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Emergency Medicine & Critical Care

Hypoxaemia Management and Oxygen Therapy Guidelines

Management guidelines for hypoxaemia (low concentration of oxygen in the blood, typically SpO2 <90%), a life-threatening condition requiring prompt recognition, administration of supplemental oxygen, and treatment of the underlying cause.

Also known as: Low Blood Oxygen, Oxygen Therapy, Respiratory Distress Management

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Referral and warning signs

When to refer

Refer urgently to HC4/Hospital if: Patient requires high oxygen concentrations (e.g., >5 L/min via mask, or needing reservoir mask/CPAP/HFNC). Fails to maintain target SpO2 despite appropriate oxygen therapy. Shows signs of worsening respiratory distress or fatigue. Requires advanced airway management or mechanical ventilation. Underlying cause requires hospital-level management.

Red flags

  • SpO2 < 90% despite supplemental oxygen
  • Severe respiratory distress (marked recessions, grunting, gasping, inability to speak/feed)
  • Central cyanosis
  • Altered consciousness (confusion, lethargy, coma)
  • Signs of shock
  • Obstructed or absent breathing
  • Exhaustion or tiring

Signs and symptoms

  • Respiratory signs: Fast breathing (Tachypnoea - see age-specific rates in UCG p.88), Slow or irregular breathing (late sign), Difficulty breathing (dyspnoea), Use of accessory muscles of respiration, Nasal flaring, Head nodding (infants), Chest in-drawing (subcostal, intercostal, suprasternal recessions), Grunting (infants), Inability to speak in full sentences or feed (infants).
  • Cardiovascular signs: Tachycardia (early), Bradycardia (late/severe), Cyanosis (peripheral or central - may be late sign).
  • Neurological signs: Agitation, Anxiety, Confusion, Drowsiness, Lethargy, Irritability (infants), Convulsions, Coma (GCS < 10).
  • General: Extreme weakness, Prostration.

Risk factors

  • Underlying Conditions:
  • Respiratory: Severe Pneumonia, Severe Asthma attack, COPD exacerbation, COVID-19, Pertussis, Upper airway obstruction (e.g., foreign body, croup, epiglottitis), Pulmonary embolism, ARDS, Pneumothorax, Pulmonary oedema.
  • Cardiovascular: Heart Failure, Cardiac arrest, Shock (any type).
  • Neurological: Head Injury, Stroke, Seizures, Depressed consciousness from toxins/drugs.
  • Haematological: Severe anaemia, Carbon Monoxide poisoning.
  • Surgical/Trauma: Chest trauma, Post-operative complications.
  • Obstetric: Obstructed labour, Ruptured uterus, Pre-eclampsia/eclampsia, Post-C/S complications.
  • Neonatal: Respiratory Distress Syndrome (RDS), Transient Tachypnoea of the Newborn (TTN), Birth asphyxia (HIE), Neonatal Sepsis, Meconium Aspiration Syndrome.

Diagnosis

Clinical assessment

Suspected based on clinical signs and symptoms of respiratory distress or altered mental status (see signs/symptoms).

Investigations

  • Pulse Oximetry (SpO2): Essential non-invasive tool. Read consistently after stable waveform appears (20-30 secs). Target SpO2 >90% (or >92-95% in pregnancy). Note: Readings can be unreliable with poor perfusion, severe anaemia, nail polish, excessive movement.
  • Arterial Blood Gas (ABG) analysis: Gold standard, measures PaO2, PaCO2, pH, bicarbonate. Invasive, requires skill and equipment, often unavailable.
  • Clinical Assessment: Respiratory rate, work of breathing, auscultation, heart rate, BP, mental status.

Diagnostic criteria

Hypoxaemia indicated by: SpO2 <90% (<92-95% in Pregnancy). OR Presence of emergency/danger signs (absent/obstructed breathing, severe respiratory distress, central cyanosis, shock, coma, convulsions) irrespective of SpO2 reading. OR PaO2 <60 mmHg (on ABG).

Management

Non-pharmacological management

  • Ensure patent Airway (positioning, suctioning if needed).
  • Optimize Breathing (positioning - e.g., sit patient up unless contraindicated).
  • Support Circulation (treat shock, heart failure etc.).
  • Identify and aggressively treat the underlying cause (e.g., antibiotics for pneumonia, bronchodilators for asthma, diuretics for pulmonary oedema, chest drain for pneumothorax).

Pharmacological treatment

  • Oxygen Therapy: Administer supplemental medical oxygen immediately if hypoxaemia criteria met.
  • Target: Maintain SpO2 >90% (or >92-95% in pregnancy), using the lowest FiO2 possible.
  • Choice of Delivery Device and Flow Rate: Titrate based on patient age, severity, and SpO2 response. (See UCG Table p.90-91):
  • - Nasal Cannulae/Prongs: Low flow (0.5-6 L/min depending on age), delivers approx. 24-44% FiO2. Suitable for mild-moderate hypoxaemia.
  • - Simple Face Mask: Moderate flow (5-10 L/min - minimum 5L/min to prevent CO2 rebreathing), delivers approx. 40-60% FiO2. For moderate hypoxaemia.
  • - Face Mask with Reservoir Bag (Non-rebreather): High flow (10-15 L/min - ensure bag remains inflated), delivers approx. 60-90% FiO2. For severe hypoxaemia.
  • - Other devices (HC4/Hospital): CPAP (Continuous Positive Airway Pressure), BiPAP (Bilevel Positive Airway Pressure), High Flow Nasal Cannula (HFNC), Mechanical Ventilation.
  • Titration: Start oxygen (e.g., 1-5 L/min via nasal prongs, or higher if severe distress) and adjust flow rate based on SpO2 readings and clinical response. Escalate delivery device if target SpO2 not achieved (see UCG escalation flowchart p.92).
  • Weaning: Gradually reduce oxygen flow rate (e.g., by 1-2 L/min increments) once patient is stable with SpO2 consistently >90-92%. Monitor closely after each reduction for 15-60 mins. If SpO2 drops or distress increases, return to previous effective flow rate.
  • Follow specific Ugandan treatment algorithms/guidelines.

Monitoring

Continuous or frequent monitoring of SpO2 is essential. Monitor respiratory rate, work of breathing, heart rate, blood pressure, and mental status closely. Assess response to oxygen therapy and treatment of the underlying cause.

Complications

  • Hypoxia (inadequate oxygen supply to tissues)
  • Organ damage (especially brain, heart, kidneys) due to hypoxia
  • Respiratory failure
  • Cardiac arrest
  • Death
  • Oxygen toxicity (rare, usually with prolonged high FiO2)

Prevention

  • Prompt diagnosis and treatment of underlying respiratory, cardiovascular, and other conditions.
  • Vaccinations (e.g., Pneumococcus, Hib, Influenza, Pertussis, COVID-19).
  • Asthma action plans.
  • Safe delivery practices to prevent birth asphyxia.
  • Smoking cessation.

Patient education

  • Explain the reason for oxygen therapy (low oxygen levels in blood).
  • Explain the importance of treating the underlying condition.
  • If applicable, teach caregivers signs of respiratory distress and when to seek immediate medical care.
  • Reinforce adherence to treatment for chronic conditions (e.g., asthma inhalers).

Uganda-specific notes

Pulse oximetry is a vital tool; ensure devices are functional and used correctly. Refer to UCG tables for age-specific tachypnoea rates and guidance on oxygen delivery devices/flow rates. Consider common severe illnesses in Uganda like pneumonia, malaria, TB, sepsis, HIV-related complications as underlying causes. Ensure reliable oxygen source (cylinder, concentrator) and appropriate humidification, especially for prolonged use or high flows.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 1, Section 1.4 (pages 87-93, including tables and flowchart)

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