Diagnostic accuracy of home-based monitoring system in morbidly obese patients with high risk for sleep apnea.

BACKGROUND: No previous studies have validated the use of portable monitoring (PM) for the diagnosis of obstructive sleep apnea (OSA) in morbidly obese individuals. Our aim was to investigate the accuracy of PM for detecting respiratory events in morbidly obese patients that will be undergoing bariatric surgery. METHODS: This was a prospective study involving patients with body mass index (BMI) ≥35 kg/m(2) who were recruited from the Sleep Clinic of Universidade Federal de São Paulo. Sleep-disordered breathing (SDB) was evaluated during full-night polysomnography (PSG). PM use was randomized and used on two consecutive nights: (1) at home (STDHome) and (2) at the sleep laboratory with PSG (PSG_STDLab). RESULTS: Although 58 participants initially underwent the recordings, 26 (45%) were excluded because of technical problems. The patients' mean age was 42.9 ± 10.9 (SD) years, and 56% were female. The mean BMI was 40.8 ± 5.2 kg/m(2). All patients had high risk for OSA, as defined by the Stop-Bang questionnaire, and the mean apnea-hypopnea index (AHI) was 46.9 ± 30.4/h. The intraclass coefficient of the correlation between AHI_PSG and AHI_STDLab was r = 0.92 (p = 0.0001); the intraclass coefficient for AHI_PSG and AHI_STDHome was r = 0.84 (p = 0.0001). The Kappa index was 0.87 (p > 0.0001) for severe cases. The sensitivity and the positive predictive value increased with the disease severity. A Bland-Altman analysis showed good agreement between the investigated methods. CONCLUSIONS: PM is an efficacious method for diagnosing OSA in obese patients who have a high clinical probability of the disease. The method displays good sensitivity and specificity in severe cases; nevertheless, the high rate of data loss must be taken into account.

The use of portable monitoring for sleep apnea diagnosis in adults.

Due to increasing demand for sleep services, there has been growing interest in ambulatory models of care for patients with obstructive sleep apnea (OSA). The implementation of alternative approaches to the current management by full polysomnography (PSG) in the sleep laboratory is necessary for diagnosing this syndrome due to the high cost of full-night PSG. A good alternative option for OSA diagnosis is portable monitoring (PM), which is known for its accuracy, ease of management and lower cost when compared with full PSG. PM has not been well validated for OSA diagnosis in patients with medical comorbidities or in elderly individuals and children. PM may be recommended as an alternative method to PSG for patients with high clinical risk for OSA. In the present review, we describe the use of PM for OSA diagnosis and evaluate the current progress, costs, limitations and applications of these devices in various groups of patients, particularly for patients with comorbid diseases.

Optimizing the evaluation of excess exercise ventilation for prognosis assessment in pulmonary arterial hypertension.

BACKGROUND: Increased ventilatory (.VE) response to carbon dioxide output (.VCO2) is a key finding of incremental cardiopulmonary exercise testing in both heart failure and pulmonary arterial hypertension (PAH). As with heart failure, measures of excessive exercise ventilation considering high-to-peak exercise .VE-VCO2 might have higher prognostic relevance than those restrained to sub-maximal exercise in PAH. DESIGN: Cross-sectional and observational study on a tertiary center. METHODS: Eighty-four patients (36 idiopathic and 48 with associated conditions) were followed up for up to five years. Excessive exercise ventilation was calculated as a slope (Δ .VE/Δ .VCO2 to the respiratory compensation point (RCP) and to exercise cessation (PEAK)) and as a ratio (.VE-VCO2 at the anaerobic threshold (AT) and at PEAK). RESULTS: Thirteen patients died and three had atrial septostomy. Multivariable regression analyses revealed that Δ .VE/Δ .VCO2(PEAK) <55 and .VE/.VCO2(PEAK) <57 were better related to prognosis than Δ .VE/Δ .VCO2(RCP) and .VE/.VCO2(AT) (p < 0.01). Δ oxygen uptake (.VO2)/Δ work rate >5.5 ml/min per W was the only other independent prognostic index. According to a Kaplan-Meier survival analysis, 96.9% (90.8% to 100%) of patients showing Δ .VE/Δ .VCO2(PEAK) <55 and Δ .VO2/Δ work rate >5.5 ml/min per W were free from a PAH-related event. In contrast, 74.7% (70.1% to 78.2%) with both parameters outside these ranges had a negative outcome. CONCLUSION: Measurements of excessive exercise ventilation which consider all data points maximize the usefulness of incremental cardiopulmonary exercise testing in the prognosis evaluation of PAH.

Factors influencing physical functional status in intensive care unit survivors two years after discharge.

BACKGROUND: Studies suggest that in patients admitted to intensive care units (ICU), physical functional status (PFS) improves over time, but does not return to the same level as before ICU admission. The goal of this study was to assess physical functional status two years after discharge from an ICU and to determine factors influencing physical status in this population. METHODS: The study reviewed all patients admitted to two non-trauma ICUs during a one-year period and included patients with age ≥ 18 yrs, ICU stay ≥ 24 h, and who were alive 24 months after ICU discharge. To assess PFS, Karnofsky Performance Status Scale scores and Lawton-Instrumental Activities of Daily Living (IADL) scores at ICU admission (K-ICU and L-ICU) were compared to the scores at the end of 24 months (K-24mo and L-24mo). Data at 24 months were obtained through telephone interviews. RESULTS: A total of 1,216 patients were eligible for the study. Twenty-four months after ICU discharge, 499 (41.6%) were alive, agreed to answer the interview, and had all hospital data available. PFS (K-ICU: 86.6 ± 13.8 vs. K-24mo: 77.1 ± 19.6, p < 0.001) and IADL (L-ICU: 27.0 ± 11.7 vs. L-24mo: 22.5 ± 11.5, p < 0.001) declined in patients with medical and unplanned surgical admissions. Most strikingly, the level of dependency increased in neurological patients (K-ICU: 86 ± 12 vs. K-24mo: 64 ± 21, relative risk [RR] 2.6, 95% CI, 1.8-3.6, p < 0.001) and trauma patients (K-ICU: 99 ± 2 vs. K-24mo: 83 ± 21, RR 2.7, 95% CI, 1.6-4.6, p < 0.001). The largest reduction in the ability to perform ADL occurred in neurological patients (L-ICU: 27 ± 7 vs. L-24mo: 15 ± 12, RR 3.3, 95% CI, 2.3-4.6 p < 0.001), trauma patients (L-ICU: 32 ± 0 vs. L-24mo: 25 ± 11, RR 2.8, 95% CI, 1.5-5.1, p < 0.001), patients aged ≥ 65 years (RR 1.4, 95% CI, 1.07-1.86, p = 0.01) and those who received mechanical ventilation for ≥ 8 days (RR 1.48, 95% CI, 1.02-2.15, p = 0.03). CONCLUSIONS: Twenty-four months after ICU discharge, PFS was significantly poorer in patients with neurological injury, trauma, age ≥ 65 tears, and mechanical ventilation ≥ 8 days. Future studies should focus on the relationship between PFS and health-related quality of life in this population.