Further studies on the application of the compartmentalization/airlock concept to aircraft and spacecraft.

The effect of the application of the compartmentalization/airlock on accidental decompression was studied in conscious rats, mice, and guinea pigs. It was observed that in unprotected rats and mice, 78 of 102 middle ears (76.5%) exhibited hemorrhages with their eardrums intact; and in unprotected guinea pigs, 37 of 50 eardrums (74%) revealed rupture associated with hemorrhages of all middle ears (100%). Seven cases of malleus fractures (14%) were also found in unprotected guinea pigs. On the other hand, none of the protected animals showed signs of middle ear barotrauma. The protective effect on the tolerance of middle ears in the present study showed the same tendency as that on the tolerance of lungs in our previous study. These findings indicate that the application of the compartmentalization/airlock would be of great value in protection against accidental rapid decompression of pressurized aircraft and spacecraft.