Use of an acoustic helium analyzer for measuring lung volumes.

We have evaluated the use of an acoustic gas analyzer (AGA) for the measurement of total lung capacity (TLC) by single-breath helium dilution. The AGA has a rapid response time (0-90% response = 160 ms for 10% He), is linear for helium concentration of 0.1-10%, is stable over a wide range of ambient temperatures, and is small and portable.

Pseudo-internuclear oculomotor ophthalmoplegia secondary to Guillain-Barré polyneuronitis simulating myasthenia gravis in a air transport pilot.

A 32-year old experienced co-pilot was grounded because of handicapping and disabling doulbe vision and was off-flight from October, 1969, until January, 1972. He presented with a bilateral external ophthalmoplegia with alternate extreme divergent strabismus, and polyneuronitis. The clinical picture was confused by features resembling either a polyneuronitis of the Guillain-Barrè type, (confused by a false positive Tensilon test), myasthenia gravis, or a demyelinizing process.