Catheter was used to remove excess fluid from pleural space. it is necessary to drain air, secretions and blood from thoracic space in order to allow normal expansion of lungs. when surgeon places a catheter in the chest, they provide a drainage route that removes excess air and other body fluids that may build up. in some occasions two catheters are installed after surgery, one posteriorly and the other anteriorly. <span />
a system of physical units ( SI units ) based on the meter, kilogram, second, ampere, kelvin, candela, and mole, together with a set of prefixes to indicate multiplication or division by a power of ten.
