| 1. |
- Becker, H. F., et al.
(författare)
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Effect of nasal continuous positive airway pressure treatment on blood pressure in patients with obstructive sleep apnea
- 2003
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Ingår i: Circulation. ; 107:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is increasing evidence that obstructive sleep apnea (OSA) is an independent risk factor for arterial hypertension. Because there are no controlled studies showing a substantial effect of nasal continuous positive airway pressure (nCPAP) therapy on hypertension in OSA, the impact of treatment on cardiovascular sequelae has been questioned altogether. Therefore, we studied the effect of nCPAP on arterial hypertension in patients with OSA. METHODS AND RESULTS: Sixty consecutive patients with moderate to severe OSA were randomly assigned to either effective or subtherapeutic nCPAP for 9 weeks on average. Nocturnal polysomnography and continuous noninvasive blood pressure recording for 19 hours was performed before and with treatment. Thirty two patients, 16 in each group, completed the study. Apneas and hypopneas were reduced by approximately 95% and 50% in the therapeutic and subtherapeutic groups, respectively. Mean arterial blood pressure decreased by 9.9+/-11.4 mm Hg with effective nCPAP treatment, whereas no relevant change occurred with subtherapeutic nCPAP (P=0.01). Mean, diastolic, and systolic blood pressures all decreased significantly by approximately 10 mm Hg, both at night and during the day. CONCLUSIONS: Effective nCPAP treatment in patients with moderate to severe OSA leads to a substantial reduction in both day and night arterial blood pressure. The fact that a 50% reduction in the apnea-hypopnea index did not result in a decrease in blood pressure emphasizes the importance of highly effective treatment. The drop in mean blood pressure by 10 mm Hg would be predicted to reduce coronary heart disease event risk by 37% and stroke risk by 56%.
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| 2. |
- Heitmann, J, et al.
(författare)
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Sympathetic activity is reduced by nCPAP in hypertensive obstructive sleep apnoea patients.
- 2004
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Ingår i: The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. - 0903-1936. ; 23:2, s. 255-62
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence that nasal continuous positive airway pressure (nCPAP) lowers blood pressure in obstructive sleep apnoea (OSA) patients, not only during sleep but also in the daytime. However, both the mechanisms of blood pressure reduction and the considerable differences in the magnitude of the effect in the studies presented to date are not fully understood. Therefore, the authors prospectively studied the effect of nCPAP on noradrenaline plasma levels (NApl), blood pressure and heart rate (HR) in 10 normotensive and eight hypertensive OSA patients before and after 41.6 +/- 16.9 days of nCPAP therapy. Polysomnography and invasive blood pressure were continuously monitored over 24 h in the supine position before and with nCPAP. NApl were analysed every 15 min. In hypertensives, nCPAP reduced NApl by 36 +/- 25%, lowered mean arterial blood pressure substantially (night-time: -8.89 +/- 14.09 mmHg; daytime: -7.94 +/- 10.47 mmHg) and decreased HR by 6.6 +/- 5.4 beats x min(-1), whereas in normotensives there were only minor changes. The decrease in heart rate was associated with a decrease in mean arterial blood pressure and noradrenaline plasma levels, suggesting a causal effect of nasal continuous positive airway pressure therapy. This nasal continuous positive airway pressure effect occurs mainly in hypertensive obstructive sleep apnoea patients, whereas the effect is small in normotensives. This may explain, at least in part, some of the discrepant results in previous treatment studies.
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