemic (PaO₂ < 8 kPa) and Hypercapnic) |
| 🫁 Oxygen |
High-flow O₂ (non-rebreather) → SpO₂ 94–98% |
Controlled O₂ (Venturi 24–28%) → SpO₂ 88–92% |
| 🎯 Treat cause |
- Diuretics → pulmonary oedema
- Chest drain → pneumothorax
- Antibiotics → pneumonia
- Anticoagulation → PE
|
- Bronchodilators/steroids → COPD/asthma
- Chest physio/suction → sputum plugs
- Stop/reverse sedatives → Naloxone, Flumazenil
|
| 💻 Support |
Consider CPAP, NIV, or invasive ventilation ± ECMO |
NIV (BiPAP): IPAP 10 / EPAP 5; escalate to intubation if failing |
| 📞 Escalation |
Urgent ITU referral if deteriorating (tachycardia, tachypnoea, hypotension, confusion, rising PaCO₂ or falling PaO₂) |
It is quite possible for a patient with COPD to also have a PE.
Patients may go from Type 1 to Type 2 when they tire, hypoventilate, or receive sedation.
Intubation and ventilation can treat both types.
📖 About
- 🫁 Respiratory failure (PaO₂ < 8 kPa) is a common emergency.
- Reflects failure of the lungs to perform gas exchange: oxygenation ± CO₂ clearance.
- Classified as Type 1 (hypoxaemic) or Type 2 (hypercapnic).
- 📟 Pulse oximetry → O₂ saturation only, no CO₂ info.
- 💉 ABG → PaO₂, PaCO₂, pH, HCO₃⁻, acid–base status.
📊 Classification
| Type |
Oxygen (PaO₂) |
Carbon Dioxide (PaCO₂) |
| Type 1 🩵 |
< 8 kPa |
< 6 kPa |
| Type 2 ❤️ |
< 8 kPa |
> 6 kPa |
💨 How much Oxygen?
- 🌍 Most patients: aim SpO₂ 94–98%.
- 🌫️ COPD / Type 2 RF: aim 88–92%, PaO₂ > 7 kPa.
- ⬆️ If sats < 94% → ↑ O₂ (unless chronic hypercapnic COPD).
- ⬇️ If sats > 98% → ↓ O₂.
- ⚠️ Special cases (e.g. COVID O₂ conservation): follow local guidance.
🩺 Causes
- Type 1 (Hypoxaemic, V/Q mismatch or shunt):
- 🌊 Pulmonary oedema
- 🩸 Pulmonary embolism
- 🔥 ARDS
- 🌪️ Asthma
- 🦠 Pneumonia
- 🏔️ High altitude
- 🚫 Upper airway obstruction
- Type 2 (Hypercapnic, alveolar hypoventilation):
- 😮💨 Fatigue in COPD/pneumonia
- 🧠 CNS: stroke, tumour, sedation, head injury
- 🫁 COPD exacerbation
- 💪 Neuromuscular weakness (GBS, MND, SMA, polio, dystrophies, Pompe)
- 🦴 Chest wall deformity (flail chest, kyphoscoliosis)
- ⚖️ Obesity hypoventilation, alcohol, sedatives
- 🟤 Sputum retention, mucus plugging
🔍 Investigations
- 📟 Pulse oximetry → O₂ only.
- 💉 ABG → gold standard.
- 📈 ECG → arrhythmias, RV strain, S1Q3T3 (PE).
- 🩻 CXR → pneumonia, COPD, pneumothorax.
- 🧪 CTPA if Wells suggests PE in Type 1 RF.
⚕️ Management of Type 1 RF
- ABC; give high-flow O₂ (unless risk of hypercapnia).
- 🎯 Treat cause:
- 💊 Diuretics → pulmonary oedema
- 🩹 Chest drain → pneumothorax
- 🦠 Antibiotics → infection
- 💨 Bronchodilators/steroids → asthma/COPD
- 🩸 Anticoagulation/thrombolysis → PE
- May require CPAP, NIV, invasive ventilation ± ECMO.
⚕️ Management of Type 2 RF
- ABC; controlled O₂ (24% Venturi, aim PaO₂ > 7 kPa).
- 🧪 Watch for CO₂ retention: warm peripheries, bounding pulse, drowsiness, flap.
- 🫁 Typical COPD signs: prolonged expiration, wheeze, hyperinflated chest.
- ❤️ Right heart failure signs: oedema, raised JVP, hepatomegaly, ascites.
- 🧹 Chest physio ± suction for sputum plugs.
- NIV (BiPAP): start IPAP 10, EPAP 5 cm H₂O.
- If failing → intubation & ventilation:
- FiO₂ 1.0
- Tidal vol 6–10 ml/kg
- RR 10–12
- PEEP 5 cm H₂O
- Consider ECMO if refractory.
- 💊 Drug-induced: Naloxone (opiates), Flumazenil (benzos).
🚨 Important Scenarios
- ⚡ Impending arrest: HR >120, RR >30, hypotension, agitation, confusion, rising PaCO₂/falling PaO₂ → urgent ITU call.
- 😵 Mask intolerance: confused patients → nasal prongs 1–2 L/min safer.
- 🎭 High-flow O₂ with normal PaO₂ can mask deterioration → repeat ABG.
- 🌪️ Asthma + “normal PaCO₂” = fatigue/worsening → escalate urgently.
- 🧪 Low PaO₂ but normal sats may be venous sample error.
