BiPAP-ST (Spontaneous Timed)therapy is used in the treatment of COPD(chronic obstructive pulmonary disease) . BiPAP-ST machine includes machine, humidifier,tubing and mask.BiPAP-ST machine is very easy to use. BiPAP-ST machine helps to keep open airways open while the person is sleeping, making it easier to breathe by exchange of oxygen with carbon dioxide .rnIt gives a higher level of pressure every time a spontaneous breath is taken, followed by a lower level of pressure during exhalation.