Læknablaðið - 15.11.1987, Page 36

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LÆKNABLAÐIÐ
NÝR DOKTOR í LÆKNISFRÆÐI - ÞÓRARINN GÍSLASON
Nýlega varði Þórarinn
Gíslason doktorsritgerð
sína við Háskólann í
Uppsölum. Heiti
hennar er: Sleep apnea.
Eipidemiological,
clinical and ventilatory
aspects. Útdráttur
ritgerðarinnar fer hér
á eftir:
The sleep apnea syndrome (SAS) is characterized
by repeated apneic episodes and snoring during
sleep together with daytime sleepiness. The
prevalence of SAS was estimated by a two-stage
procedure. First 4064 questionnaries were posted
to men in the age group 30-69 years old, and after
two reminders an almost 80% response rate was
achieved. In the second stage a subgroup of 166
men who had reported the most pronounced
snoring and daytime sleepiness was selected and
eventually 61 of these came for whole-night
polysomnographic studies. Fifteen of them were
found to have 30 or more apneas and hypopneas,
and thus the lower prevalence of SAS was
estimated at 15/61 x 166/3100, or 1.3%, with a
standard error of 0.3%. The majority (53%) of
the SAS subjects were in the age group 50-59
years.
Heavy habitual snoring was reported by 15.5% of
the responders. This increased with age up to 60
years, but multiple regression analysis showed
that it was mainly correlated to the degree of
overweight. Among the hypertensives 21.5% were
habitual snorers, compared with 14.9% of the
remainders, but the hypertensives were also older
and more overweight. There was a statistically
significant overrepresentation of habitual snorers
among hypertensives of ages 40-49 years, even
within the same weight groups.
Excessive daytime sleepiness was reported by
5.7% of the men. Insomnia was also frequently
reported - both difficulties in falling asleep
(6.9%) and difficulties in maintaining sleep
(7.5%). The above complaints were all nearly
twice as common among those attending regular
medical check-ups for somatic diseases.
The accuracy and usefulness of transcutaneous
(tc) CO, measurements was studied in comparison
with arterial and end-tidal measurements, during
C02 rebreathing. PtcC02 responded more slowly
to both increases and decreases in PCO, than
PaC02, but otherwise showed similar values.
During sleep PlcC02 tracings proved useful for
detecting C02 retention, both in SAS and in
central hypoventilation.
The possible ventilatory effect of CNS
endorphins was tested by measuring CSF
endorphins in 15 SAS patients and comparing the
values with those of controls. The CSF level of
Fraction I endorphins (mean ± SD) was
significantly higher in SAS patients (3.0 ± 1.5
pmol/ml) than in controls (1.1 ± 0.5 pmol/ml).
There was a decrease in this level six months
postoperatively in successfully treated patients
and in some cases a simultaneous increase in
ventilatory responsiveness to C02.