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).
PiP (the pressure outside the lungs) is not uniformly distributed. It is smaller at the base than the apex of the lung. A cause for this difference is the weight of the lung, which would result in a stronger pull from the chest wall at the apex.