Footnotes for Chapter 4
1. Though AGOSTONI and FENN also used an esophageal balloon technique to measure pressure, their placement of the balloon led them to conclude that they were measuring alveolar pressure, not subglottal (tracheal). More exactly, the pressure presumably being measured was the intrathoracic pressure, which, when corrected for the properties of the lung, yielded alveolar pressure. This technique is discussed in detail by VAN DEN BERG (1956).