Luciane Mello-Fujita

Does Obstructive Sleep Apnea Impair the Cardiopulmonary Response to Exercise

STUDY OBJECTIVES The aim of this study was to evaluate cardiopulmonary exercise performance in lean and obese patients with obstructive sleep apnea (OSA) compared with controls. DESIGN Case-control study. SETTING The study was carried out in Sao Paulo Sleep Institute, Sao Paulo, Brazil. PATIENTS AND PARTICIPANTS INDIVIDUALS WITH SIMILAR AGES WERE ALLOCATED INTO GROUPS: 22 to the lean OSA group, 36 to the lean control group, 31 to the obese OSA group, and 26 to the obese control group. INTERVENTIONS The participants underwent a clinical evaluation, polysomnography, a maximum limited symptom cardiopulmonary exercise test, two-dimensional transthoracic echocardiography, and spirometry. MEASUREMENTS AND RESULTS The apnea-hypopnea index, arousal index, lowest arterial oxygen saturation (SaO2) and time of SaO2 < 90% were different among the groups. There were differences in functional capacity based on the following variables: maximal oxygen uptake (VO2max), P < 0.01 and maximal carbon dioxide production (VCO2max), P < 0.01. The obese patients with OSA and obese controls presented significantly lower VO2max and VCO2max values. However, the respiratory exchange ratio (RER) and anaerobic threshold (AT) did not differ between groups. Peak diastolic blood pressure (BP) was higher among the obese patients with OSA but was not accompanied by changes in peak systolic BP and heart rate (HR). When multiple regression was performed, body mass index (P < 0.001) and male sex in conjunction with diabetes (P < 0.001) independently predicted VO2max (mL/kg/min). CONCLUSIONS The results of this study suggest that obesity alone and sex, when associated with diabetes but not OSA, influenced exercise cardiorespiratory function.

Treatment of obstructive sleep apnea syndrome associated with stroke

The association between sleep-disordered breathing and stroke has been a subject of increased interest and research. Obstructive sleep apnea (OSA) is an important risk factor for stroke incidence and mortality. Moreover, OSA is a common clinical outcome after stroke, directly influencing the patients recovery. The treatment of choice for OSA is positive airway pressure (PAP) support and the PAP appliance is considered the most recommended clinical management for the treatment of patients with cardiovascular complications. However, the implementation of PAP in stroke patients remains a challenge, considering the increased frequency of motor and language impairments associated with the cerebrovascular event. In the present study, we reviewed the main findings describing the association between stroke and OSA treatment with continuous positive airway pressure. We also discussed the types of OSA treatment, the different options and indications of PAP treatment, PAP adherence and the clinical outcomes after treatment.

Cardiorespiratory response to exercise in men and women with obstructive sleep apnea

BACKGROUND OSA severity has been associated with self-reported lack of exercise. Most of the research has been done with men recruited from sleep clinics. There is limited data on the exercise performance of women with OSA. Therefore, the aim of this study was to assess exercise performance in a prospective, consecutive sample of men and women with OSA to compare their cardio respiratory parameters, arterial blood pressure and heart rate responses during and after exercise. METHODS Sixty-two subjects (32 men) completed the protocol. Men had a higher peak VO2, percent predicted peak VO2, VCO2, heart rate, systolic BP, and oxygen pulse than women. RESULTS There were no differences between men and women for peak oxygen saturation, peak Borg scales for dyspnea and leg fatigue and diastolic BP. A significant negative correlation was found between severity of OSA as measured by AHI, and peak VO2 (r=-0.4) in women, but not in men. CONCLUSION Men with OSA have higher peak VO2 and higher peak exercise heart rate than women with OSA; they also have higher end-exercise systolic BP than women and higher SBP during recovery from exercise; although this difference is not significant when adjusted for peak systolic BP. In men with OSA, there is no correlation between peak VO2 and AHI, but there is a significant correlation between these variables in women. Heart rate and blood pressure behaved similarly during exercise in both groups.

The influence of nasal abnormalities in adherence to continuous positive airway pressure device therapy in obstructive sleep apnea patients. What role does the nose play

The role of the nose in obstructive sleep apnea (OSA) is a controversial topic in the literature. The comments made regarding the pathophysiology that exists between the nose and OSA are relevant and important. However, prior research shows that the treatment of nasal abnormalities can improve sleep quality but has limited impact on improvement of OSA. With regard to adherence to air pressure devices, there is a consensus in the literature that nasal surgery is able to decrease therapeutic continuous positive airway pressure (CPAP) pressure [1–4], which could make its use more comfortable and improve adherence. But in fact, only one study showed a significant mean increase of 48.6 min in use of CPAP after surgery [4]. Studies following nasal surgery that measure mediumand long-term adherence are still needed. Another relevant point is that the role of the nose on adherence to CPAP is controversial in the literature. Tarrega et al. [5] found no association between the findings of rhinomanometry and adherence to CPAP, demonstrating results similar to those found by Haddad et al. [6]. On the other hand, Morris et al. [7] and Sugiura et al. [8] found associations between nasal findings and CPAP adherence. So et al. [9] found an association when evaluating patients with a lower apnea-hyponea index, but found no association for the whole group of study subjects. There are two main factors that limit the ability to demonstrate the role of the nose on adherence to CPAP. One is the difficulty in determining an ideal method for the evaluation of nasal function [10]. A second is the fact that adherence to CPAP is multifactorial and not solely dependent upon nasal matters. Further studies that evaluate the nasal function of patients who are non-adherent to CPAP are needed. Adherence to any kind of treatment depends on the sum of the individual approaches to many small factors, and the nose is one of them.

Evaluation and Validation of a Method for Determining Platelet Catecholamine in Patients with Obstructive Sleep Apnea and Arterial Hypertension

Background Measurements of plasma and urinary catecholamine are susceptible to confounding factors that influence the results, complicating the interpretation of sympathetic nervous system (SNS) activity in the Obstructive sleep apnea (OSA) and arterial hypertension (HYP) conditions. Objective In this study, we validated a test for platelet catecholamine and compared the catecholamine levels (adrenaline and noradrenaline) in urine, plasma and platelets in patients with OSA and HYP compared with controls. Methods In the validation, 30 healthy, nonsmoking volunteers who were not currently undergoing treatment or medication were selected as the control group. One hundred fifty-four individuals (114 OSA, 40 non-OSA) were consecutively selected from the outpatient clinic of the Sleep Institute and underwent clinical, polysomnographic and laboratory evaluation, including the urinary, plasma and platelet levels of adrenaline (AD) and noradrenaline (NA). Patients were then allocated to groups according to the presence of OSA and/or hypertension. Results A logistic regression model, controlled for age and BMI, showed that urinary AD and urinary NA were risk factors in the OSA+HYP group and the HYP group; however, the model showed higher levels of platelet NA for OSA without HYP. After 1 year of CPAP (continuous upper airway pressure) treatment, patients (n = 9) presented lower levels of urinary NA (p = 0.04) and platelet NA (p = 0.05). Conclusion Urinary NA and AD levels were significantly associated with the condition of hypertension with and without OSA, whereas platelet NA with OSA without comorbidity. These findings suggest that platelet catecholamine levels might reflect nocturnal sympathetic activation in OSA patients without hypertension.