Abstract

The principal function of the lungs is to facilitate the exchange of O2 and CO2 between the air and the blood in the pulmonary capillaries. Achievement of this function is reflected by the maintenance of the partial pressures of these gases in systemic arterial blood in the normal ranges as 80-100 mmHg for PaO2 and 35-45 mmHg for PaCO2. These definitions are based on blood gas analyses in individuals breathing air at sea level, while at rest. Respiratory failure is a condition which the respiratory system fails in one or both of its gas-exchanging functions. There are many pulmonary and systemic diseases which cause respiratory failure. Hence, respiratory failure is a syndrome rather than a disease. Two types of respiratory failure (hypoxemic and hypercapnic) are recognized and both of them may be acute or chronic. In this article, the basic pathophysiological mechanisms of respiratory failure, clinical approach and indications of intensive care have been evaluated and the issue has taken a material form with some case reports.