Speaking roughly, normal levels of thyroid-stimulating hormone (TSH) are in the range of 0.4 to 4.0 mIU/L. However, each laboratory and test manufacturer identifies its own normal TSH range.
This pressure is typically set slightly higher than atmospheric pressure to prevent atelectasis, decrease inspiratory work of breathing, or improve gas exchange depending on the clinical scenario. This positive end-expiratory pressure (PEEP) is generated by a resistor in the exhalation port of the ventilator (Fig. 2).
The main difference between CPAP and VPAP machines is that while a CPAP machine delivers a constant air pressure, The VPAP machine delivers two sets of air pressure - one for inhaling and another for exhaling.