|
|
||||||||
1 Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, and 2 Physiology Program, Harvard School of Public Health, Boston, Massachusetts 02115
The pressure-volume (P-V) characteristics of the lung microcirculation are important determinants of the pattern of pulmonary perfusion and of red and white cell transit times. Using diffuse light scattering, we measured capillary P-V loops in seven excised perfused dog lobes at four lung volumes, from functional residual capacity (FRC) to total lung capacity (TLC), over a wide range of vascular transmural pressures (Ptm). At Ptm 5 cmH2O, specific compliance of the microvasculature was 8.6%/cmH2O near FRC, decreasing to 2.7%/cmH2O as lung volume increased to TLC. At low lung volumes, the vasculature showed signs of strain stiffening (specific compliance fell as Ptm rose), but stiffening decreased as lung volume increased and was essentially absent at TLC. The P-V loops were smooth without sharp transitions, consistent with vascular distension as the primary mode of changes in vascular volume with changes in Ptm. Hysteresis was small (0.013) at all lung volumes, suggesting that, although surface tension may set basal capillary shape, it does not strongly affect capillary compliance.
capillary; diffuse light scattering; transit time; dog; hysteresis; mechanics
This article has been cited by other articles:
![]() |
J. P. Butler, R. E. Brown, D. Stamenovic, J. P. Morris, and G. P. Topulos Effect of surface tension on alveolar surface area J Appl Physiol, September 1, 2002; 93(3): 1015 - 1022. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. P. Topulos, R. E. Brown, and J. P. Butler Increased surface tension decreases pulmonary capillary volume and compliance J Appl Physiol, September 1, 2002; 93(3): 1023 - 1029. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |