Influence of inflated lung pressure on lung mechanical properties during cold storage in rats.
The degree of lung inflation pressure during cold storage has a deep connection with lung functions after reperfusion. However, the change of the lung mechanical properties during cold storage at the different lung inflation pressure is unknown. We investigated the change of the mechanical properties both at the organ and the tissue level under different inflated lung pressure soon after the cold storage. In group I, the lungs were not preserved. In group II, the lungs were preserved in deflated condition. In groups III and IV, the lungs were inflated with room air at pressures of 14 and 25 cm H2O. After 24-hour storage, the input impedance (Z) was measured by a computer-controlled small animal ventilator (n = 8 each group). All data were analyzed using a homogeneous linear model, which includes airway resistance (R(aw)), tissue elastance (H), and tissue damping (G). Hysteresivity (eta) was calculated as G/H. After Z measurement, the tissue elasticity (Eqs) obtained from the quasi-static stress-strain curve was compared. We also analyzed the biochemical changes of surfactant in bronchoalveolar lavage (BAL) fluid. R(aw )was significantly lower in groups III and IV than in group I (p < 0.01). Hysteresivity (eta) was significantly lower in group IV than in groups I and III (p < 0.05). Eqs was significantly higher in groups III and IV than in groups I and II (p < 0.01). The total protein level in the BAL fluid of the preserved groups was significantly higher compared with group I (p < 0.01). We conclude that hyperinflated storage would deteriorate lung tissue mechanical properties.
Ikeyama
Kazuyuki
K
Department of Thoracic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Sakai
Hiroaki
H
Omasa
Mitsugu
M
Hamakawa
Hiroshi
H
Nakamura
Takayuki
T
Fujinaga
Takuji
T
Fukuse
Tatsuo
T
Wada
Hiromi
H
D000064:Acclimatization; D000818:Animals; D001696:Biomechanical Phenomena; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D003080:Cold Temperature; D017097:Electric Impedance; D008168:Lung / Q000502:physiology*; D008297:Male; D023421:Models, Animal; D009926:Organ Preservation; D010743:Phospholipids / Q000032:analysis; D011312:Pressure; D011506:Proteins / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical
D010743:Phospholipids; D011506:Proteins