Independent associations between arterial bicarbonate, apnea severity and hypertension in obstructive sleep apnea

Davoud Eskandari, Ding Zou, Ludger Grote, Hartmut Schneider, Thomas Penzel, Jan Hedner

Research output: Contribution to journalArticle

Abstract

Background: Obstructive sleep apnea is characterized by intermittent hypoxia and hypercapnia. CO2 production, transport and elimination are influenced by the carbonic anhydrase enzyme. We hypothesized that elevated standard bicarbonate, a proxy for increased carbonic anhydrase activity, is associated with apnea severity and higher blood pressure in patients with obstructive sleep apnea. Methods: A retrospective analysis of a sleep apnea cohort (n = 830) studied by ambulatory polygraphy. Office systolic/diastolic blood pressure, lung function, and arterial blood gases were assessed during daytime. Results: Arterial standard bicarbonate was increased with apnea severity (mild/moderate/severe 24.1 ± 1.8, 24.4 ± 1.7 and 24.9 ± 2.9 mmol/l, respectively, Kruskal-Wallis test p < 0.001). Standard bicarbonate was independently associated with apnea hypopnea index after adjustment for sex, age, body mass index, smoking, alcohol, hypertension, pO2 and pCO2 (standard bicarbonate quartile 1 vs. quartile 4, β = 10.6, p < 0.001). Log-transformed standard bicarbonate was associated with a diagnosis of hypertension or diastolic blood pressure but not systolic blood pressure adjusting for cofounders (p = 0.007, 0.048 and 0.45, respectively). Conclusions: There was an independent association between sleep apnea severity and arterial standard bicarbonate. The link between high standard bicarbonate and daytime hypertension suggests that carbonic anhydrase activity may constitute a novel mechanism for blood pressure regulation in sleep apnea.

Original languageEnglish (US)
Article number130
JournalRespiratory Research
Volume18
Issue number1
DOIs
StatePublished - Jun 28 2017

Fingerprint

Obstructive Sleep Apnea
Apnea
Bicarbonates
Blood Pressure
Hypertension
Carbonic Anhydrases
Sleep Apnea Syndromes
Hypercapnia
Proxy
Body Mass Index
Gases
Smoking
Alcohols
Lung
Enzymes

Keywords

  • Acid base
  • Blood pressure
  • Carbonic anhydrase
  • Hypercapnia
  • Obstructive sleep apnea

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

Cite this

Independent associations between arterial bicarbonate, apnea severity and hypertension in obstructive sleep apnea. / Eskandari, Davoud; Zou, Ding; Grote, Ludger; Schneider, Hartmut; Penzel, Thomas; Hedner, Jan.

In: Respiratory Research, Vol. 18, No. 1, 130, 28.06.2017.

Research output: Contribution to journalArticle

Eskandari, Davoud ; Zou, Ding ; Grote, Ludger ; Schneider, Hartmut ; Penzel, Thomas ; Hedner, Jan. / Independent associations between arterial bicarbonate, apnea severity and hypertension in obstructive sleep apnea. In: Respiratory Research. 2017 ; Vol. 18, No. 1.
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KW - Acid base

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