J'accuse!-M. LeComte de LaPlace a Prohibé le Recrutement des Alvéoles du Poumon

Abstract

A recurrent concept throughout all the natural sciences is that of capacitance—"the extension or displacement of a loaded structure per unit load." The electrical engineer knows capacitance as the ratio of charge/voltage. Physicists (since Hooke, who first enunciated the concept) recognize strain/stress as compressibility (the inverse of the modulus). Pulmonary physiologists look at volume/pressure and call it compliance, while biochemists view the volume of molecules that can be liganded to a carrier and call it a binding curve. Clinicians recognize this form as the oxygen-dissociation curve, instantly identified by its sigmoid shape. This shape also describes the inflation curve of the gasless lung—in the following sequence of increasing transpulmonary pressure: (1) a flat portion with only a small increase in volume—this segment describes the discontinuous openings of the smaller airways and alveoli, once their interfacial tensions have been overcome;