types of respiratory failure? Flashcards
what is resp failure?
Respiratory failure leads to a decrease in the partial pressure of oxygen in the blood due to inadequate ventilation or poor perfusion.
what is type 1 resp failure?
Low PaO2 (<8kPa) with or without low PaCO2.
what causes type.1 resp failure?
Decreased atmospheric pressure
Ventilation-perfusion mismatch
Shunt
Pneumonia
ARDS
Pulmonary embolism
pathophysiology of type 1 resp failure?
The damage in lung tissues limits blood oxygenation, resulting in hypoxaemia and hypoxia, but the normal lung tissues that remained are still able to sustain carbon dioxide excretion.
how do you ix type 1 resp failure?
An accurate measurement of PaO2 and diagnosis of type 1 respiratory failure requires arterial blood gas sampling, which can be painful. Alternatively, a pulse oximeter can be used instead of repeated arterial blood gas sampling.
how do you tx type 1 resp failure?
Initial treatment of type 1 respiratory failure is prescribing supplemental oxygen or continuous positive airway pressure (CPAP) ventilation and correcting the underlying cause.
If the patient is on supplementary O2, PaO2 may be normal, but inappropriately low for the fraction of inspired oxygen (FiO2).
what is type 2 resp failure?
Type 2 respiratory failure, also known as hypercapnic respiratory failure, is defined as high arterial partial pressure of carbon dioxide (PaCO2) and low arterial partial pressure of oxygen (PaO2).
PaCO2 is >6kPa, while PaO2 is <8kPa.
pathophysiology of type 2 resp failure?
It is due to inadequate alveolar ventilation, resulting in impaired ability to excrete carbon dioxide.
In contrast to type 1 respiratory failure, the inadequate alveolar ventilation in type 2 respiratory failure typically occurs due to failure in respiratory pump and increased ventilatory resistance of the entire lungs, not just an area of lung tissues.
causes of type 2 resp failure?
Chronic obstructive pulmonary disease (COPD)
Chest wall deformities such as kyphosis or scoliosis
Central nervous system depression due to opioids or sedatives
Severe asthma
Myasthenia gravis
Guillain-Barre syndrome
Obesity
Respiratory distress syndrome
Hypercapnia as a result of respiratory acidosis is potentially fatal.
features of type 2 resp failure?
Headache
Altered level of consciousness
Warm extremities
Behavioural change
Asterixis
Papilloedema
ix for type 2 resp failure?
Arterial blood gas: PaCO2 >6kPa, PaO2 <8kPa for the diagnosis of type 2 respiratory failure
Pulse oximetry: measure oxygen saturation (SpO2)
Simple spirometry: measure tidal volume and vital capacity
Electrocardiogram: look for cardiac arrhythmias secondary to hypoxaemia and acidosis
management type 2?
Treat the underlying pathology
Supplemental oxygen via a nasal canula, a face mask, a venturi mask or a non-rebreather mask
Non-invasive ventilation such as a Continuous Positive Airway Pressure (CPAP) ventilation or a Bilevel Positive Airway Pressure (BiPAP) ventilation
Invasive mechanical ventilation via an endotracheal tube or a tracheostomy
