Objective There is an unmet need for noninvasive continuous blood pressure (BP) monitoring technologies in various clinical settings. Continuous and noninvasive central aortic BP monitoring is technically not feasible currently, but if realized, would provide more accurate and real-time global hemodynamic information than any form of peripheral arterial BP monitoring in an acute care setting. As part of our efforts to develop such, herein we examined the tracking correlation between noninvasivelyderived peripheral arterial BP by Caretaker device against invasively measured central aortic BP.Methods Beat-to-beat BP by Caretaker was recorded simultaneously with central aortic BP measured in patients undergoing cardiac catheterization. Pearson's correlation was also derived for SBP and DBP. A trend comparison analysis of the beat-to-beat BP change was performed using a four-quadrant plot analysis with the exclusion zones of 0.5 mmHg/s to determine concordance, (i.e. the direction of beat-to-beat changes in SBP and DBP).Results A total of 47 patients were included in the study. A total of 31 369 beats representing an average of 17.3 min of recording were used for analysis. The trend analysis yielded concordances of 84.4 and 83.5% for SBP and DBP, respectively. Respective correlations (Pearson's r) for SBP and DBP trends were 0.87 and 0.86 (P < 0.01). Tracking of beat-to-beat BP by Caretaker showed excellent concordance and correlation in the direction and the degree of BP change with central aortic BP, respectively. ConclusionThis study supports the satisfactory performance of the Caretaker device in continuous tracking of central aortic BP beat-to-beat BP and provides a basis to develop an algorithm for absolute central aortic BP estimation in the future.

Background: Obstructive sleep apnoea (OSA) episode related blood pressure (BP) surge may mediate the association of OSA with cardiovascular disease. However, BP is not measured during a clinical sleep study. Method:We tested the feasibility of incorporating the Caretaker physiological monitor, which utilizes a novel continuous beat-to-beat (b-b) BP monitoring technology, into polysomnography (PSG) and aimed to characterize BP surges related to obstructive respiratory events. B-b BP was concurrently collected and merged with PSG data on a posthoc basis. We compared BP surge between mean respiratory (apnoea, hypopnea and desaturation-alone events) and nonrespiratory events (spontaneous or leg movement-related arousals). We examined the association of the degree of oxygen desaturation with BP surge in a given respiratory event combining all events. A total of 17 consecutive patients (12 men, mean 52 years old, nine diagnostic and eight split-night PSGs) undergoing clinically indicated PSG were included after excluding one patient with poor signal quality due to excessive movement.Results: Caretaker was well tolerated. Mean respiratory BP surge ranged from 5 to 19 mmHg [Median (IQR) ¼ 13.9 (9.5-16.2)]. Mean BP surge between the respiratory and nonrespiratory events was similar [13.8 (4.5) vs. 14.9 (5.3) mmHg, P ¼ 0.13]. Accounting for the count distribution of desaturation/BP surge data pair events, there was a linear correlation between the degree of oxygen desaturation and BP surge (R ¼ 0.57, P < 0.001). In eight patients undergoing split-night sleep studies, the number of BP surge events (10 mmHg/h) decreased during continuous positive airway pressure in all but one patient. Conclusion:We demonstrated highly variable OSA-related BP surge patterns using the Caretaker's b-b BP monitoring technology that has the potential to be integrated into sleep studies.

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Introduction Children with Down Syndrome (DS) are at high risk of sleep disordered breathing (SDB). Undiagnosed SDB in younger children may confer further risks of cardiovascular and neurocognitive complications associated with DS. However, there is paucity of studies examining SDB in infants with DS. The purpose of the study was to examine the prevalence of obstructive sleep apnea (OSA), sleep hypoventilation (SH) and hypoxemia in infants with DS. Methods Infants (≤12 months old) with DS who underwent first polysomnography (PSG) at Seattle Children’s hospital over a 6-year period were included. Data collected included obstructive apnea hypopnea index (oAHI), central apnea hypopnea index (CAHI), time spent with CO2 levels &gt; 50 mmHg, time (minutes) spent with saturations &lt;88% (T88), and saturation nadir (minO2sat). Exclusion criteria: follow up studies, and studies post procedures. Data presented by descriptive statistics and comparison by unpaired t-test. Results A total of 526 children with DS underwent PSG during the collection time. Forty two fit criteria (Mean age 6.6 months, male 66%). Diagnostic (n=13), split to oxygen (n=29, 69%). Split studies were more severe when compared with full diagnostic AHI (Mean 44.7 vs. 14.8, p=0.0007), T88 (Mean 12.5 vs. 0.2 p=0.03) and minO2sat (77.6 vs. 85.8%, p=0.01). Overall mean oAHI was 33.7 (S.D. 30) CAI was 3.4 (S.D. 3.1). 5/31 with reliable capnography had SH (16.1%) with no difference in age vs. the non-SH group (6.0 [3.2] vs. 6.6 [3.1], p&gt;0.05). Overall, oAHI was more severe in infants with hypoventilation (58.9 [23.6] vs. 29.3 [63],p&gt;0.05). Ten infants spent &gt;5 min with saturations &lt;88% (21.4%). All infants with hypoxemia had OSA (oAHI Mean 66.5 SD 40). Infants with OSA and hypoxemia had worse oAHI than those without hypoxemia (p&lt;0.05). Conclusion Our data shows that a large percent of infants with DS (69%) required a split study due to severe OSA (mean oAHI 66.5) or hypoxemia (21.4%). The overall mean AHI for this age group was 33.7. Hypoventilation was present in 16.1%. This study highlights the high prevalence of SDB in infants with DS and supports early PSG assessment in this patient population. Support (If Any)

Introduction Hypotonia is common in infants with Trisomy 21. This can cause masticatory and oropharyngeal muscle weakness increasing the risk for dysphagia and sleep disordered breathing. Data describing the occurrence of dysphagia and sleep disordered breathing in infants with Trisomy 21 is limited. This study aims to determine the frequency and severity of dysphagia and its relationship to polysomnogram parameters in infants with Trisomy 21. Methods Retrospective chart review of patients with Trisomy 21 &lt;12 months old that underwent polysomnography at Seattle Children’s Hospital between October 1, 2015-August 23, 2021. Data collected included: sex, age, presence of dysphagia, recommended thickener type and polysomnographic data. Results A total of 526 polysomnograms in patients with Trisomy 21 were performed. Forty-one studies were identified in &lt;12 months old. Results in mean ± SD showed: age 6.5 months + 3, 66% were male and 73% were diagnosed with dysphagia through a video fluoroscopic swallow study. In those with dysphagia, 16% can tolerate thin liquids, 20% prescribed nectar-thick, 7% prescribed honey-thick and 57% were G-tube dependent. In patients with dysphagia compared to those without dysphagia: there was higher total AHI of 43.3 +/- 35.3 vs. 22.6 +/- 10.6 (p=0.006), oAHI of 39.7 +/- 35.5 vs. 17.2 +/- 11.6 (p=0.004), CAI of 3.4 +/- 3.4 vs. 3.4 +/- 1.8 (p=0.11), oxygen saturation nadir of 78.6 +/- 10.6 vs. 83.1 +/- 6.6 (p=0.11) and percentage total sleep time TcCO2 &gt;50 mmHg of 44.6 +/- 42.6 vs. 31 +/- 40.3 (p=0.44). Worse dysphagia was positively correlated with a higher oAHI (r=0.38, p=0.03). Conclusion There is a high incidence of dysphagia and sleep disordered breathing in infants with Trisomy 21. Dysphagia severity correlated with oAHI severity. Dysphagia in OSA can be due to the sensory and motor changes of the pharynx with impaired swallow-breathing mechanism. Chronic microaspiration can also result in decreased pulmonary reserve from lower airway inflammation or lung parenchymal disease, which may lead to worse sleep disordered breathing. Current guidelines suggest screening at school age or when there are clinical symptoms of OSA in Trisomy 21. However, results suggest the need to evaluate and intervene earlier especially in infants with dysphagia. Support (If Any)