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Exponential analysis of the lung pressure‐volume curve in newborn mammals
Author(s) -
Saetta Marina,
Mortola Jacopo P.
Publication year - 1985
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950010405
Subject(s) - lung volumes , lung , pulmonary compliance , medicine , transpulmonary pressure , lung function , volume (thermodynamics) , cardiology , anatomy , thermodynamics , physics
Abstract The compliance of the lung (per unit of lung weight) is less in newborn mammals than in adults. This could result from a smaller volume of airspaces per unit weight and/or a lower lung distensibility. The isolated role of lung distensibility was evaluated by using a mathematical description of the pressure‐volume (P‐V) curve during lung deflation. Deflation limbs of static P‐V curves in newborns of six species (four experimentally obtained and two taken from the literature) ranging from total lung capacity to the resting volume (V r ) were fitted by a monoexponential function of the type V = B − Ae −KP , where B equals V max at infinite P, A equals the difference between V max and V at P = O, and K is a constant representing lung distensibility. Unlike in adults, in newborns the monoexponential fitting provided an adequate description of the P‐V curve for only a relatively small range of transpulmonary pressure (from P at V r to 10–15 cm H 2 O). The K value of this portion of the curve was similar among species but higher than in adult mammals, averaging 0.240 cm H 2 O −1 . This suggests a similar lung structure in the different species. Since lung distensibility in newborns is larger than in adults, the fact that a unit mass of lung in the newborn is less compliant should be due to the smaller volume of its airspaces.