Mechanical ventilation in the term used for assisted ventilation where oxygen is supplied to the lungs by means of artificial ways. It is done in cases when the person is unable to breath on his own. There are two main types of mechanical ventilation: 1. Positive pressure ventilation 2. Negative pressure ventilation It can be used for: Short period- In respiratory assistance in surgeries Long periods- Critical patients For home use in people with breathing difficulties INDICATIONS OF MECHANICAL VENTILATION Ventilatory indications: 1. Decreased respiratory drive 2. Abnormalities of chest wall 3. Respiratory muscle fatigue 4. Neuromuscular disease 5. Hypotension 6. Respiratory arrest with apnea 7. Comatose patients Inefficient or insufficient gas exchange: 1. Intrapulmonary shunt 2. Ventilation-perfusion mismatch 3. Decreased FRC 4. Vital capacity <15 mL/kg