Effect of added dead space on sleep disordered breathing at high altitude

Comparison of Sleep Disorders between Real and Simulated 3,450-m Altitude

“…The increase in sleep-disordered breathing observed in HH compared to NH is, however, more difficult to explain. The possible increase in physiological dead space in HH is probably not the only cause because previous studies by our group and others showed that an increase in dead space (using a face mask) could significantly decrease altitude-induced central respiratory events 43,44 (even though this experimental increase in dead space was probably much larger). Altered environmental conditions (comfort, temperature) at high altitude compared with simulated altitude could play a role but the arousal index was not different between both conditions.…”

Dead Space Mask Eliminates Central Apnea at Altitude

“…His five subjects with AHI > 30 all had significant reduction in AHI (Lovis et al, 2012). Our suspicion, similar to Lovis, was that dead space would stabilize periodic breathing by raising Pco 2 , thus keeping the Pco 2 farther from the apnea threshold (i.e., by increasing the CO 2 reserve).…”

“…To determine whether a dead space mask could be useful for decreasing insomnia, fatigue, AMS, or mood and cognition changes at altitude (Lemos et al, 2012) would, as Lovis concluded, require a large cohort and longer duration of successive nights at altitude (Lovis et al, 2012). Perhaps some of the arousals and complaints of poor sleep using the mask were discomfort related and would be expected to decrease with successive nights.…”

Sightings edited by John W. Severinghaus

“…In the 5 with severe sleep problems, dead space reduced AHI from 70 to 29 and ODI from 73 to 42 per hour whereas it had no significant effect in the second group. Microarousal index, sleep efficiency, and sleep architecture remained unchanged by dead space (Lovis et al, 2012).…”