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Respiratory failure

Management of acute respiratory failure

There are two components to the management of respiratory failure: emergency management (resuscitation), and definitive diagnosis and treatment of the underlying condition.

Emergency management

As always, this commences with an assessment of ABCDE. This approach is detailed elsewhere in this induction programme and most doctors will be very familiar with its principles. Make sure the airway is patent and protected, examine the patient and deal with life threatening emergencies. Gain i.v. access. Think about fluid therapy.

How much oxygen?

The simple answer to this is ‘enough’. If the SpO2 is normal, oxygen is not required.

If the SpO2 is low, then high flow oxygen in the short term will do little harm. It should be titrated quickly downwards using SpO2 as a guide. Aim for SpO2 of 92%.

In very few patients (those with clinically severe COPD who have compensated type II respiratory failure – a high bicarbonate with a high CO2) oxygen should be titrated upwards carefully with regular checks of the clinical status (mental state, ventilatory pattern) and blood gases (is CO2 rising?). These patients may hypoventilate when given too much oxygen. This may cause a respiatory arrest in severe circumstances, but more commonly will lead to profound hypoxaemia. This occurs when the FiO2 is reduced following a rise in CO2 (the hypoxia from the reduced FiO2 exacerbated by the high alveolar CO2).

In these patients, aim for SpO2 of 88 –92%. Always assess the response of the patient to your intervention: e.g. has the SpO2 increased, has the CO2 increased?

Definitive diagnosis and treatment

Respiratory failure is NOT an adequate diagnosis. It is a description of a condition that results from many underlying disorders. It is impossible to properly direct further investigation and treatment without a diagnosis. Treatment of the underlying problem is beyond the scope of this review but thought should be given to diseases listed in the table below.

 

Common

Exacerbation of COPD

LVF

Community Acquired Pneumonia/Hospital Acquired Pneumonia

Acute asthma

Drug overdose

ARDS/ALI

Reduced GCS

Atelectasis

Abdominal splinting

Pulmonary embolus

Pneumothorax

 

less common

 

 

 

 

 

Valvular heart disease

Interstitial Lung Disease (e.g. acute interstitial pneumonitis, drug induced pneumonitis, pulmonary fibrosis)

Extrinsic allergic alveolitis

Pulmonary haemorrhage

Organising Pneumonia

Fat emboli

Some causes of respiratory failure.

We will now discuss ARDS further.

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