published_or_final_version / Medicine / Master / Master of Philosophy

Tracheal respiratory sounds analysis has been investigated as a non-invasive method to estimate respiratory flow and upper airway obstruction. However, the flow-sound relationship is highly variable among subjects which makes it challenging to estimate flow in general applications. Therefore, a robust model for acoustical flow estimation in a large group of individuals did not exist before. On the other hand, a major application of acoustical flow estimation is to detect flow limitations in patients with obstructive sleep apnea (OSA) during sleep. However, previously the flow--sound relationship was only investigated during wakefulness among healthy individuals. Therefore, it was necessary to examine the flow-sound relationship during sleep in OSA patients. This thesis takes the above challenges and offers innovative solutions. First, a modified linear flow-sound model was proposed to estimate respiratory flow from tracheal sounds. To remove the individual based calibration process, the statistical correlation between the model parameters and anthropometric features of 93 healthy volunteers was investigated. The results show that gender, height and smoking are the most significant factors that affect the model parameters. Hence, a general acoustical flow estimation model was proposed for people with similar height and gender. Second, flow-sound relationship during sleep and wakefulness was studied among 13 OSA patients. The results show that during sleep and wakefulness, flow-sound relationship follows a power law, but with different parameters. Therefore, for acoustical flow estimation during sleep, the model parameters should be extracted from sleep data to have small errors. The results confirm reliability of the acoustical flow estimation for investigating flow variations during both sleep and wakefulness. Finally, a new method for sleep apnea detection and monitoring was developed, which only requires recording the tracheal sounds and the blood's oxygen saturation level (SaO2) data. It automatically classifies the sound segments into breath, snore and noise. A weighted average of features extracted from sound segments and SaO2 signal was used to detect apnea and hypopnea events. The performance of the proposed approach was evaluated on the data of 66 patients. The results show high correlation (0.96,p < 0.0001) between the outcomes of our system and those of the polysomnography. Also, sensitivity and specificity of the proposed method in differentiating simple snorers from OSA patients were found to be more than 91%. These results are superior or comparable with the existing commercialized sleep apnea portable monitors.

Tracheal respiratory sounds analysis has been investigated as a non-invasive method to estimate respiratory flow and upper airway obstruction. However, the flow-sound relationship is highly variable among subjects which makes it challenging to estimate flow in general applications. Therefore, a robust model for acoustical flow estimation in a large group of individuals did not exist before. On the other hand, a major application of acoustical flow estimation is to detect flow limitations in patients with obstructive sleep apnea (OSA) during sleep. However, previously the flow--sound relationship was only investigated during wakefulness among healthy individuals. Therefore, it was necessary to examine the flow-sound relationship during sleep in OSA patients. This thesis takes the above challenges and offers innovative solutions. First, a modified linear flow-sound model was proposed to estimate respiratory flow from tracheal sounds. To remove the individual based calibration process, the statistical correlation between the model parameters and anthropometric features of 93 healthy volunteers was investigated. The results show that gender, height and smoking are the most significant factors that affect the model parameters. Hence, a general acoustical flow estimation model was proposed for people with similar height and gender. Second, flow-sound relationship during sleep and wakefulness was studied among 13 OSA patients. The results show that during sleep and wakefulness, flow-sound relationship follows a power law, but with different parameters. Therefore, for acoustical flow estimation during sleep, the model parameters should be extracted from sleep data to have small errors. The results confirm reliability of the acoustical flow estimation for investigating flow variations during both sleep and wakefulness. Finally, a new method for sleep apnea detection and monitoring was developed, which only requires recording the tracheal sounds and the blood's oxygen saturation level (SaO2) data. It automatically classifies the sound segments into breath, snore and noise. A weighted average of features extracted from sound segments and SaO2 signal was used to detect apnea and hypopnea events. The performance of the proposed approach was evaluated on the data of 66 patients. The results show high correlation (0.96,p < 0.0001) between the outcomes of our system and those of the polysomnography. Also, sensitivity and specificity of the proposed method in differentiating simple snorers from OSA patients were found to be more than 91%. These results are superior or comparable with the existing commercialized sleep apnea portable monitors.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

The presence of cognitive deficits in obstructive sleep apnea (OSA) is well-documented. Specifically, short- and long-term memory, attention/vigilance, and executive function (e.g. processing speed, mental flexibility, and problem solving) are affected. Cognitive deficits in aging occur in similar areas (i.e., memory and processing speed). Given that a greater percentage of older adults experience sleep-disordered breathing as compared to middle-aged adults, it is possible that OSA may account for some of the deficits typically attributed to aging. This study investigated this hypothesis by comparing middle-aged and older adults with and without OSA on computer-based measures of cognitive performance. No effect of OSA or an interaction between OSA and age on cognitive function was found; an effect of age on processing speed, distinguishing stimuli rapidly, attention, spatial ability/mental flexibility, and both working memory and short-term visual memory was found. This study also explored whether or not cognitive function may be improved in persons with OSA by re-assessing those participants one month after treatment. An effect of treatment on improvements on processing speed, distinguishing stimuli rapidly, mental flexibility, and short term memory was found. Overall, findings reflect the ability of treatment to improve cognitive function among OSA patients, regardless of lack of deficits when compared to those without OSA.

Bakgrund: Obstruktivt sömnapnésyndrom (OSAS) är en vanlig sömnrelaterad andningsstörning som innebär att patienten får apnéer (totalt andningsflödesstopp) och/eller hypoapnéer (delvis andningsflödesstopp) under nattsömnen. Dessa leder till störd nattsömn, vilket leder till kroppslig påverkan. OSAS ger både fysisk och psykisk påverkan, vilket i sin tur resulterar i att många patienter upplever sämre livskvalité. En av de vanligaste behandlingarna för OSAS är CPAP (Continuous Positive Airway Pressure) som med hjälp av övertrycksandning hjälper till att hålla de övre luftvägarna öppna under sömn.   Syfte: Syftet med litteraturöversikten var att undersöka hur patienters livskvalité påverkas av behandling med CPAP samt om det finns vetenskapligt bevisade omvårdnadsåtgärder som underlättar för patienter att uppnå god livskvalité vid CPAP-behandling. Metod: En systematisk litteraturöversikt baserad på 10 kvantitativa originalartiklar. Resultat: Majoriteten av de genomgångna studierna visade att användning av CPAP minskar psykiska och fysiska symptom och därmed förbättrar patienternas livskvalité. Genom att följa upp patienter i sjukvården, erbjuda dem utbildningar samt gruppdiskussioner främjar man deras hälsa och höjer livskvalitén. Studierna visade också att grunden för en god omvårdnad är att sjuksköterskan har evidensbaserade kunskaper för att kunna planera och genomföra omvårdnadsåtgärder samt följa upp hur CPAP-behandlingen påverkar patienternas livskvalité. Slutsats: Användningen av CPAP förbättrar OSAS-patienternas livskvalité, bland annat genom att minska symptom. Det är av stor vikt att sjuksköterskan har tillräckliga kunskaper för att kunna undervisa samt informera patienten om sin sjukdom och behandling. Detta hjälper patienter till en bättre egenvård, vilket har en stor betydelse för livskvalitet.

Obstructive sleep apnea is a chronic illness with increasing prevalence. In addition to associated cardiovascular comorbidities, obstructive sleep apnea syndrome has been linked to poor quality of life, occupational accidents, and motor vehicle crashes secondary to excessive daytime sleepiness. Although continuous positive airway pressure is the gold standard for sleep apnea treatment, its effects on quality of life are not well defined. In the current study we investigated the effects of treatment on quality of life using the data from the Apnea Positive Pressure Long-term Efficacy Study (APPLES), a randomized controlled trial of continuous positive airway pressure (CPAP) versus sham CPAP. The Calgary Sleep Apnea Quality of Life Index (SAQLI) was used to assess quality of life. Overall we found no significant improvement in quality of life among sleep apnea patients after CPAP treatment. However, after stratifying by OSA severity, it was found that long-term improvement in quality of life might occur with the use of CPAP in people with severe and possibly moderate sleep apnea, and no demonstrable improvement in quality of life was noted among participants with mild obstructive sleep apnea.

Sömnen är en naturlig del av människans liv och sömnstörning påverkar den vakna tidens kvalité samt det allmänna välmående. För att bibehålla en god hälsa är det av stor vikt att sova utan avbrott. Obstruktiv sömnapné (OSA) är ett tillstånd som orsakar andningsuppehåll under sömn och stör därmed sömnens effekt vilket ökar risk för andra allmänna sjukdomstillstånd. Tandvården är en organisation som träffar patienter regelbundet för undersökning av den orala hälsan. Patientens egen berättelse samt intra orala markörer kan vara tecken på symtom på OSA. Det finns brist på fördjupad kunskap kring tandvårdens erfarenhet kring patienter med OSA. Syftet med studien var att beskriva legitimerad tandvårdspersonals erfarenheter av vuxna tandvårdspatienter med obstruktiv sömnapné (OSA). Resultat Resultatet visar att erfarenheter hos tandvårdspersonalen varierar vad det gäller patienter med OSA. ”Kliniska erfarenheter av OSA” med underkategorier som patientmötet, betydelsen av hälsodeklarationen, kliniska markörer samt ”Omhändertagande” med underkategorierna prevention oral hälsa och samarbete med hälso- och sjukvården, var det som speglade tandvårdspersonalens erfarenheter. Slutsats Legitimerad tandvårdpersonal har en betydande roll för den orala och allmänna hälsan. Patienter med OSA symtom kan uppmärksammas i tandvården men mer kunskap och verktyg krävs inom området för att ett samarbete med hälso- och sjukvården kan skapas.

INTRODUÇÃO: Uma alta prevalência de apnéia obstrutiva do sono (AOS) tem sido relatada em paciente com doença arterial coronária (DAC). Vários mecanismos relacionados à AOS, incluindo dessaturação da oxi-hemoglobina e aumento da demanda de oxigênio, aumento da atividade simpática bem como estado pro trombótico, podem ser perigosos nos pacientes com DAC. Entretanto, a AOS é pouco reconhecida e não é rotineiramente pesquisada nos pacientes admitidos em unidade de cuidados coronários (UCC) com DAC. O padrão ouro para o diagnóstico de AOS é a polissonografia noturna (PSG), método impraticável na UCC, pois implica no deslocamento do paciente para o laboratório de sono. OBJETIVOS: Construir e validar um monitor de oximetria para diagnóstico de AOS em pacientes admitidos na UCC com diagnóstico de DAC aguda. MÉTODOS: Foi inicialmente desenvolvido monitor de oximetria continua que registra os dados derivados dos monitores da UCC e permite a determinação do índice de dessaturação da oxi-hemoglobina (IDO) através de análise visual da curva de oximetria. O monitor foi então utilizado em pacientes consecutivos admitidos na UCC com diagnóstico de DAC aguda. Uma amostra desta população foi também estudada através de PSG, num período máximo de três meses após a alta. RESULTADOS: Trinta e sete pacientes foram estudados através de monitorização de oximetria durante a noite na UCC. PSG foi também realizada em vinte pacientes. AOS, diagnosticada pelo monitor de oximetria contínua (IDO > 5/hora), estava presente em 43% dos pacientes. AOS foi diagnosticada em 45% dos pacientes estudados com PSG (índice de apnéia e hipopnéia > 15 eventos por hora). Houve um bom nível de concordância entre o diagnóstico de AOS pelo monitor de oximetria na UCC e pela polissonografia - kappa = 0.898; p < 0.0001. O IDO determinado pelo monitor se correlacionou de forma significativa com o índice de apnéia e hipopnéia (r = 0.737; p < 0.0001). O diagnóstico de AOS através do monitor demonstrou sensibilidade de 88,9% e especificidade de 100%. CONCLUSÃO: O monitor desenvolvido no presente trabalho, que permite o registro da oximetria contínua a partir de dados que já são habitualmente coletados na UCC, é um método simples e preciso para o diagnóstico de AOS na UCC. / BACKGROND: A high prevalence of Obstructive sleep apnea (OSA) has been reported in patients with coronary artery disease (CAD). Several OSA related mechanisms, such as oxygen desaturation, high sympathetic activity, increased cardiac oxygen demand and a prothrombotic state, may be particularly dangerous in acute CAD patients. Nevertheless, OSA is frequently underdiagnosed and patients with CAD are not routinely screened for OSA when admitted to the Coronary Care Unit (CCU). OBJECTIVES: To build and validate a continuous overnight oximetry, by recording oximetry data derived from the CCU monitor, for the detection of OSA in acute CAD patients. DESIGN: We studied consecutive patients recruited on the basis of the presence of acute CAD requiring CCU, analyzed overnight continuous oximetry data and further compared it with full overnight polysomnography (PSG). RESULTS: Thirty-seven patients underwent overnight oxygen saturation monitoring in the CCU and 20 of these patients were submitted to PSG, performed within 3 months after hospital discharge. OSA was present in 43% and 45% of the patients studied by overnight oxygen saturation monitoring and PSG, respectively. The oxymetry derived oxygen desaturation index and the PSG derived apnea hypopnea index were strongly correlated (r = 0,737; p < 0,0001). There was a good level of agreement between abnormal oxymetric results and abnormal PSG results (kappa = 0.898; p < 0,0001). Overnight oximetry had a sensitivity of 88.9% and a specificity of 100% for OSA diagnosis. CONCLUSIONS: Continuous overnight oximetry derived from monitors that are already present in the CCU is a simple and accurate method for the diagnosis of OSA in the CCU.

INTRODUÇÃO. Estudos anteriores demonstraram que pacientes com síndrome metabólica (SMet) e apnéia obstrutiva do sono (SAOS) apresentam hiperativação simpática e hipersensibilidade quimiorreflexa. Neste trabalho, testamos as hipóteses de que: 1) dieta hipocalórica associada à treinamento físico (D+TF) melhora a sensibilidade quimiorreflexa em pacientes com SMet e 2) Os efeitos da D+TF seriam mais pronunciados em pacientes com SMet+AOS que em pacientes sem AOS (SMet-AOS). MÉTODOS. Vinte e sete pacientes nunca tratados da SMet (ATP-III) foram alocados em: 1) SMet+AOS (n = 15, 53±2 anos) e 2) SMet-OSA (n = 12, 43±2 anos). A AOS foi caracterizada por um índice de apnéia-hipopnéia (IAH)> 15 eventos / hora (polissonografia). Atividade nervosa simpática muscular (ANSM) foi avaliada pela técnica de microneurografia e pressão arterial (PA) pelo método oscilatório. A sensibilidade quimiorreflexa periférica foi avaliada através da inalação de uma mistura gasosa contendo 10% O2 e 90% N2 com titulação de CO2; e a sensibilidade quimiorreflexa central através da inalação de 7% CO2 e 93% O2 por 3 min. A dieta hipocalórica foi de -500 kcal da taxa metabólica de repouso e o treinamento físico se estendeu por 4 meses, 3 vezes/ semana. RESULTADOS. A associação da D+TF reduziu semelhantemente peso corporal (5,5±0,7 e 6,2±0,6 kg, P = 0,44), circunferência abdominal (CA, 5,6±1,2 e 5,4±1,0 cm, P = 0,91), PA sistólica (10,9±3,2 vs 13,3±3,5 mmHg, P = 0,62) e diastólica (8,5±1,6 vs 8,3±1,4 mmHg, P = 0,95) e, similarmente, o aumento do consumo de oxigênio de pico (20±5,9 e 16±7,3%, P = 0,69) em pacientes com SMet+AOS e SMet-AOS. A D+TF, reduziu significativamente o IAH (38±6,2 vs 18±3,9 eventos / hora, P = 0,01) e aumentou a saturação mínima de O2 (81±2,3 vs 84±1,9 %, P = 0,01) em pacientes com SMet+AOS. Durante a estimulação hipóxica, D+TF reduziu significativamente os níveis de ANSM tanto em pacientes com SMet+AOS (41±1,9 versus 33±2,0 impulsos/ min, P = 0,02) como em SMet-AOS (36±3,2 versus 28±1,7 impulsos/ min, P = 0,05). Durante a estimulação hipercápnica, D+TF reduziu significativamente os níveis de ANSM em pacientes com SMet+AOS (39±2,0 versus 30±1,1 impulsos/ min, P = 0,0005), mas não em pacientes com SMet- AOS. CONCLUSÕES. Tratamento não-farmacológico como D+TF melhora o controle quimiorreflexo periférico da ANSM em pacientes com síndrome metabólica. Esta mudança autonômica é mais pronunciada em pacientes com SMet+AOS, nos quais D+TF melhora tanto o controle quimiorreflexo periférico como o central. Além disso, D+TF melhora o distúrbio do sono em pacientes com SMet+AOS. Sendo assim, estes resultados sugerem que D+TF pode reduzir o risco cardiovascular em pacientes com SMet e AOS / INTRODUCTION. Previous studies have shown that patients with metabolic syndrome (MetS) and obstructive sleep apnea (OSA) have sympathetic hyperactivation and chemoreflex hypersensitivity. We tested the hypothesis that: 1) Hypocaloric diet associated with exercise training (D+ET) would improve chemoreflex sensitivity in patients with MetS and 2) The effects of D+ET would be more pronounced in patients with MetS+OSA than in patients without OSA (MetS-OSA). METHODS. Twenty three never treated MetS patients (ATP-III) were allocated into: 1) MetS+OSA (n=15, 53±2 yrs); and 2) MetS-OSA (n=12, 43±2 yrs). OSA was characterized by an apnea-hypopnea index (AHI) >15 events/hour (polysomnography). Muscle sympathetic nerve activity (MSNA) was evaluated by microneurography technique and blood pressure (BP) by oscillatory method. Peripheral chemoreflex sensitivity was evaluated by inhalation of 10%O2 and 90%N2 with CO2 titrated, and central chemoreflex by 7%CO2 and 93%O2 for 3 min. The hypocaloric diet was set at -500 kcal of the resting metabolic rate and exercise training extended over 4 months, 3 times/ week. RESULTS. D+ET similarly reduced body weight (5.5±0.7 and 6.2±0.6kg, P=0.44), waist circumference (WC, 5.6±1.2 and 5.4±1.0 cm, P=0.91), systolic BP (10.9±3.2 vs. 13.3±3.5 mmHg, P=0.62) and diastolic BP (8.5±1.6 vs. 8.3±1.4 mmHg, P=0.95), and similarly increased peak oxygen consumption (20±5.9 and 16±7.3%, P=0.69) in MetS+OSA and MetS-OSA patients. D+ET significantly reduced AHI (38±6.2 vs. 18±3.9 events/hour, P=0.01) and minimal O2 saturation (81±2.3 vs. 84±1.9%, P=0.01) in MetS+OSA patients. D+ET significantly reduced MSNA levels during hypoxia in MetS+OSA (41±1.9 vs. 33±2.0 bursts/min, P=0.02) and MetS-OSA (36±3.2 vs. 28±1.7 bursts/min, P=0.05) patients. D+ET significantly reduced MSNA levels during hypercapnia in MetS+OSA patients (39±2.0 vs. 30±1.1 bursts/min, P= 0.0005), but not in MetS-OSA patients. CONCLUSIONS. Non-pharmacological treatment based on D+ET improves peripheral chemoreflex control of MSNA in patients with MetS. This autonomic change is more pronounced in patients with MetS+OSA, in whom D+ET improves both peripheral and central chemoreflex controls. In addition, D+ET improves sleep disorder in patients with MetS+OSA. Altogether, these findings suggest that D+ET reduce cardiovascular risk in patients with MetS+OSA