Nas. Taylor et Jb. Morrison, STATIC AND DYNAMIC PULMONARY COMPLIANCE DURING UPRIGHT IMMERSION, Acta Physiologica Scandinavica, 149(4), 1993, pp. 413-417
Elastic properties of the lung are typically assessed using the static
pressure-volume relaxation manoeuvre. Although dynamic methods have p
roduced equivalent results in normal healthy subjects, their use under
obstructive pulmonary disease states and during certain conditions ha
s been questioned. Static (C-st(1)) and dynamic (C-dyn(1)) pulmonary c
ompliance were measured in eight subjects in air (control) and during
C-dyn(1) decreased from 2.94 to 1.61 1 kPa(-1) following immersion, du
ring which subjects breathed air supplied at mouth pressure (P < 0.05)
, while C-st(1) remained approximately equivalent (3.16 and 4.07 1 kPa
(-1) respectively, P > 0.05). When immersed subjects were supplied wit
h breathing gas at lung centroid pressure (P-LC), C-dyn(1) returned to
control status (2.89 1 kPa(-1); P > 0.05), while C-dynm(1) remained s
table at 3.60 1 kPa(-1) (P > 0.05). The difference between C-st(1) and
C-dynm(1) may imply that flow-resistive properties are included withi
n the latter measurement. It is recommended that C-dyn(1), under these
conditions, be interpreted as an indes of peripheral airway patency,
rather than as an assessment of lung elasticity.