Sleep Study
In the sleep laboratory of the Institutes of Respiratory Diseases of the University of Bari, all patients were evaluated for sleep disordered breathing during one night. They were monitored continuously for about 8 h using a portable cardiorespiratory monitoring (POLYMESAM®, MAP, Martinsried, Germany). The POLYMESAM® (PM) device consists of a recorder, to which multiple sensors are linked for the detection of the following signals: oxy-hemoglobin saturation (by a finger sensor), heart rate (derived from three electrocardiogram (ECG) electrodes placed on the chest), snoring sound (by a microphone placed on the thyroid cartilage), body posture oro-nasal airflow (by a threefold thermocouple sensor for both nostrils and mouth), and thoracic and abdominal movements (by stretch belts). Apnea was identified if the airflow was absent or nearly absent for at least 10 s. Hypopnea, was considered when there was a decrease of airflow for at least 10 seconds in respirations, a 30-percent reduction in ventilation, and a decrease in oxygen saturation.
Statistics
Data are presented as mean ± standard error (SEM) or as percentages. One-way analysis of variance (ANOVA) assessed inter-group differences. Differences between two groups were tested by Student’s t-test for unpaired data. The Chi-square test was used to compare proportions. The Pearson correlation coefficient was used for correlations. Results were considered significant at the 5% critical level (P<0.05). Statistical analyses were performed with NCSS10 Statistical Software (NCSS, LLC. Kaysville, Utah, USA).
Study Approval
Since the study was retrospective, the patients did not sign any informed consent, while the Local Ethic Committee approved the study number 1089, July the31st 2009, with note prot n. 24961/DS 03/26/2009, and approved the study number prot. N. 44696/DS 06-03-2009 n.527/DG/2004modified by the protocol n. 828/DG/2007.
Table 1