Respiratory failure can be acute or chronic.

1. Chronic Respiratory Failure: Chronic respiratory failure is a long-term ongoing condition which can be resulted due to chronic respiratory diseases such as Chronic obstructive pulmonary disease (COPD) and Asthma. It generally occurs when the airways become too narrow and cannot carry air to your lungs. This leads to low oxygen levels in your blood. It is divided into two types:

• Hypoxemic respiratory failure (Hypoxemia): Hypoxemia or Interstitial Lung disease or Post tuberculosis destroyed lung is defined as a low level of oxygen in the blood but normal or close to normal levels of carbon dioxide in the blood (PaO2 < 60mmHg) also called type IRF.

• Hypercapnic respiratory failure (Hypercapnia): Hypercapnia is defined as a disability of the respiratory system to remove carbon dioxide from your blood. It is also called type II RF and is always associated with type I RF

2. Acute Respiratory Failure: Acute respiratory failure occurs suddenly and is a short-term condition. Generally treated in a medical emergency. 

Causes of respiratory failure: 

Obstructive airway diseases and restrictive patterns are distinct classifications of respiratory conditions. Respiratory failure can also be categorised into diseases involving the airways (obstructive) and those affecting the lung parenchyma or vasculature (restrictive). Long-term respiratory conditions such as asthma and COPD can lead to respiratory failure. 

Below are the common conditions that may lead to chronic respiratory failure: 

• Smoking:

Smoking is the cause of 90% of COPD cases. Cigarette smoke contains tobacco, which irritates the airways, causing inflammation and swelling that constricts the airways. Smoke also damages the cilia, making them unable to do their job, which is to remove trapped particles and accumulated mucus from the airways. 

• COPD:

Untreated COPD can lead to severe bacterial and viral infections and, eventually, respiratory failure.

• Other causes:

1. Obstructive lung disease

   • BA, ABPA, Cystic fibrosis

   • COPD

   • Bronchiectasis

   • Post TB  Sequalae

2. Restrictive Lung disease

   • ILDC (Various types)

   • Vascular disease

   • PAF

   • Muscular Dystrophy

   • Chest wall deformities

What are the signs and symptoms of chronic respiratory failure?

With the progression of the disease, the following symptoms may be experienced:

1. Shortness of breath while performing usual daily activities

2. Wheezing

3. Cough for a longer period than normal

4. More and more difficulty in breathing 

5. Weight loss

6. Frequent respiratory infections 

7. Chest tightness

8. Fatigue

9. Anxiety 

10. Headache 

11. Confusion

12. Skin, lips and nails turning blue

13. The worsening condition can lead to coma and even death 

Tests for diagnosis:

• Medical history with the following:

• Habit of smoking 

• Frequent exposure to secondary smoke

• Long-term exposure to air pollutants or toxins

• Physical exam and other tests:

1. Spirometry: It is conducted by your doctor to know the working conditions of your lungs

2. Pulse oximetry: To measure the amount of oxygen saturation in your blood

3. Arterial blood gas test: Easy procedure to measure oxygen, pH and acid content in your blood.

4. Chest Disease - Chest X-ray: Imaging tests for chest

5. HRCT chest - High-resolution completed tomography of chest

6. Bronchoscopy: It is done by entering a thin and lighted instrument into the lungs and airways to get a closer look.

7. Electrocardiogram: To check heart function

8. Exercise testing: To estimate the amount of oxygen drop in blood while exercising 

Management and treatment of chronic respiratory failure:

Inhaled therapy like nebulisers/ inhalers is the main therapy for airways.

 There are three main treatment options:

1. Treating the underlying cause of respiratory failure through medicines and other agents:

such as antibiotics: People with COPD are more susceptible to severe bacterial infections. Some antibiotics are prescribed to control and prevent infections. Examples; azithromycin, clarithromycin, cefuroxime, cefpodoxime, and cefdinir.

2. Supplementary Oxygen: In case of hypoxemia, a portable oxygen tank may be provided to improve oxygen levels (LTOT or short burst oxygen therapy).

3. Anticholinergics: These drugs relax the muscles which help release mucus and clear the airways. These agents may increase cough. Examples; ipratropium, tiotropium, revefenacin, and aclidinium.

4. Bronchodilators: It helps in breathing by the relaxation of smooth muscles. Example; albuterol, levalbuterol.

5. Anti-inflammatory drugs: Used to reduce swelling and inflammation. Corticosteroids such as mometrasone, budesonide, beclomethasone, fluticasone propionate.

6. Other agents: Expectorants are given to ease out the coughing, antivirals may be prescribed in case of viral infections such as influenza, and antihistamines such as cetirizine and levocetirizine are prescribed to relieve symptoms such as stuffy head.

7. Increasing oxygen levels: Oxygen levels are increased by providing oxygen through an oxygen concentrator or cylinder which enters in lungs through a face mask, nasal tubes or windpipe.

8. Positive Pressure Ventilation: Either NIPPY (Non Invasive Positive Pressure Ventilation)  or mechanical ventilation

Lifestyle changes that can help improve the respiratory system:

1. Eat a healthy diet

2. Gentle exercise

3. Lose weight

4. Reduce intake of alcohol

5. Quit smoking

6. Manage stress

7. Get better sleep

Conlusion:

Chronic respiratory failure is a condition that causes an inability to exchange carbon dioxide and oxygen effectively, resulting in chronically low oxygen levels or chronically high carbon dioxide levels.