Ulm, Univ., Diss., 2008.

Regensburg, Univ., Diss., 2009.

BACKGROUND: Among patients with obstructive sleep apnea (OSA) a higher number of medical morbidities are known to be associated with those that have obesity hypoventilation syndrome (OHS) compared to OSA alone. OHS can therefore pose a higher risk of postoperative complications after elective non-cardiac surgery (NCS) and is often unrecognized at the time of surgery. The objective of this study was to retrospectively identify patients with OHS and compare their postoperative outcomes with those who have OSA alone. METHODS: Patients meeting criteria for OHS were identified within a large cohort of patients with OSA who underwent elective NCS at a major tertiary care center. We identified postoperative outcomes associated with OSA and OHS as well as the clinical determinants of OHS (BMI, AHI). Multivariable logistic or linear regression models were used for dichotomous or continuous outcomes, respectively. RESULTS: Patients with hypercapnia from definite or possible OHS, and overlap syndrome are more likely to develop postoperative respiratory failure [OR: 10.9 (95% CI 3.7-32.3), p<0.0001], postoperative heart failure (p<0.0001), prolonged intubation [OR: 5.4 (95% CI 1.9-15.7), p=0.002), postoperative ICU transfer (OR: 3.8 (95% CI 1.7-8.6), p=0.002]; longer ICU (beta coefficient: 0.86; SE: 0.32, p=0.009) and hospital length of stay (beta coefficient: 2.94; SE: 0.87, p=0.0008) when compared to patients with OSA. Among the clinical determinants of OHS, neither BMI nor AHI showed associations with any postoperative outcomes in univariable or multivariable regression. CONCLUSIONS: Better emphasis is needed on preoperative recognition of hypercapnia among patients with OSA or overlap syndrome undergoing elective NCS / Revisión por pares

Dans les sports collectifs et les sports de raquette, la capacité à répéter des sprints (repeatedsprint ability, RSA) est un facteur déterminant de la performance. L’accumulation d’efforts à haute intensité avec des récupérations souvent incomplètes mène à un état de fatigue neuromusculaire. C’est cette tolérance à la fatigue que les entraîneurs visent à améliorer avec différentes modalités d’entraînement. Avec la quête incessante d’optimisation de la performance sportive, l’ajout de stress physiologique lors des entraînements est devenu un incontournable afin de forcer les systèmes physiologiques à s’adapter. L’entraînement de la RSA en milieu hypoxique (i.e., un environnement appauvri en oxygène) permet d’améliorer ce déterminant davantage qu’un entraînement similaire effectué en normoxie. Cependant, les camps d'entraînement en altitude et/ou l'utilisation de générateurs de mélanges gazeux hypoxiques nécessitent une logistique et des équipements spécifiques qui peuvent être contraignants. La technique d’hypoventilation volontaire (VHL) permettrait de surmonter cette problématique tout en ayant des effets ergogéniques similaires. Sommairement, cette technique consiste à bloquer la respiration en fin d’expiration, puis d’effectuer un effort de haute intensité (i.e., sprints). Cependant, dans la littérature, il y a très peu de mesures physiologiques permettant d’expliquer les gains de performance à la suite de l’entraînement en VHL. De plus, les entraînements de VHL ont été jusqu’à présent très peu spécifiques aux demandes des sports collectifs. L’étude insérée dans ce mémoire a pour objectif principal de mieux comprendre les effets ergogéniques potentiels du VHL et, comme objectif secondaire, d’évaluer la faisabilité de cette technique combinée à des changements de direction à haute vitesse. Les résultats rapportés dans ce mémoire démontrent une diminution du score de détérioration de la performance lors d’un test de RSA après un entraînement VHL de 4 semaines. Les adaptations physiologiques sous-jacentes à ce gain de performance sont un meilleur maintien du recrutement des unités motrices initiales, une meilleure réoxygénation lors des périodes de récupération et une diminution de la concentration de potassium extracellulaire. La technique de VHL permet donc d’optimiser l’entraînement de la RSA tout en permettant d’introduire des changements de direction spécifiques aux demandes du sport. Des facteurs périphériques et centraux expliqueraient ces gains de performance. / In team sports and racket sports, repeated sprint ability (RSA) is a critical determinant of performance. The repetition of short and intense sprints with incomplete recovery leads to the development of neuromuscular fatigue. For coaches, the main goal of training is to improve fatigue tolerance with different training methods. In this never-ending quest for training optimisation, the use of extreme environments has become very popular among sport scientists to increase the stress placed on the athletes. Performing RSA training in hypoxia (i.e., with less oxygen) can enhance several physiological factors and thereby improve sprint endurance more than the same training performed in normoxia. However, attending a training camp at terrestrial altitude and/or using hypoxic generators requires specific logistics and equipment that can be prohibitive. The voluntary hypoventilation (VHL) technique could overcome this problem while potentially having similar ergogenic effects. Briefly, this technique consists of blocking one’s breathing at the end of a normal expiration before attempting to sprint. However, the physiological changes associated with this technique have been poorly investigated. The study presented in this thesis aimed at understanding varied physiological adaptations following VHL training, and to assess the feasibility of performing VHL during abrupt changes in direction. The current results demonstrate an improvement in sprint endurance following a 4-week VHL training. Physiological adaptations underlying this performance gain included a better maintenance of initial recruitment of motor units, greater muscle re-oxygenation during recovery periods and a decrease in extracellular potassium concentration. We conclude that the VHL technique can be successfully coupled with rapid changes of direction specific to the demands of the sport. Both peripheral and central mechanisms appear to underly these adaptations

Panic Disorder (PD) has been associated with abnormalities in the respiratory system for a long time, and treatment programs aimed at reversing these abnormalities have been developed. Panicogenic effects of biological challenges have been shown to be altered after successful treatment. Furthermore, there is evidence that anxious non-PD patients show similar responses to these challenges and hence may benefit from some kind of breathing training (BT). To test these assumptions, we recruited 45 PD patients, 39 Episodic Anxiety (EA) patients who suffered from subclinical panic attacks, and 20 non-anxious controls (NAC). Patients were randomized to one of two versions of a 4-week therapy with BT, either lower or raise end-tidal pCO2, or a waiting list (WL). Before and after treatment, participants underwent in randomized order a Voluntary Hypoventilation (VHO) test and a Voluntary Hyperventilation (VHT) test in which they were asked to either lower or raise their pCO2 while psychophysiological measures were recorded. Each test consisted of 3 segments: 1 min baseline, 3 min paced breathing, and 8 min recovery. Before treatment, PD and EA patients were more anxious, distressed, tense, and worried than NAC, and felt more dizziness, chest pain, and nausea during the laboratory assessment. However, increases in psychological symptoms or physiological sensations from baseline to the paced breathing segments were not different between groups. The two tests produced similar changes except that anxiety and dizziness increased more during the VHT than VHO. We replicated baseline breathing abnormalities previously reported for PD patients, namely greater respiration rate, tidal volume instability, and number of sighs. However, analyses did not find that patients recovered slower to either challenge. After treatment, both therapies improved on the main outcome measure. Furthermore, BT affected baseline pCO2, resulting in lower levels in the hypocapnic groups and higher levels in the hypercapnic groups without affecting any other measures. We conclude that baseline respiratory abnormalities are specific to PD. However, data suggest that the manipulations might have been too weak to elicit other previously reported group differences. Breathing training was equally effective for the lower and raise BT. Hence, factors unrelated to modifying one’s pCO2 must have accounted for the symptomatic improvement. Breathing training should not be restricted to PD but be applied to all patients suffering from anxiety attacks.

Le syndrome d'ondine est une maladie génétique rare caractérisée par une hypoventilation pendant le sommeil, des apnées et une absence de réponse au CO2. La majorité des patients ont une mutation hétérozygote à expansion d'alanine du gène PHOX2B, important dans le développement du système nerveux autonome. Notre objectif est d'étudier le rôle de Phox2b dans le contrôle de la ventilation et de valider un modèle murin du syndrome d'Ondine. Grâce à une plateforme d'exploration fonctionnelle originale permettant les mesures non invasives dans un environnement contrôlé en température et en gaz des variables cardiorespiratoires chez le souriceau, nous avons analysé in vivo deux modèles de souris hétérozygotes pour Phox2b. Les souriceaux hétérozygotes Phox2b+/-, issus d'une invalidation d'un allèle Phox2b, présentent une instabilité ventilatoire associée à une activité tonique anormalement élevée de leurs chémorécepteurs périphériques. Leur phénotype ventilatoire dépend fortement de la température ambiante. La reproduction de la mutation humaine majoritaire, une insertion de 7 alanines (souriceaux Phox2b27Ala/+) chez le souriceau, produit un phénotype similaire au syndrome d'Ondine. Ces souriceaux meurent rapidement d'apnée centrale à la naissance. Ils ont une perte spécifique de neurones exprimant de neurones du noyau rétrotrapézoïde/groupe respiratoire parafacial (RTN/pFRG) impliqués dans la chémoréception centrale et la rythmogenèse, ce qui montre le rôle important du RTN/pFRG dans la chémosensibilité au CO2, et dans la rythmogénèse respiratoire néonatale / Ondine syndrome is a rare genetic disease characterized by hypoventilation during sleep, apneas and the absence of ventilatory response to CO2. The majority of patients carry a heterozygous mutation with polyalanine expansion of PHOX2B gene, which is important in the development of autonomous nervous system. We aim to study the role of Phox2b in ventilatory control and to validate a mouse model of Ondine syndrome. We used a platform that allows in vivo, non-invasive measurements of cardiorespiratory variables in newborn mice in controlled temperature and gas conditions. Heterozygous Phox2b+/- pups, which were obtained by invalidation of one allele of Phox2b, show ventilatory instability with augmented tonic activity of peripheral chemoreceptor. Their ventilatory phenotype strongly depends on ambient temperature. Reproducing in mice Phox2b mutation, which is frequently observed in patients, an insertion of 7 alanines (mutant pups Phox2b27Ala/+) produces a similar phenotype to Ondine syndrome. These newborn mice rapidly die of central apnea after birth. Phox2b27Ala/+ pups have a specific loss of neurons expressing Phox2b in retrotrapezoïd nucleus/parafacial respiratory group (RTN/pFRG) involved in central chemoreception and in rhythmogenesis, showing the important role of RTN/pFRG in CO2 chemosensitivity, and in respiratory rhythmogenesis at birth

Panic Disorder (PD) has been associated with abnormalities in the respiratory system for a long time, and treatment programs aimed at reversing these abnormalities have been developed. Panicogenic effects of biological challenges have been shown to be altered after successful treatment. Furthermore, there is evidence that anxious non-PD patients show similar responses to these challenges and hence may benefit from some kind of breathing training (BT). To test these assumptions, we recruited 45 PD patients, 39 Episodic Anxiety (EA) patients who suffered from subclinical panic attacks, and 20 non-anxious controls (NAC). Patients were randomized to one of two versions of a 4-week therapy with BT, either lower or raise end-tidal pCO2, or a waiting list (WL). Before and after treatment, participants underwent in randomized order a Voluntary Hypoventilation (VHO) test and a Voluntary Hyperventilation (VHT) test in which they were asked to either lower or raise their pCO2 while psychophysiological measures were recorded. Each test consisted of 3 segments: 1 min baseline, 3 min paced breathing, and 8 min recovery. Before treatment, PD and EA patients were more anxious, distressed, tense, and worried than NAC, and felt more dizziness, chest pain, and nausea during the laboratory assessment. However, increases in psychological symptoms or physiological sensations from baseline to the paced breathing segments were not different between groups. The two tests produced similar changes except that anxiety and dizziness increased more during the VHT than VHO. We replicated baseline breathing abnormalities previously reported for PD patients, namely greater respiration rate, tidal volume instability, and number of sighs. However, analyses did not find that patients recovered slower to either challenge. After treatment, both therapies improved on the main outcome measure. Furthermore, BT affected baseline pCO2, resulting in lower levels in the hypocapnic groups and higher levels in the hypercapnic groups without affecting any other measures. We conclude that baseline respiratory abnormalities are specific to PD. However, data suggest that the manipulations might have been too weak to elicit other previously reported group differences. Breathing training was equally effective for the lower and raise BT. Hence, factors unrelated to modifying one’s pCO2 must have accounted for the symptomatic improvement. Breathing training should not be restricted to PD but be applied to all patients suffering from anxiety attacks.

L'hypoventilation alvéolaire chronique est considérée comme un marqueur d'évolution péjorative de différentes pathologies respiratoires. Cependant, son rôle physiopathologique dans différentes dysfonctions systémiques n'a pas été étudié de manière convaincante. Cette thèse avait pour but d'investiguer les conséquences de l'hypoventilation alvéolaire modérée au cours de l'insuffisance respiratoire chronique restrictive et les effets de son traitement par ventilation non-invasive.<br /> Nous avons montré que des patients affectés d'un syndrome obésité-hypoventilation (SOH) avaient une fonction endothéliale plus sévèrement altérée et une inflammation systémique plus importante que les patients obèses simples. La PaCO2 était corrélée à la dysfonction endothéliale (Borel et coll, manuscrit en préparation). Nous avons observé que la proportion d'hypoventilation en sommeil paradoxal, chez les sujets SOH, était associée à une réponse ventilatoire au CO2 abaissée et une somnolence diurne excessive. Pour la première fois, nous avons constaté que la ventilation non invasive nocturne améliorait la vigilance diurne objective (Chouri-Pontarollo et coll, Chest 2007). Nous menons actuellement la première étude randomisée du traitement des patients porteurs d'un SOH par VNI versus observation pendant un mois. L'analyse intermédiaire montrait qu'un mois de VNI nocturne chez les patients SOH améliorait la PaCO2 diurne, la capacité pulmonaire totale, la structure du sommeil, cependant aucun paramètre cardiovasculaire et métabolique n'était modifié. <br />Chez des patients insuffisants respiratoires chroniques pariéto-restrictifs, la VNI utilisée au cours d'un exercice aigu, augmentait la ventilation et améliorait la tolérance à l'effort (Borel et coll, Resp Med 2008). Chez ces mêmes patients, un réentrainement à l'effort sous VNI n'apportait pas de bénéfices additionnels par rapport à un réentrainement en ventilation spontanée sauf chez les patients les plus sévères. Ces derniers, amélioraient leur périmètre de marche et leur qualité de vie. Leur fatigue en particulier était améliorée s'ils s'étaient réentraînés sous VNI (Borel et coll, Am Journal of physical med and rehab, 2008, soumis). <br />Enfin, nous avons analysé l'impact des fuites intentionnelles des masques de VNI sur la performance des appareils de VNI bi-pressionnels. L'augmentation des fuites intentionnelles diminuait les capacités des appareils à atteindre et maintenir la pression de consigne. Ceci pouvait conduire à une diminution du volume délivré au patient, en particulier pour des fuites intentionnelles supérieures à 40 L.min-1 à 14 cm H2O de pression (Borel et al, Chest, sous presse). <br /> Conclusion : L'hypoventilation alvéolaire chronique peut-être considéré comme un déterminant physiopathologique de la dysfonction endothéliale, de l'inflammation, de la somnolence, et de l'intolérance à l'effort. La VNI, utilisée au cours des efforts, permet d'améliorer les capacités d'exercice et la qualité de vie des patients insuffisants respiratoires restrictifs les plus sévères. Malgré les limites technologiques des appareils de VNI bi-pressionnels utilisés actuellement, la VNI corrige l'hypoventilation alvéolaire des patients SOH, cependant les effets sur l'inflammation, la dysfonction endothéliale restent incertains à cours et long terme chez ces sujets obèses.

Introdução: A obesidade é um problema de saúde pública em crescimento, sendo o principal fator de risco para os transtornos respiratórios durante o sono (TRS), como a apneia obstrutiva do sono (AOS) e a hipoventilação noturna. A cirurgia bariátrica se consolidou como possibilidade terapêutica para a obesidade significativa. A identificação precoce dos TRS na fase pré-operatória é essencial, pois acarretam um risco aumentado de complicações perioperatórias. Diversas propostas de triagem dos TRS com abordagens mais simplificadas em relação à polissonografia (PSG) têm surgido na literatura nos últimos anos, nem todas avaliadas em uma população de pacientes obesos. Objetivo: Determinar os padrões ventilatórios em obesos candidatos à cirurgia bariátrica e avaliar três estratégias de rastreamento de TRS nessa população. Métodos: Os critérios de inclusão foram pacientes com idade ≥18 anos com obesidade graus III [índice de massa corporal (IMC) ≥40 kg/m2] ou II (IMC ≥35 kg/m2) com comorbidades relacionadas à obesidade encaminhados para avaliação para cirurgia bariátrica. Foram excluídos pacientes com cardiopatia e/ou pneumopatia graves ou descompensadas. Foram avaliados 91 pacientes através de três estratégias: (1) Clínica [Escala de Sonolência de Epworth e questionários STOP-Bang, Berlim e Sleep Apnea Clinical Score (SACS), acrescidos de gasometria arterial (GA)]; (2) Oximetria (holter de oximetria durante o sono e GA) e (3) Portátil [monitorização portátil (MP) durante o sono e capnografia)]. Todos os testes realizados foram comparados com o teste padrão, a PSG, para o diagnóstico de AOS. Resultados: A amostra estudada foi composta por 77 mulheres (84,6%) com média de idade de 44,7 ± 11,5 anos e de IMC de 50,1 ± 8,2 kg/m2. Os padrões ventilatórios identificados foram ronco, hipoxemia isolada durante o sono, AOS e hipoventilação noturna em associação com AOS. Os dados polissonográficos evidenciaram AOS em 67 de 87 pacientes (77%), sendo 26 com transtorno leve, 19 moderado e 22 grave. Vinte pacientes (23%) tiveram diagnóstico de ronco e dois deles também apresentaram hipoxemia isolada durante o sono sem AOS ou hipoventilação concomitantes. Hipoventilação noturna associada com AOS foi identificada por capnografia em um paciente. Na Estratégia Clínica, o melhor resultado alcançado foi com o escore STOP-Bang ≥6 em pacientes com índice de apneia hipopneia (IAH) ≥30 (acurácia total de 82,8%). Na Estratégia Oximetria, os pontos de corte com maior sensibilidade e especificidade para IAH ≥5, ≥10, ≥15 e ≥30 foram tempo total de registro com saturação periférica de oxigênio (SpO2) <90% por, pelo menos, 5 minutos; índice de dessaturação (ID)3% ≥22 dessaturações/hora de registro e ID4% ≥10 e ≥15 dessaturações/hora de registro. Todas as áreas sobre a curva (ASC) situaram-se acima de 0,850. Para um IAH ≥5, o ID4% ≥10 apresentou sensibilidade de 97%, especificidade de 73,7%, valor preditivo positivo de 92,8% e negativo de 87,5% e acurácia total de 91,8%. Na Estratégia Portátil, o índice de distúrbios respiratórios (IDR) foi um bom preditor de AOS nos variados pontos de corte de IAH (ASC de 0,952 a 0,995). As melhores sensibilidades e especificidades foram alcançadas em pontos de corte semelhantes de IDR e IAH, especialmente nos extratos de IAH ≥10 e ≥30. A acurácia total máxima foi de 93,9% para IDR ≥5, ≥10 e ≥30 nos seus correspondentes IAH. Baseados nesses resultados, foram testadas estratégias combinadas compostas pelo questionário STOP-Bang ≥6 com ID4% ≥10 ou ≥15. O melhor equilíbrio entre sensibilidade e especificidade e a maior acurácia foram obtidos com a estratégia STOP-Bang ≥6 com ID4% ≥15 em AOS grave. Conclusões: A frequência de ocorrência de TRS nos obesos em avaliação para cirurgia bariátrica foi alta, sendo a AOS o transtorno mais encontrado. Os questionários disponíveis até o momento, isoladamente, parecem ser insuficientes para o rastreamento de AOS nessa população, à exceção do STOP-Bang ≥6 em pacientes com AOS grave. O uso de uma medida fisiológica objetiva expressa pelo holter de oximetria foi útil para rastrear AOS em pacientes obesos. A MP apresentou acurácia aumentada, especialmente nos extremos de valores de IAH, com resultados comparáveis aos da PSG. A PSG poderia ser reservada apenas para confirmação diagnóstica em casos selecionados. / Introduction: Obesity is a growing public health problem and the main risk factor for sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA) and nocturnal hypoventilation. Bariatric surgery has become an option for the treatment of significant obesity. Early detection of SDB preoperatively is essential, since these disorders are associated with an increased risk of perioperative complications. Several screening tools for SDB, with a more simplified approach than polysomnography (PSG), have been proposed in recent years, but not all of them have been evaluated in a population of obese patients. Objective: To determine ventilatory patterns in obese candidates for bariatric surgery and evaluate three SDB screening strategies in this population. Methods: Eligible participants were all patients aged ≥18 years with grade III (body mass index [BMI] ≥ 40kg/m2) or grade II (BMI ≥35 kg/m2) obesity and obesity-related comorbidities who were referred for evaluation for bariatric surgery. Exclusion criteria were heart disease and/or severe or decompensated pulmonary disease. Ninety-one patients were evaluated by three strategies: (1) Clinical (Epworth Sleepiness Scale and STOP-Bang questionnaire, Berlin questionnaire and Sleep Apnea Clinical Score [SACS] plus blood gas analysis [BGA]); (2) Oximetry (overnight Holter-oximeter monitoring and BGA); and (3) Portable (overnight portable monitoring and capnography). All tests were compared with the gold standard, PSG, for the diagnosis of OSA. Results: The sample consisted of 77 women (84.6%) with a mean (SD) age of 44.7 (11.5) years and BMI of 50.1 (8.2) kg/m2. The ventilatory patterns identified were snoring, isolated nocturnal hypoxemia, OSA, and nocturnal hypoventilation associated with OSA. Polysomnographic data showed OSA in 67 of 87 patients (77%), 26 with mild, 19 with moderate and 22 with severe disorder. Twenty patients (23%) had a diagnosis of snoring, and two of them also had isolated nocturnal hypoxemia without concomitant OSA or hypoventilation. Nocturnal hypoventilation associated with OSA was detected by capnography in one patient. In the Clinical Strategy, the best result was obtained with the STOP-Bang score ≥6 in patients with an apnea-hypopnea index (AHI) ≥30 (overall accuracy of 82.8%). In the Oximetry Strategy, the cutoff values with the highest sensitivity and specificity for AHI ≥5, ≥10, ≥15, and ≥30 were total recording time with peripheral oxygen saturation (SpO2)< 90% for at least 5 minutes, 3% oxygen desaturation index (ODI) ≥22 desaturations/hour of recording, and 4%ODI ≥10 and ≥15 desaturations/hour of recording. All areas under the curve (AUC) were above 0.850. For AHI ≥5, 4%ODI ≥10 had a sensitivity of 97%, specificity of 73.7%, positive predictive value of 92.8%, negative predictive value of 87.5%, and overall accuracy of 91.8%. In the Portable Strategy, the respiratory disturbance index (RDI) was a good predictor of OSA in various cutoff values of AHI (AUC of 0.952 to 0.995). The highest sensitivity and specificity were obtained at similar cutoff values for RDI and AHI, especially for AHI ≥10 and ≥30. The maximum overall accuracy was 93.9% for RDI ≥5, ≥10, and ≥30 in their corresponding AHI. Based on these results, combined strategies were tested consisting of the STOP-Bang score ≥6 combined with 4%ODI ≥10 or ≥15. The best balance between sensibility and specificity and the maximum accuracy were achieved with the strategy composed by STOP-Bang ≥6 and 4%ODI ≥15 in patients with severe OSA. Conclusions: The frequency of occurrence of SDB in obese individuals undergoing evaluation for bariatric surgery was high, and OSA was the most frequent occurrence. Currently available questionnaires were insufficient to screen for OSA in this population, with the exception for the STOP-Bang score ≥6 in patients with severe OSA. The use of an objective physiological measure, such as Holter-oximetry monitoring, was useful as a screening tool for OSA in obese patients. Portable monitoring showed increased accuracy, especially in extreme AHI values, with results comparable to those obtained with PSG. The PSG could be reserved only for certain cases where diagnostic confirmation is necessary.

Introdução: A obesidade é um problema de saúde pública em crescimento, sendo o principal fator de risco para os transtornos respiratórios durante o sono (TRS), como a apneia obstrutiva do sono (AOS) e a hipoventilação noturna. A cirurgia bariátrica se consolidou como possibilidade terapêutica para a obesidade significativa. A identificação precoce dos TRS na fase pré-operatória é essencial, pois acarretam um risco aumentado de complicações perioperatórias. Diversas propostas de triagem dos TRS com abordagens mais simplificadas em relação à polissonografia (PSG) têm surgido na literatura nos últimos anos, nem todas avaliadas em uma população de pacientes obesos. Objetivo: Determinar os padrões ventilatórios em obesos candidatos à cirurgia bariátrica e avaliar três estratégias de rastreamento de TRS nessa população. Métodos: Os critérios de inclusão foram pacientes com idade ≥18 anos com obesidade graus III [índice de massa corporal (IMC) ≥40 kg/m2] ou II (IMC ≥35 kg/m2) com comorbidades relacionadas à obesidade encaminhados para avaliação para cirurgia bariátrica. Foram excluídos pacientes com cardiopatia e/ou pneumopatia graves ou descompensadas. Foram avaliados 91 pacientes através de três estratégias: (1) Clínica [Escala de Sonolência de Epworth e questionários STOP-Bang, Berlim e Sleep Apnea Clinical Score (SACS), acrescidos de gasometria arterial (GA)]; (2) Oximetria (holter de oximetria durante o sono e GA) e (3) Portátil [monitorização portátil (MP) durante o sono e capnografia)]. Todos os testes realizados foram comparados com o teste padrão, a PSG, para o diagnóstico de AOS. Resultados: A amostra estudada foi composta por 77 mulheres (84,6%) com média de idade de 44,7 ± 11,5 anos e de IMC de 50,1 ± 8,2 kg/m2. Os padrões ventilatórios identificados foram ronco, hipoxemia isolada durante o sono, AOS e hipoventilação noturna em associação com AOS. Os dados polissonográficos evidenciaram AOS em 67 de 87 pacientes (77%), sendo 26 com transtorno leve, 19 moderado e 22 grave. Vinte pacientes (23%) tiveram diagnóstico de ronco e dois deles também apresentaram hipoxemia isolada durante o sono sem AOS ou hipoventilação concomitantes. Hipoventilação noturna associada com AOS foi identificada por capnografia em um paciente. Na Estratégia Clínica, o melhor resultado alcançado foi com o escore STOP-Bang ≥6 em pacientes com índice de apneia hipopneia (IAH) ≥30 (acurácia total de 82,8%). Na Estratégia Oximetria, os pontos de corte com maior sensibilidade e especificidade para IAH ≥5, ≥10, ≥15 e ≥30 foram tempo total de registro com saturação periférica de oxigênio (SpO2) <90% por, pelo menos, 5 minutos; índice de dessaturação (ID)3% ≥22 dessaturações/hora de registro e ID4% ≥10 e ≥15 dessaturações/hora de registro. Todas as áreas sobre a curva (ASC) situaram-se acima de 0,850. Para um IAH ≥5, o ID4% ≥10 apresentou sensibilidade de 97%, especificidade de 73,7%, valor preditivo positivo de 92,8% e negativo de 87,5% e acurácia total de 91,8%. Na Estratégia Portátil, o índice de distúrbios respiratórios (IDR) foi um bom preditor de AOS nos variados pontos de corte de IAH (ASC de 0,952 a 0,995). As melhores sensibilidades e especificidades foram alcançadas em pontos de corte semelhantes de IDR e IAH, especialmente nos extratos de IAH ≥10 e ≥30. A acurácia total máxima foi de 93,9% para IDR ≥5, ≥10 e ≥30 nos seus correspondentes IAH. Baseados nesses resultados, foram testadas estratégias combinadas compostas pelo questionário STOP-Bang ≥6 com ID4% ≥10 ou ≥15. O melhor equilíbrio entre sensibilidade e especificidade e a maior acurácia foram obtidos com a estratégia STOP-Bang ≥6 com ID4% ≥15 em AOS grave. Conclusões: A frequência de ocorrência de TRS nos obesos em avaliação para cirurgia bariátrica foi alta, sendo a AOS o transtorno mais encontrado. Os questionários disponíveis até o momento, isoladamente, parecem ser insuficientes para o rastreamento de AOS nessa população, à exceção do STOP-Bang ≥6 em pacientes com AOS grave. O uso de uma medida fisiológica objetiva expressa pelo holter de oximetria foi útil para rastrear AOS em pacientes obesos. A MP apresentou acurácia aumentada, especialmente nos extremos de valores de IAH, com resultados comparáveis aos da PSG. A PSG poderia ser reservada apenas para confirmação diagnóstica em casos selecionados. / Introduction: Obesity is a growing public health problem and the main risk factor for sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA) and nocturnal hypoventilation. Bariatric surgery has become an option for the treatment of significant obesity. Early detection of SDB preoperatively is essential, since these disorders are associated with an increased risk of perioperative complications. Several screening tools for SDB, with a more simplified approach than polysomnography (PSG), have been proposed in recent years, but not all of them have been evaluated in a population of obese patients. Objective: To determine ventilatory patterns in obese candidates for bariatric surgery and evaluate three SDB screening strategies in this population. Methods: Eligible participants were all patients aged ≥18 years with grade III (body mass index [BMI] ≥ 40kg/m2) or grade II (BMI ≥35 kg/m2) obesity and obesity-related comorbidities who were referred for evaluation for bariatric surgery. Exclusion criteria were heart disease and/or severe or decompensated pulmonary disease. Ninety-one patients were evaluated by three strategies: (1) Clinical (Epworth Sleepiness Scale and STOP-Bang questionnaire, Berlin questionnaire and Sleep Apnea Clinical Score [SACS] plus blood gas analysis [BGA]); (2) Oximetry (overnight Holter-oximeter monitoring and BGA); and (3) Portable (overnight portable monitoring and capnography). All tests were compared with the gold standard, PSG, for the diagnosis of OSA. Results: The sample consisted of 77 women (84.6%) with a mean (SD) age of 44.7 (11.5) years and BMI of 50.1 (8.2) kg/m2. The ventilatory patterns identified were snoring, isolated nocturnal hypoxemia, OSA, and nocturnal hypoventilation associated with OSA. Polysomnographic data showed OSA in 67 of 87 patients (77%), 26 with mild, 19 with moderate and 22 with severe disorder. Twenty patients (23%) had a diagnosis of snoring, and two of them also had isolated nocturnal hypoxemia without concomitant OSA or hypoventilation. Nocturnal hypoventilation associated with OSA was detected by capnography in one patient. In the Clinical Strategy, the best result was obtained with the STOP-Bang score ≥6 in patients with an apnea-hypopnea index (AHI) ≥30 (overall accuracy of 82.8%). In the Oximetry Strategy, the cutoff values with the highest sensitivity and specificity for AHI ≥5, ≥10, ≥15, and ≥30 were total recording time with peripheral oxygen saturation (SpO2)< 90% for at least 5 minutes, 3% oxygen desaturation index (ODI) ≥22 desaturations/hour of recording, and 4%ODI ≥10 and ≥15 desaturations/hour of recording. All areas under the curve (AUC) were above 0.850. For AHI ≥5, 4%ODI ≥10 had a sensitivity of 97%, specificity of 73.7%, positive predictive value of 92.8%, negative predictive value of 87.5%, and overall accuracy of 91.8%. In the Portable Strategy, the respiratory disturbance index (RDI) was a good predictor of OSA in various cutoff values of AHI (AUC of 0.952 to 0.995). The highest sensitivity and specificity were obtained at similar cutoff values for RDI and AHI, especially for AHI ≥10 and ≥30. The maximum overall accuracy was 93.9% for RDI ≥5, ≥10, and ≥30 in their corresponding AHI. Based on these results, combined strategies were tested consisting of the STOP-Bang score ≥6 combined with 4%ODI ≥10 or ≥15. The best balance between sensibility and specificity and the maximum accuracy were achieved with the strategy composed by STOP-Bang ≥6 and 4%ODI ≥15 in patients with severe OSA. Conclusions: The frequency of occurrence of SDB in obese individuals undergoing evaluation for bariatric surgery was high, and OSA was the most frequent occurrence. Currently available questionnaires were insufficient to screen for OSA in this population, with the exception for the STOP-Bang score ≥6 in patients with severe OSA. The use of an objective physiological measure, such as Holter-oximetry monitoring, was useful as a screening tool for OSA in obese patients. Portable monitoring showed increased accuracy, especially in extreme AHI values, with results comparable to those obtained with PSG. The PSG could be reserved only for certain cases where diagnostic confirmation is necessary.