Respiratory Failure: Causes and Treatment

The lungs are responsible for the exchange of gas between the blood and air. Alveoli are microscopic air filled sacs present in the lung. Tiny blood vessels called capillaries are present in the wall of the alveoli. As the blood passes through the capillaries oxygen enters the blood from the alveoli and carbon dioxide enters the alveoli from the blood. Impairment of this exchange of gas may lead to a decrease in the level of oxygen in the blood or/and increase in the level of carbon dioxide in the blood. This disturbance in the level of oxygen and carbon dioxide in the blood leads to a condition called respiratory failure. Respiratory failure can be acute (sudden in onset) or chronic (present for a long time).

Causes of Respiratory Failure

Conditions that impair breathing can lead to respiratory failure. Breathing is the result of the synchronised activity of muscles, ribs, nerves, lungs and other supporting tissue. Damages to any of them may lead to impairment of gas exchange. Conditions that may lead to respiratory failure are:

Conditions affecting the lung

• Pneumonia.
• COPD
• ARDS
• Pulmonary embolism
• Cystic Fibrosis
• Inhalation of noxious substance

Diseases affecting muscle or muscle control

• Amyotrophic lateral sclerosis
• Muscular dystrophy
• Stroke
• Trauma to ribs
• Drug or alcohol overdose

Symptoms of Respiratory Failure

The symptoms seen in patients with respiratory failure are:

• Shortness of breath and air hunger
• Bluish nails and lips seen in severe cases where level of oxygen in blood is very low
• Loss of consciousness or a state of confusion
• Arrhythmia: irregular beating of heart, is seen when heart doesn’t get enough oxygen.

Diagnosis of Respiratory Failure

Your doctor will like to record a history of your symptoms. This will be followed by a physical examination where your doctor would like to hear for abnormal sound from your lungs with the help of stethoscope. Your doctor would also like to see your nails and tongue and lips, because a bluish colour on them is an indication that the level of oxygen in the body is low. Your doctor will then request for a few tests to confirm the diagnosis of respiratory failure. The tests are:

• Arterial blood gas analysis: a sample of blood is taken from an artery to measure the level of oxygen and carbon dioxide in the blood.
• Pulse oximetry: a small sensor attached to your ear or finger measures the oxygen level in the blood with the help of light.
• Chest X Ray: a picture of your chest taken with the help of x rays helps your doctor in identifying the cause of respiratory failure
• If your doctor suspects an arrhythmia on examination an electrocardiogram will be requested for too.

Treatment of Respiratory Failure

The treatment of respiratory failure has two goals; ensure enough oxygen reaches the blood and treat the underlying cause of respiratory failure.

• There are different methods of delivering oxygen to the body. The method used depends upon the severity of the disease:
• Oxygen therapy: air rich in oxygen is delivered to your nose via a two pronged nasal cannula or a mask
• Intubation: a tube, called an endotracheal tube, is introduced into the airway via your mouth to ensure that air reaches your lung. Before intubation you will be given a sedative and a muscle relaxant to prevent gagging while the endotracheal tube is being inserted. The tube is then connected to a ventilator which controls the flow of air into and out of the lungs.
• Tracheostomy: a tube is surgically introduced into your windpipe through the front of your neck, oxygen is delivered to your lungs via this tube
• Ventilator: a machine that delivers oxygen to and from your lungs. This method is reserved for patients who have severe respiratory failure.
• Non invasive positive pressure ventilation (NPPV): recommended for patients with chronic respiratory failure. This form of ventilation uses slight positive pressure to keep your airway open hence allowing patients with chronic respiratory failure to get better sleep.
• You will be given fluids through an IV line for nutrition and improvement of blood flow through the body.
• Medication to reduce discomfort.
• Once the cause of respiratory failure is identified your doctor will prescribe medication and suggest procedures to treat the same.

Resources

• https://www.nhlbi.nih.gov/health-topics/respiratory-failure
• https://bestpractice.bmj.com/topics/en-us/853