The physiological dead space is decreased by

Dead space is defined as the volume of the airway that doesnot paicipate in gas exchange (It is nothing but ventilation occurs but perfusion doesnot occur) Anatomical Dead Space : from nasopharynx to respiratory bronchioles.average adult,normally 150ml Alveolar dead space : Alveoli that are ventilated but not perfused.usually it is absent Physiological or total dead space : Anatomical + Alveolar dead space Factors that increase dead space : upright position neck extension advanced age positive pressure ventilation decreased pulmonary perfusion (pulmonary emboli or pulmonary hypeension) lung diseases (emphysema or cystic fibrosis ) FACTORS THAT DECREASE DEAD SPACE : supine position , neck flexion , intubation Anatomical dead space is measured by single breath nitrogen test , physiological dead space is measured by modified bohr's equation.