Non-Invasive Ventilation (NIV) and Homeostatic Model Assessment (HOMA) Index in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients with Chronic Hypercapnic Respiratory Failure: A Pilot Study.

The effects of Non-invasive Ventilation (NIV) on Insulin Resistance (IR) in stable Chronic Obstructive Pulmonary Disease (COPD) patients have not been fully explored. The aim of this study was to assess the effects of NIV on IR and adiponectin levels during one year application of NIV in stable COPD patients with Chronic Hypercapnic Respiratory Failure. Twenty-five (25) stable COPD patients with Chronic Hypercapnic Respiratory Failure and with no self-reported comorbidities completed the study. NIV was administered in the spontaneous/timed mode via a full face mask using a bi-level positive airway pressure system. Spirometry, blood pressure, arterial blood gases, dyspnea, daytime sleepiness, serum fasting glucose and insulin levels were assessed. IR was assessed with the calculation of the Homeostatic Model Assessment (HOMA) index. Adiponectin was measured with radioimmunoassay. Study participants were re-evaluated on the first, third, sixth, ninth and twelfth month after the initial evaluation. There was a significant improvement in FEV1 values from the first month (34.1 ± 11.6% vs 37 ± 12.3%, p = 0.05). There was a significant decrease in IR by the ninth month of NIV use (3.4 ± 2.3 vs 2.2 ± 1.4, p < 0.0001), while adiponectin levels significantly improved from the first month of NIV use. Stepwise regression analysis revealed that baseline HOMA index was associated with paCO2 (ß = 0.07 ± 0.02, p = 0.001), while baseline adiponectin levels were associated with FVC (ß = 0.05 ± 0.02, p = 0.035) and the concentration of serum bicarbonate (HCO3-) (-ß = 0.18 ± 0.06, p = 0.002). Insulin sensitivity and glucose metabolism as well as adiponectin levels improved along with the improvements in respiratory failure.

Noninvasive ventilation in chronic respiratory failure: effects on quality of life.

BACKGROUND: Noninvasive ventilation (NIV) has been found to be an essential technique to treat chronic respiratory failure (CRF) resulting from restrictive thoracic disorders (RTD). The last decades were characterized by the expansion of NIV to treat patients suffering from various other conditions, such as chronic obstructive pulmonary disease (COPD) and obesity hypoventilation syndrome (OHS). OBJECTIVES: The aim of this study was to evaluate the effect of NIV on health-related quality of life (HRQoL) of patients with CRF during 2 years and to identify parameters associated with changes in HRQoL. METHODS: Ninety-one patients with CRF [35 COPD; 17 RTD; 28 OHS; 11 neuromuscular diseases (NMD)] participated. HRQoL was assessed with the SF-36 questionnaire. Additional measurements included blood gases, pulmonary function tests, dyspnea, daytime sleepiness, exacerbations and hospitalizations. The patients were evaluated every 3-6 months. RESULTS: Improvements in SF-36 physical component summary (PCS, p < 0.0001) and mental component summary (MCS, p < 0.0001) scores in RTD and MCS in OHS (p = 0.01) and COPD (p = 0.003) were observed by the third month. PCS in OHS and COPD patients improved by the sixth month (p = 0.003 and p < 0.0001, respectively). NMD patients did not present improvements in HRQoL. Improvements in HRQoL were associated with improvements in PaO(2) and dyspnea in COPD patients, and with total hours of daily ventilator use, improvement in dyspnea, pressure support and expiratory positive airway pressure in RTD patients. CONCLUSION: Home NIV is consistently effective in improving HRQoL and physiological parameters in patients with CRF. Randomized trials to identify subgroups of COPD responders are justified by our results.

Age, Body Mass Index, and Daytime and Nocturnal Hypoxia as Predictors of Hypertension in Patients With Obstructive Sleep Apnea.

A growing body of evidence links obstructive sleep apnea (OSA) with hypertension. The authors performed a retrospective cohort study using the University Hospital of Larissa Sleep Apnea Database (1501 patients) to determine predictors of in-laboratory diagnosed OSA for development of hypertension. Differences in continuous variables were assessed via independent samples t test, whereas discrete variables were compared by Pearson's chi-square test. Multivariate analysis was performed via discriminant function analysis. There were several significant differences between hypertensive and normotensive patients. Age, body mass index, comorbidity, daytime oxygen saturation, and indices of hypoxia during sleep were deemed the most accurate predictors of hypertension, whereas apnea-hypopnea index and desaturation index were not. The single derived discriminant function was statistically significant (Wilk's lambda=0.771, χ(2) =289.070, P<.0001). Daytime and nocturnal hypoxia as consequences of chronic intermittent hypoxia play a central role in OSA-related hypertension and should be further evaluated as possible severity markers in OSA.