Frequently patients with chronic obstructive pulmonary disease have lowered arterial
oxygen saturation in daytime. During sleep, they are apt to experience additional
hypoxemia. These episode of nocturnal hypoxemia are usually associated with periods of
relative hypoventilation. Noctunal hypoxemia may be associated with cardiac arrhythmia
and with acute increase in pulmonary arterial pressure and may be implicated in the
development of chronic pulmonary hypertension and cor pulmonale. We selected 14
patients with chronic obstructive pulmonary disease, 9 with emphysema dominant type
and 5 with chronic bronchitis dominant type, to examine the frequency and severity of
nocturnal hypoxemia and the effect of oxygen in prevention of nocturnal hypoxemia.
The results were as follows;
1) On PFT, FVC, FEV1 and FEV1/FVC showed no
significant difference between the emphysema dominant type (pink puffers, PP) and the
chronic bronchitis dominant type (blue bloaters, BB). But DLCO/VA for the PP group
was 45.7±15.1% which was significantely different from BB group, 82.4±5.6%.
2) The daytime arterial oxygen saturation (SaO2) and the lowest
SaO2 during sleep for the BB group were significantly lower than for the
PP group.
3) The hypoxemic episodes during sleep were more frequent in BB group and the
duration of hypoxemic episode was longer in BB group.
4) In both group studied, although there was a tendency for a lower
L-SaO2 (the lowest SaO2 during sleep), an increase in
hypoxemic episodes and duration as the daytime SaO2 fell lower, the only
parameter which showed significant correlation was daytime SaO2 and the
frequency of hypoxemic episodes in the PP group(r=-0.68, P<0.05).
5) In PP group, with oxygen supplementation, L-SaO2 during sleep
showed significant increase, and there was a tendency for the frequency of hypoxemic
episodes and duration to fall but it was not significant.
6) In BB group, oxygen supplementation significantly increased the
L-SaO2 during sleep and also significantly decreased the frequency and
duration of hypoxemic episode.
From these results, we can see that oxygen supplementation during sleep can prevent
the decrease in SaO2 to some extent and that this effect of oxygen can be
seen more prominently in the BB group.
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