Portable Respiratory Monitor Research Articles

Validation of a Portable Respiratory Monitoring System for the Diagnosis of Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease: A Crossectional Study.

Introduction Portable respiratory monitoring (PM) has been used to diagnose obstructive sleep apnea (OSA) in the general population. However, its validation in patients with both OSA and chronic obstructive pulmonary disease (COPD), remains unclear. Objective The aim of the study was to validate PM for the diagnosis of OSA in patients with COPD. Materials and Methods In this crossectional study, COPD patients were submitted simultaneously to polysomnography (PSG) and PM. Moreover, the risk for OSA was verified by the Berlin, NoSAS, and STOP-BANG questionnaires. Sensitivity, specificity, positive predictive value, and negative predictive value for PM were calculated for the cutoff points of the hypopnea apnea index (AHI) of 5, 15, and 30 events/hour, as well as for the questionnaires. The Bland-Altman test and correlation analyses between the AHI of the PSG and PM were performed. Results A total of 103 patients were evaluated (age 67.5 ± 9.9 years, 60% men). The STOP-BANG questionnaire had the highest sensitivity for OSA diagnosis, at 94.4% (72.7-99.9%). The sensitivity of PM decreased (87.0, 66.7, and 44.4%), and the specificity increased 40.0, 78.6, and 100.0%) as the AHI cutoff point increased from 5, 15, and 30. The Bland-Altman test indicated good limits of agreement (AHI = 5.5 ± 11.7 events/hour). Therefore, the AHI results of the PM showed a strong and positive correlation with those of the PSG (r = 0.70, p < 0.0001). Conclusion The PM test can be a useful tool for OSA diagnosis in patients with COPD.

Abstract TMP108: Improvements In Sleep Apnea Are Associated With Improvements In NIHSS In The First Year After Stroke.

Introduction: Sleep apnea, a very common condition among post-stroke patients, is associated with worse functional, cognitive, and neurological outcomes after stroke. Little is known about the association between change of sleep apnea and changes in outcome over time. Methods: Associated with the Brain Attack Surveillance in Corpus Christi (BASIC) project, ischemic stroke patients (2016-2019) were offered sleep apnea testing with a portable respiratory monitor (ApneaLink Plus) shortly after stroke and at 3, 6, and 12 months post-stroke. Sleep apnea was quantified using the respiratory event index (REI), the number of apneas plus hypopneas per recording hour. At 3, 6, and 12-months post-stroke, functional outcome was assessed using activities of daily living (ADL)/instrumental activities of daily living (IADL) score (1-4, lower better); cognitive outcome was assessed using the Modified Mini-Mental State Examination (3MS) (0-100, higher better); neurological outcome was assessed using the NIHSS (0-42, lower better). Multivariate mixed models were fitted under a Bayesian approach to obtain random slopes in REI over time and the three outcomes (1-unit change in outcome per month), adjusted for age, sex, ethnicity, pre-stroke function and cognitive status, education, marital status, stroke history, tpa use, recurrent stroke, and depression. Linear regression models assessed the association between random slope of REI and random slopes of the three outcomes. Results: Of the 482 Mexican American or non-Hispanic white participants with at least one REI measurement, in fully adjusted models, improvement in sleep apnea was significantly associated with improvement in NIHSS (0.0094 (95% CI: 0.0070, 0.0118)) but not with changes in ADL/IADL or 3MS. Conclusions: Improvement in sleep apnea paralleled improvement in neurological status over the first year after stroke.

“Are you breathing?” – Design, build and testing of a low-cost, portable respiratory rate monitor

Abstract A patient’s respiratory rate is one of the critical vital signs that is a determinant of patient well-being. However, it is all too often neglected or misreported by health care professionals. This study presents the design, build and testing of a low-cost, portable monitor to facilitate accurate reporting of respiratory rate. The monitor comprised a thermistor-based transducer to capture the breath cycle of patients based on the temperature differential created across the thermistor. The signal was conditioned and processed such that the signal could be analysed to identify the peaks and ultimately determine the respiratory rate. For a total cost at the time of development of less than C40, the integrated system demonstrated a modest average error of 5.6% across a range of different ambient temperatures, rate and depth of breathing, and orifice of breathing. This is comparable with other commercial and custom devices. The presented monitor may be of interest for use in an emergency room or clinical setting, especially in severely resource-constrained countries.

P10‐22: The diagnostic role of portable respiratory monitor in heart failure patient with Cheyne Stoke respiration

P10‐22: The diagnostic role of portable respiratory monitor in heart failure patient with Cheyne Stoke respiration

Physiological respiratory parameters in pre-hospital patients with suspected COVID-19: A prospective cohort study.

The COVID-19 pandemic has presented emergency medical services (EMS) worldwide with the difficult task of identifying patients with COVID-19 and predicting the severity of their illness. The aim of this study was to investigate whether physiological respiratory parameters in pre-hospital patients with COVID-19 differed from those without COVID-19 and if they could be used to aid EMS personnel in the prediction of illness severity. Patients with suspected COVID-19 were included by EMS personnel in Uppsala, Sweden. A portable respiratory monitor based on pneumotachography was used to sample the included patient's physiological respiratory parameters. A questionnaire with information about present symptoms and background data was completed. COVID-19 diagnoses and hospital admissions were gathered from the electronic medical record system. The physiological respiratory parameters of patients with and without COVID-19 were then analyzed using descriptive statistical analysis and logistic regression. Between May 2020 and January 2021, 95 patients were included, and their physiological respiratory parameters analyzed. Of these patients, 53 had COVID-19. Using adjusted logistic regression, the odds of having COVID-19 increased with respiratory rate (95% CI 1.000-1.118), tidal volume (95% CI 0.996-0.999) and negative inspiratory pressure (95% CI 1.017-1.152). Patients admitted to hospital had higher respiratory rates (p<0.001) and lower tidal volume (p = 0.010) compared to the patients who were not admitted. Using adjusted logistic regression, the odds of hospital admission increased with respiratory rate (95% CI 1.081-1.324), rapid shallow breathing index (95% CI 1.006-1.040) and dead space percentage of tidal volume (95% CI 1.027-1.159). Patients taking smaller, faster breaths with less pressure had higher odds of having COVID-19 in this study. Smaller, faster breaths and higher dead space percentage also increased the odds of hospital admission. Physiological respiratory parameters could be a useful tool in detecting COVID-19 and predicting hospital admissions, although more research is needed.

Compressible and Stretchable Magnetoelectric Sensors Based on Liquid Metals for Highly Sensitive, Self-Powered Respiratory Monitoring.

Healthcare monitoring, especially for respiration, has attracted tremendous attention from academics considering the great significance of health information feedback. The respiratory rate, as a critical health indicator, has been used to screen and evaluate potential illness risks in early medical diagnoses. A self-powered sensing system for medical monitoring is critical and imperative due to needless battery replacement and simple assembly. However, the development of a self-powered respiratory sensor with highly sensitive performance is still a daunting challenge. In this work, a compressible and stretchable magnetoelectric sensor (CSMS) with an arch-shaped air gap is reported, enabling self-powered respiratory monitoring driven by exhaled/inhaled breath. The CSMS contains two key functional materials: liquid metals and magnetic powders both with low Young's modulus, allowing for sensing compressibility and stretchability simultaneously. More importantly, such a magnetoelectric sensor exhibits mechanoelectrical converting capacity under an external force, which has been verified by Maxwell numerical simulation. Owing to the air-layer introduction, the magnetoelectric sensors achieve high sensitivity (up to 17.73 kPa-1), fast response, and long-term stability. The highly sensitive and self-powered magnetoelectric sensor can be further applied as a noninvasive, miniaturized, and portable respiratory monitoring system with the aim of warning for potential health risks. We anticipate that this technique will create an avenue for self-powered respiratory monitoring fields.

Long-Term Auscultation in Chronic Obstructive Pulmonary Disease: Renaissance of an Ideograph of Medical Care

Background: Electronic auscultation technology has advanced dramatically in the last few years. Therefore, long-term pulmonary auscultation could provide additional information about respiratory system by monitoring acute chronic obstructive pulmonary disease (AECOPD) exacerbations or by identifying wheezing phenotypes amongst stable COPD patients. Objectives: Comparison of respiratory sounds in stable versus AECOPD patients recorded with a portable respiratory sound monitor over a period of 24 h. Methods: This prospective trial evaluated cough and wheezing events using an auscultation monitor specially developed for this purpose with 4 integrated highly sensitive microphones, in stable and severely AECOPD patients for a period of 24 h in an inpatient setting. Results: Twenty stable COPD patients (12 male, 60%) and 20 severely exacerbated COPD patients (14 male, 70%) were analyzed. In AECOPD patients, long-term auscultation revealed a significantly higher number of wheezing epochs than stable COPD patients (591 [IQR: 145–1,645] vs. 152 [IQR: 90–400]; p = 0.021). Conversely, cough epochs did not differ between AECOPD and stable COPD patients (213 [IQR: 140–327] vs. 162 [IQR: 123–243]; p = 0.256). The Borg-dyspnea scale, CAT score, and total CCQ score each showed no correlation with wheezing frequency, while CAT and CCQ scores did correlate with coughing frequency. Conclusion: Wheezing, but not coughing, occurs more frequently in AECOPD patients than in stable COPD patients, indicating that severe wheezing is an important clinical sign of exacerbation, while coughing is not. Therefore, the patterns of wheezing and coughing, as assessed by long-term auscultation, differ in stable versus exacerbated COPD patients.

A Novel, Contactless, Portable “Spot-Check” Device Accurately Measures Respiratory Rate

Abstract Respiratory rate (RR) is an important vital sign used in the initial and ongoing assessment of acutely ill patients. It is also used as a predictor of serious deterioration in a patient's clinical condition. Convenient electronic devices exist for measurement of pulse, blood pressure, oxygen saturation, and temperature. Although devices which measure RR exist, none has entered everyday clinical practice. We have developed a contactless portable respiratory rate monitor (CPRM) and evaluated the agreement in respiratory rate measurements between existing methods and our new device. The CPRM uses thermal anemometry to measure breath signals during inspiration and expiration. RR data were collected from 52 healthy adult volunteers using respiratory inductance plethysmography (RIP) bands (established contact method), visual counting of chest movements (established noncontact method), and the CPRM (new method), simultaneously. Two differently shaped funnel attachments to the CPRM were evaluated for each volunteer. Data showed a good agreement between measurements from the CPRM and the gold standard RIP, with intraclass correlation coefficient (ICC): 0.836, mean difference 0.46 and 95% limits of agreement of −5.90 to 6.83. When separate air inlet funnels of the CPRM were analyzed, stronger agreement was seen with an elliptical air inlet; ICC 0.908, mean difference 0.37 with 95% limits of agreement −4.35 to 5.08. A contactless device for accurately and quickly measuring respiratory rate will be an important triage tool in the clinical assessment of patients. More testing is needed to explore the reasons for outlying measurements and to evaluate in the clinical setting.

Abstract WP251: Sleep Apnea and Early Neurological Deterioration in Acute Ischemic Stroke

Background and Purpose: Evidence of an association between sleep apnea (SA) and early neurological deterioration (END) in acute phase ischemic stroke is scant. We investigated the prevalence of SA and the impact of SA severity on END in acute ischemic stroke (AIS) patients. Methods: We prospectively enrolled consecutive AIS patients admitted to our stroke unit within 72 hours of symptom onset. SA severity was assessed with ApneaLink - a validated portable respiratory monitor. SA was defined as an apnea-hypopnea index (AHI) of ≥ 5/hour. END was defined as an incremental increase in the National Institutes of Health Stroke Scale (NIHSS) score by ≥ 1 point in motor power, or ≥ 2 points in the total score within the first week after admission. Results: Of the 305 patients studied, 254 (83.3%) patients had SA (AHI ≥ 5/hour), and of these, 114 (37.4%) had mild SA (AHI 5-14/hour), 59 (19.3%) had moderate SA (AHI 15-29/hour), and 81 (26.6%) had severe SA (AHI ≥ 30/hour). Thirty-six (11.8%) patients experienced END: 2 of the 51 (3.9%) patients without SA and 34 of the 254 (14.4%) patients with SA. Multivariable regression analysis showed AHI independently predicted END (odds ratio 1.024; 95% confidence interval 1.006 to 1.042; p = 0.008). Conclusions: SA is common in the acute phase of ischemic stroke, and SA severity is associated with the risk of END.

Sleep Apnea and Early Neurological Deterioration in Acute Ischemic Stroke

Background and purposeEvidence of an association between sleep apnea (SA) and early neurological deterioration (END) in acute phase ischemic stroke is scant. We investigated the prevalence of SA and the impact of SA severity on END in acute ischemic stroke (AIS) patients. MethodsWe prospectively enrolled consecutive AIS patients admitted to our stroke unit within 72 hours of symptom onset. SA severity was assessed with ApneaLink—a validated portable respiratory monitor. SA was defined as an apnea-hypopnea index (AHI) of greater than or equal to 5 per hour. END was defined as an incremental increase in the National Institutes of Health Stroke Scale (NIHSS) score by greater than or equal to 1 point in motor power, or greater than or equal to 2 points in the total score within the first week after admission. ResultsOf the 305 patients studied, 254 (83.3%) patients had SA (AHI ≥ 5 per hour), and of these, 114 (37.4%) had mild SA (AHI 5-14 per hour), 59 (19.3%) had moderate SA (AHI 15-29 per hour), and 81 (26.6%) had severe SA (AHI ≥ 30 per hour). Thirty-six (11.8%) patients experienced END: 2 of the 51 (3.9%) patients without SA and 34 of the 254 (14.4%) patients with SA. Multivariable regression analysis showed AHI independently predicted END (odds ratio 1.024; 95% confidence interval 1.006 to 1.042; P = .008). ConclusionsSA is common in the acute phase of ischemic stroke, and SA severity is associated with the risk of END.

The Clinical Value of N-Terminal Pro B-Type Natriuretic Peptide in Evaluating Obstructive Sleep Apnea in Patients With Coronary Artery Disease.

Natriuretic peptides have been identified as biomarkers of increased myocardial wall stress in the context of obstructive sleep apnea (OSA) in the general population. However, the relationship between N-terminal pro B-type natriuretic peptide (NT-proBNP) and OSA remains unclear in patients with coronary artery disease (CAD). Hence, we aimed to investigate the clinical value of NT-proBNP in evaluating OSA in a large population of patients with CAD. Consecutive patients with CAD were prospectively enrolled between February 2015 and March 2018. Portable respiratory monitoring was applied to facilitate the diagnosis of sleep apnea. Patients were as assigned to the non-OSA (when the respiratory events index [REI] or 3% oxygen desaturation index [ODI] < 15 events/h) and OSA (when the REI or 3% ODI ≥ 15 events/h) groups. Multivariate analyses were used to explore the independent association between NT-proBNP levels and OSA. A total of 1,292 consecutive patients were included with a mean NT-proBNP value of 826.57 μg/L. Patients with high levels of NT-proBNP experienced increasing severity of OSA in those with CAD (P = .0004). Univariate analysis demonstrated that NT-proBNP was a risk factor for OSA (odds ratio [OR] 1.10, 95% confidence interval [CI] 1.03-1.18, P = .005). In addition, multivariate analysis revealed that NT-proBNP was independently associated with the presence of OSA (OR 1.11, 95% CI 1.02-1.20, P = .012) even after adjusting for other cofounding factors. Elevated levels of NT-proBNP were independently associated with a higher likelihood of OSA in patients with CAD. Periodically screening for NT-proBNP levels may provide early identification of OSA.

Portable respiratory polygraphy monitoring of obese mothers the first night after caesarean section with bupivacaine/morphine/fentanyl spinal anaesthesia.

Background: Obesity, abdominal surgery, and intrathecal opioids are all factors associated with a risk for respiratory compromise. The aim of this explorative trial was to study the apnoea/hypopnea index 1st postoperative night in obese mothers having had caesarean section (CS) in spinal anaesthesia with a combination of bupivacaine/morphine and fentanyl. Methods: Consecutive obese (BMI >30 kg/m 2) mothers, ≥18 years, scheduled for CS with bupivacaine/morphine/fentanyl spinal anaesthesia were monitored with a portable polygraphy device Embletta /NOX on 1 st postoperative night. The apnoea/hypopnea index (AHI) was identified by clinical algorithm and assessed in accordance to general guidelines; number of apnoea/hypopnea episodes per hour: <5 "normal", ≥5 and <15 mild sleep apnoea, ≥15 and <30 moderate sleep apnoea, ≥ 30 severe sleep apnoea. Oxygen desaturation events were in similar manner calculated per hour as oxygen desaturation index (ODI). Results: Forty mothers were invited to participate: 27 consented, 23 were included, but polysomnography registration failed in 3. Among the 20 mothers studied: 11 had an AHI <5 ( normal), 7 mothers had AHI ≥5 but <15 ( mild OSAS) and 2 mothers had AHI ≥15 ( moderate OSA), none had an AHI ≥ 30. The ODI was on average 4.4, and eight patients had an ODI >5. Mothers with a high AHI (15.3 and 18.2) did not show high ODI. Mean saturation was 94% (91-96%), and four mothers had mean SpO 2 90-94%, none had a mean SpO2<90%. Conclusion: Respiratory polygraphy 1 st night after caesarean section in spinal anaesthesia with morphine in moderately obese mothers showed AHIs that in sleep medicine terms are considered normal, mild and moderate. Obstructive events and episodes of desaturation were commonly not synchronised. Further studies looking at preoperative screening for sleep apnoea in obese mothers are warranted but early postop respiratory polygraphy recording is cumbersome and provided sparse important information.

Portable respiratory polygraphy monitoring of obese mothers the first night after caesarean section with bupivacaine/morphine/fentanyl spinal anaesthesia

Background: Obesity, abdominal surgery, and intrathecal opioids are all factors associated with a risk for respiratory compromise. The aim of this explorative trial was to study the apnoea/hypopnea index 1st postoperative night in obese mothers having had caesarean section (CS) in spinal anaesthesia with a combination of bupivacaine/morphine and fentanyl. Methods: Consecutive obese (BMI >30 kg/m 2) mothers, ≥18 years, scheduled for CS with bupivacaine/morphine/fentanyl spinal anaesthesia were monitored with a portable polygraphy device Embletta /NOX on 1 st postoperative night. The apnoea/hypopnea index (AHI) was identified by clinical algorithm and assessed in accordance to general guidelines; number of apnoea/hypopnea episodes per hour: <5 “normal”, ≥5 and <15 mild sleep apnoea, ≥15 and <30 moderate sleep apnoea, ≥ 30 severe sleep apnoea. Oxygen desaturation events were in similar manner calculated per hour as oxygen desaturation index (ODI). Results: Forty mothers were invited to participate: 27 consented, 23 were included, but polysomnography registration failed in 3. Among the 20 mothers studied: 11 had an AHI <5 ( normal), 7 mothers had AHI ≥5 but <15 ( mild OSAS) and 2 mothers had AHI ≥15 ( moderate OSA), none had an AHI ≥ 30. The ODI was on average 4.4, and eight patients had an ODI >5. Mothers with a high AHI (15.3 and 18.2) did not show high ODI. Mean saturation was 94% (91-96%), and four mothers had mean SpO 2 90-94%, none had a mean SpO2 <90%. Conclusion: Respiratory polygraphy 1 st night after caesarean section in spinal anaesthesia with morphine in moderately obese mothers showed AHIs that in sleep medicine terms are considered normal, mild and moderate. Obstructive events and episodes of desaturation were commonly not synchronised. Further studies looking at preoperative screening for sleep apnoea in obese mothers are warranted but early postop respiratory polygraphy recording is cumbersome and provided sparse important information.

Portable respiratory polygraphy monitoring of obese mothers the first night after caesarean section with bupivacaine/morphine/fentanyl spinal anaesthesia

Background: Obesity, abdominal surgery, and intrathecal opioids are all factors associated with a risk for respiratory compromise. The aim of this observational study was to explore the use of portable respiratory polygraphy for monitoring of obese mothers for respiratory depression the first night after caesarean section (CS) with bupivacaine/morphine/fentanyl spinal anaesthesia. Methods: Consecutive obese (BMI >30 kg/m 2) mothers, ≥18 years, scheduled for CS with bupivacaine/morphine/fentanyl spinal anaesthesia were monitored with a portable polygraphy device Embletta /NOX on the first postoperative night. The apnoea-hypopnea index (AHI) was identified by clinical algorithm and assessed in accordance to general guidelines. Results: Forty mothers were invited to participate: 27 consented, 23 were included, but polysomnography registration failed in 3. Among the 20 mothers: 11 had an AHI <5; 7, AHI 5-15; and 2, AHI >15. The oxygen desaturation index (ODI) was on average 4.4, and eight patients had an ODI >5. Those mothers with a high AHI (15.3 and 18.2) did not show high ODI or signs of hypercapnia on transcutaneous CO 2 registration. Mean saturation was 94% (91-96), and four mothers had mean saturation between 90-94%, but none had a mean SpO 2 <90%. Mean nadir saturation was 71% (range, 49-81%). None of the mothers showed clinical signs or symptoms of severe respiratory depression, shown by routine clinical monitoring. Conclusion: We found portable polygraphy registration during early post-CS in moderately obese mothers having had intrathecal morphine/fentanyl cumbersome and although episodes of oxygen saturation decrease were noticed, obstructive events and episodes of desaturation were commonly not synchronised. Upper airway obstructions seem not be of major importance in this clinical setting. Monitoring of respiratory rate, SpO 2 and possibly transcutaneous CO 2 in mothers at high risk of respiratory distress warrants further studies. Preoperative screening in obese patients, at risk for sleep breathing disorder, is of course of value.

A randomized controlled trial to validate the Alice PDX ambulatory device.

BackgroundObstructive sleep apnea (OSA) is a highly prevalent condition; however, the majority of patients remain undiagnosed. There is a potential to expand the diagnostic capacity of sleep laboratories. The study objective was to validate a portable respiratory monitoring device (Alice PDX) against polysomnography (PSG) in the laboratory and to assess its reliability at home.MethodsA total of 85 patients with suspected OSA (80% male, mean age 49.1±13.5 years, body mass index 29.7±6.9 kg/m2, Epworth Sleepiness Scale 10.0±5.1) were randomized to 3 diagnostic nights: 1 night simultaneous in-laboratory PSG and PDX recording; 1 night self-applied PDX at home, and 1 night in-laboratory PSG. Study data were manually scored according to American Academy of Sleep Medicine criteria.ResultsThe Alice PDX was in diagnostic agreement with simultaneously recorded reference PSG in 96.4% of studies. In 2.4% of studies the in-laboratory PDX underestimated and in 1.2% of studies it overestimated the apnea hypopnea index (AHI). The difference between the AHI from the reference PSG and the home study was similar to the difference between the PSGs (2.79 vs 0.79, p=0.08).ConclusionIn a population with a high suspicion of OSA, the Alice PDX showed a high level of diagnostic agreement with a simultaneous PSG and performed valid home diagnostic studies for OSA. If manually scored, the portable device can be used by sleep specialists for diagnosing moderate-to-severe obstructive sleep apnea in cases with a high pretest probability for the disease over a wide range of disease severity. The technology can be deployed reliably outside of the sleep laboratory setting.

Examination of a micro-electro-mechanical system based on a portable respiratory monitoring system

This study aimed to examine the feasibility of a portable respiratory monitoring system (PRMS) based on a micro-electro-mechanical system (MEMS). The performance of the PRMS was estimated by comparing the actual and the measured movements of the linear and the angular motions by using a one-dimensional motion phantom. The results indicated that differences between the actual and the measured movements ranged from −0.3% to −0.9% and from −7.07% to 2.93% for the periods and the amplitudes in linear motion and from −6.5% to 4.3% and from −9.5% to −5.2% for the periods and the amplitudes in angular motion. The PRMS reproduces a signal that is similar to the actual motion, and the uncertainty generated in the electronic error and the tilting movement was reduced when the velocities of movement were higher than 0.6 cm/s and 0.08 °/s. In this study, we found that the PRMS is applicable to respiratory motion training for relatively normal or fast respiratory cases and that with a more sensitive sensor, it can be the expanded to slower respiration cases.

Abstract 52: Brainstem Infarction is Associated with Sleep Apnea: The BASIC Sleep Project

Background: Despite hypotheses that brainstem infarction is associated with sleep apnea (SA), no specific site of infarction has been associated with post-stroke SA in existing studies, which have been relatively small. Within a larger, population-based study, we assessed the association between infarction location and SA presence and severity. Methods: Ischemic stroke patients in the Brain Attack Surveillance in Corpus Christi (BASIC) project had SA screening performed (median 13 days after stroke) with a validated portable respiratory monitor (ApneaLink Plus) (n=355). The apnea-hypopnea index (AHI) was used to measure SA severity; SA was defined conservatively as an AHI ≥10. Acute infarction location was determined based on review of CT and MRI reports by board-certified neurologists and dichotomized into brainstem involvement or none. Logistic and linear regression models were used to test the associations between brainstem involvement and SA or AHI in unadjusted and adjusted models. Results: Median age was 65 (IQR: 57, 77); 55% were male. Thirty-eight (11%) had acute infarction involving the brainstem. Of those without brainstem infarction, 59% had SA; the median AHI was 13 (interquartile range (IQR) 6, 26). Of those with brainstem infarction, 84% had SA; median AHI was 20 (IQR 11, 38). In unadjusted analysis, brainstem involvement was associated with over three times the odds of SA (OR 3.71 (95% CI: 1.52, 9.13). In a multivariable model, adjusted for demographics, BMI, stroke risk factors, and stroke severity, results were similar (OR 3.76 (95% CI: 1.44, 9.81)). Similarly, brainstem infarction was associated with AHI in unadjusted (p=0.004) and adjusted models (p=0.004). Conclusion: Acute infarction involving the brainstem was associated with both presence and severity of sleep apnea in this population-based stroke surveillance study.

Procedural sedation with dexmedetomidine during ablation of atrial fibrillation: a randomized controlled trial

Procedural sedation by non-anaesthesiologists with GABAergic anaesthetics has the potential risk of fatal respiratory depression. Dexmedetomidine works its sedative action via α2-adrenergic receptors, and is less associated with respiratory depression. We tested the usability of dexmedetomidine as a procedural sedative during ablation of atrial fibrillation (AF). Consecutive patients were randomized to be treated with dexmedetomidine (n = 43) or thiamylal (n = 44) as sedatives during AF ablation. Apnoeic and body movement events were monitored using a novel portable respiratory monitor, the SD-101, during the procedure. Although the majority of the patients receiving dexmedetomidine required rescue sedations with thiamylal, the respiratory disturbance index (RDI) defined as the total number of sleep-disordered breathing events divided by the recording time (10.4 ± 5.1 vs. 18.2 ± 8.1 events/h; P < 0.0001) and movement index defined as the number of body movement events per hour (7.6 ± 6.1 vs. 11.0 ± 5.5 events/h; P = 0.0098) were both significantly lower in the dexmedetomidine arm than in the thiamylal arm. A multivariate linear regression analysis including potential factors revealed that dexmedetomidine vs. thiamylal was solely and independently associated with the RDI (β = -0.62; P = 0.0031). The occurrence of hypotension [9 (21%) vs. 4 (9%); P = 0.14] and bradycardia [4 (9%) vs. 4 (9%); P = 1.0] were similar in the patients with dexmedetomidine and thiamylal. Procedural sedation with dexmedetomidine may assure safety and patient immobility during AF ablation, and therefore may be a potential alternative for that with GABAergic anaesthetics.

Don't move during ablation of atrial fibrillation!

BackgroundRestless patient is recalcitrant during ablation of atrial fibrillation (AF). We aimed to assess the association between patient movements during AF ablation and its outcome. MethodsWe examined the body movement during AF ablation in 78 patients with the use of a novel portable respiratory monitor, the SD-101, which also has the ability to quantify the frequency of body movements. ResultsThe body movement index, defined as the number of the units of time with body movement events divided by the recording time (11.4±6.5events/h), was significantly correlated with the ablation time defined as the time from the first point of the ablation to the end of the procedure (1.2±0.3h) (r=0.35; p=0.0014) and a total radiofrequency energy applied (56.6±17.7kW) (r=0.36; p=0.0015). A multiple linear regression analysis showed that non-paroxysmal AF (β=0.25; p=0.036) and the body movement index (β=0.36; p=0.0019) were independent determinants of the ablation time. The body movement index was similar in patients with and without recurrence of AF. ConclusionsKeeping patients motionless may be important to reduce the procedural duration of AF ablation.

Clinical significance of sleep-disordered breathing induced by sedatives during ablation of atrial fibrillation

Sleep-disordered breathing (SDB) frequently is induced by sedation during ablation of atrial fibrillation (AF). We tested whether or not sedative-induced SDB is associated with clinical sleep apnea syndrome (SAS). We examined SDB observed during intra-ablation sedation with a novel portable respiratory monitor (PM), SD-101, in 140 patients undergoing AF ablation without any known SAS. A sleep study was repeated the next night of the ablation with the simultaneous use of the SD-101 and type 3 PM, APNOMONITOR V. The respiratory disturbance index (RDI) during sedation (20.0±7.8 events/h) was significantly correlated with the RDI measured by the SD-101 during the night (15.8±13.7 events/h; r=0.50) and the RDI assessed by the APNOMONITOR V during the night (12.7±12.3 events/h; r=0.55). An excellent agreement was found between the RDIs simultaneously measured with the 2 PMs (intraclass correlation coefficient, 0.84), especially for an RDI of ≥30 events/h (κ statistic value, 0.82). The area under the receiver-operating characteristic curve for the RDI with the use of the SD-101 during sedation to identify the patients with an RDI of ≥30 events/h by both PMs during the night was 0.92. A left atrial diameter of >40 mm (odds ratio [OR], 4.10) and an RDI during sedation of >20 events/h (OR, 17.75) were independently associated with having an RDI of ≥30 events/h with both PMs during the night. Frequent episodes of sedative-induced SDB may have a diagnostic value for SAS in patients with AF.