ABSTRACT

In the 1950s, Robin and colleagues found that expired carbon dioxide tension rose by 10 mmHg during sleep in seven patients with ‘emphysema and chronic hypercapnia’ and that four of the seven had Cheyne Stokes respiration during sleep.1,2 In the early 1960s, studies using an

early ear oximeter showed that arterial oxygen saturation fell during sleep in all the COPD patients, and the authors noted that the lowest oxygen saturations during sleep were recorded in those whose saturations were also lowest when awake.3 All this was reported before the sleep apnea syndrome was recognized4 in 1966. However, the great interest in breathing during sleep stimulated by the sleep apnea syndrome has resulted in increased attention

1am

2am 3am Time

4am 5am 6am

O xy

ge n

sa tu

ra ti

on (%

)

REM sleep

Awake Dense EM

O xy

ge n

sa tu

ra ti

on (%

)

No EM

92 Mean SEM in 18 patients

P 0.05 P 0.05} }

In REM sleep

being paid to breathing and oxygenation during sleep in patients with COPD.