Intensive care ventilator is indicated when the patient's spontaneous respiration is inadequate to maintain life. It is also indicated as prophylaxis for imminent collapse of other physiologic functions, or ineffective gas exchange in the lungs. Because intensive care ventilator serves only to provide assistance for breathing and does not cure a disease, the patient's underlying condition should be correctable and should resolve over time. In addition, other factors must be taken into consideration because intensive care ventilator is not without its complications (see below)

Common medical indications for use include:

 Acute lung injury (including ARDS, trauma)

 Apnea with respiratory arrest, including cases from intoxication

 Chronic obstructive pulmonary disease (COPD)

 Acute respiratory acidosis with partial pressure of carbon dioxide (pCO2) > 50 mmHg and pH <7.25,which may be due to paralysis of the diaphragm due to Guillain-Barre syndrome, myasthenia gravis, spinal cord injury, or the effect of anaesthetic and muscle relaxant drugs

 Increased work of breathing as evidenced by significant tachypnea, retractions, and other physical signs of respiratory distress

 Hypoxemia with arterial partial pressure of oxygen (PaO2) < 55 mm Hg with supplemental fraction of inspired oxygen (FiO2) = 1.0

 Hypotension including sepsis, shock,  congestive heart failure

 Neurological diseases such as muscular dystrophy and amyotrophic lateral sclerosis.