Effects of hyperventilation in vivo on lung pressure-volume curves
Akashiba, T.; Enomoto, S.; Ishida, J.; Inazawa, T.; Nagao, K.; Horie, T.; Okayasu, M.
Nihon Kyobu Shikkan Gakkai Zasshi 18(3): 141-146
1980
ISSN/ISBN: 0301-1542 PMID: 7392317 Document Number: 161041
Artificial ventilation causes signficant elevation of elastic recoil. To study changes in pressure-volume (P-V) curves after artifical ventilation. Rabbits (5) were ventilated as controls and 20 were ventilated with a tidal volume of 60-70% TLC for 3 h with an end-expiratory pressure (EEP) of 0 cm H2O (EEP: 0, 10 cases) and with EEP: 2 cm H2O (10 cases). After ventilation arterial blood was obtained and the lungs were excised following exsanguination and P-V curves were recorded by a body plethysmograph with air. Then saline P-V curves wer recorded with 2 control lungs and 3 lungs of each ventilated group. Others were used for the measurement of the wet and dry weight ratio. Ventilated lungs with EEP of 0 cm H2O showed significantly higher elastic recoil with air than controls and ventilated lungs with EEP of 2 cm H2O. Ventilated lungs with EEP of 2 cm H2O also showed higher elastic recoil with air than controls but the difference was not singificantly statistically. Saline P-V curves showed no remarkable differences in each group. The wet dry ratio was signficantly elevated in ventilated lungs with EEP of 0 cm H2O compared to those of controls and ventilated lungs with EEP of 2 cm H2O. Artificial ventilation performed at low lung volume with large tidal volume may cause the alteration in surface forces; this may be partially due to lung edema formation.