Type 1 and Type 2 Respiratory Failure: Prevent, Detect, Intervene - Medtronic

Respiratory failure occurs when the respiratory system fails to maintain gas exchange, resulting in hypoxia or hypercapnia. It is classified according to blood gases values:

• Type 1 Respiratory Failure (hypoxemic): is associated with damage to lung tissue which prevents adequate oxygenation of the blood.  However, the remaining normal lung is still sufficient to excrete carbon dioxide. This results in low oxygen, and normal or low carbon dioxide levels.⁵ Arterial oxygen pressure (PaO₂) is <8 kPa (60 mm Hg) with normal or low arterial carbon dioxide pressure (PaCO₂).^6,7
• Type 2 Respiratory Failure (hypercapnic): occurs when alveolar ventilation is insufficient to excrete the carbon dioxide being produced. Inadequate ventilation is due to reduced ventilatory effort or inability to overcome increased resistance to ventilation. It affects the lung as a whole, and therefore carbon dioxide accumulates, presenting with PaO2 of <8 kPa (60 mm Hg) or normal, with hypercapnia PaCO2 >6.0kPa (> 50 mm Hg).^5,7

Causes of type 1 respiratory failure include: pulmonary oedema, pneumonia, COPD, asthma, acute respiratory distress syndrome, chronic pulmonary fibrosis, pneumothorax, pulmonary embolism, pulmonary hypertension.^5,7

Type 2 respiratory failure is commonly caused by COPD but may also be caused by chest-wall deformities, respiratory muscle weakness and Central nervous system depression (CNS depression.)⁵ CNS depression is associated with reduced respiratory drive and is often a side effect of sedatives and strong opioids. It may also be caused by severe asthma, myasthenia gravis, muscle disorders, obesity , hypothyroidism and adult respiratory syndrome.⁷

Once aware of individual risk factors, healthcare professionals are able to plan interventions that minimize risk and reduce the likelihood of increased morbidity and mortality.

Intervening in cases of respiratory failure includes not only supportive measures as well as treatment of the underlying cause.⁶ Depending on presentation, interventions aim to correct hypoxemia or hypercapnia and respiratory acidosis.

• Correction of hypoxemia: aim to maintain adequate oxygenation, achieved with an arterial oxygen pressure (PaO₂) of 60 mm Hg. The inspired oxygen concentration should be adjusted at the lowest level which is sufficient for tissue oxygenation.⁶ Oxygen can be delivered via nasal canula, simple face mask, nonrebreathing mask or high flow nasal canula. In severe cases, patient may require invasive ventilatory support.
• Correction of hypercapnia and respiratory acidosis: this is achieved by treating the underlying cause or providing ventilatory support.⁶

Type 1 and type 2 respiratory failure is a serious medical condition. Mortality associated with respiratory failure depends on the underlying cause as well as the speed of diagnosis and efficacy of management.⁷ Being able to prevent, detect and intervene adequately is crucial for improved patient outcomes.

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