SYSTEMIC BLOOD-PRESSURE ELEVATION AFTER AIRWAY OCCLUSION DURING NREM SLEEP

Citation
J. Ringler et al., SYSTEMIC BLOOD-PRESSURE ELEVATION AFTER AIRWAY OCCLUSION DURING NREM SLEEP, American journal of respiratory and critical care medicine, 150(4), 1994, pp. 1062-1066
Citations number
22
Categorie Soggetti
Emergency Medicine & Critical Care","Respiratory System
ISSN journal
1073449X
Volume
150
Issue
4
Year of publication
1994
Pages
1062 - 1066
Database
ISI
SICI code
1073-449X(1994)150:4<1062:SBEAAO>2.0.ZU;2-M
Abstract
Increases in arterial pressure follow obstructive sleep apneas even in the absence of hypoxemia. These blood pressure (BP) elevations could be caused by arousal from sleep, resumption of ventilation, or abrupt changes of intrathoracic pressure (ITP). To better define the relative contributions of each of these factors to the BP elevations, we desig ned two protocols employing six normal subjects isolating the effects of arousal from those of ventilation and ITP. BP (Penaz method), sleep stage, air flow, and esophageal pressure (Pes) were monitored. Episod ically, a stopcock was closed, occluding the inspiratory circuit. In E xperiment 1, data were recorded on tape. Occlusions were initiated dur ing Stage 2 NREM sleep and released coincident with arousal. Subjects were than awakened and instructed to trace the displayed, taped Pes pr ofile creating occulsions of identical duration to those recorded duri ng sleep. In five subjects, the mean BP elevation (preocclusion to pea k) associated with occlusion release upon arousal was 19.0 +/- 5.1 mm Hg, whereas the analogous rise for matched awake occlusions was 5.4 +/ - 4.8 mm Hg (p = 0.027). In Experiment 2, occlusion release was delaye d 6 to 12 s after arousal. In five subjects, these occlusions were ass ociated with BP elevations that peaked coincident with arousal, not wi th resumption of ventilation (mean increase, 18.0 +/- 10.4 mm Hg). We conclude that under the conditions of these experiments, BP elevations after airway occlusion during sleep are attributable more to arousal than to resumption of ventilation.