Figure 2 - uploaded by Raichel M. Alex
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Blood Pressure Variations during Apnea. (a) Intermittent BH Maneuvers in Supine A. BH segments are marked by red dotted line. (b) Overnight Polysomnography. Note the significant oscillations in BP along with reduction in SaO2 saturation. Patterns are similar in both BH maneuvers and OSA episodes.
Contexts in source publication
Context 1
... panels of (Figure 2a) show an example of BH-induced elevation of BP. Detectable and fairly repeatable BP elevation during all five BH episodes, followed by recovery to baseline during inter-BH intervals was observed in both protocols during supine and sitting posture. ...
Context 2
... and fairly repeatable BP elevation during all five BH episodes, followed by recovery to baseline during inter-BH intervals was observed in both protocols during supine and sitting posture. (Figure 2b) b) Effect of Apnea Frequency: During K-S test, Area (p=0.02), Systole (p=0.015) and Dias lope (p=0.021) in supine posture, and BH duration (p=0.034) in sitting posture did not follow Gaussian distribution, requiring data transformation and outlier removal with Mean±2SD as threshold. ...
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Citations
... Our prior investigations of nocturnal BP dynamics in OSA patients documented that for almost every obstructive event, the OSA patient experiences a significant surge in BP [21][22][23]. Since OSA patients experience numerous obstructive apnea and hypopnea events during sleep, their cardiovascular system is subjected to significant BP oscillations. Hence, quantifying these oscillations for the whole night is of interest. ...
Obstructive sleep apnea (OSA) pathologically stresses the cardiovascular system. Apneic events cause significant oscillatory surges in nocturnal blood pressure (BP). Trajectories of these surges vary widely. This variability challenges the quantification, characterization, and mathematical modeling of BP surge dynamics. We present a method of aggregating trajectories of apnea-induced BP surges using a sample-by-sample averaging of continuously recorded BP. We applied the method to recordings of overnight BP (average total sleep time: 4.77 ± 1.64 h) for 10 OSA patients (mean AHI: 63.5 events/h; range: 18.3-105.4). We studied surges in blood pressure due to obstructive respiratory events separated from other such events by at least 30 s (274 total events). These events increased systolic (SBP) and diastolic (DBP) BP by 19 ± 7.1 mmHg (14.8%) and 11 ± 5.6 mmHg (15.5%), respectively, relative to mean values during wakefulness. Further, aggregated SBP and DBP peaks occurred on average 9 s and 9.5 s after apnea events, respectively. Interestingly, the amplitude of the SBP and DBP peaks varied across sleep stages, with mean peak ranging from 128.8 ± 12.4 to 166.1 ± 15.5 mmHg for SBP and from 63.1 ± 8.2 to 84.2 ± 9.4 mmHg for DBP. The aggregation method provides a high level of granularity in quantifying BP oscillations from OSA events and may be useful in modeling autonomic nervous system responses to OSA-induced stresses.
... Moreover, the increased variation in nocturnal blood pressure is a characteristic of nocturnal hypertension in OSA patients [6]. Such a phenomenon is due to a temporary increase in arterial stiffness resulting from sympathetically mediated vasoconstriction, or increased cardiac stroke volume driven by isotropic effects of sympathoexcitation, or both [7]. Our group as well as others have reported highly repetitive and significant surges in BP during apnea in OSA patients. ...
We present an approach to quantifying nocturnal blood pressure (BP) variations that are elicited by sleep disordered breathing (SDB). A sample-by-sample aggregation of the dynamic BP variations during normal breathing and BP oscillations prompted by apnea episodes is performed. This approach facilitates visualization and analysis of BP oscillations. Preliminary results from analysis of a full night study of 7 SDB subjects (5 Male 2 Female, 52±5.6 yrs., Body Mass Index 36.4±7.4 kg/m2, Apnea-Hypopnea Index 69.1±26.8) are presented. Aggregate trajectory and quantitative values for changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) concomitant with obstructive apnea episodes are presented. The results show 19.4 mmHg (15.3%) surge in SBP and 9.4 mmHg (13.6%) surge in DBP compared to their respective values during normal breathing (p<0.05). Further, the peak of the surge in SBP and DBP occurred about 9s and 7s, respectively, post the end of apnea events. The return of SBP and DBP to baseline values displays a decaying oscillatory pattern.
