Effects of CPAP and Mandibular Advancement Devices on depressive symptoms in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials.

PURPOSE: Studies show that patients with obstructive sleep apnea (OSA) are more likely than the general population to have psychological disorders such as depression. However, it is less clear how OSA treatment affects this association. This meta-analysis aimed to assess whether or not continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) reduce depression symptoms in patients with OSA. METHODS: We searched Pubmed, Embase, Web of Science, and Cochrane Library from creating the databases until November 2022. Our analysis included RCTs that examined CPAP and MAD treatment effectiveness for depression in patients with OSA. RESULTS: We identified 17 CPAP studies comprising 1,931 patients for inclusion in the meta-analysis. The results of the meta-analysis using a fixed effects model found that CPAP improved depressed mood in patients with OSA relative to controls (SMD = 0.27;95% CI:0.18,0.36), with small heterogeneity among trials (I2 = 8.1% < 50%, P = 0.359). We performed subgroup analyses on three factors: the length of trial follow-up, patient adherence data, and depression assessment scales. The meta-analysis also identified six MAD studies involving 315 patients. According to this analysis, there was no heterogeneity between studies (I2 = 0%, P = 0.748). MADs did not significantly improve depression symptoms compared to controls, indicating a combined effect of SMD = 0.07 (95% CI: - 0.15,0.29), P > 0.05. CONCLUSION: The present findings confirm that CPAP may improve depressive symptoms in patients with OSA. However, the review results suggest that MADs have no significant effect on depressive symptoms in patients with OSA, a finding that is different from the results of previous meta-analyses.

Numerical Investigation of Enhanced Heat Transfer with Micro Pin Fins in Heat Exchangers.

Pin-fin and flat-tube heat exchangers (PFFTHXs) offer a promising alternative to traditional louvered-fin and flat-tube heat exchangers (LFFTHXs), especially when used as evaporators. The streamlined structure of pin fins helps to effectively remove condensate and defrost water. In this study, we conducted a numerical analysis of 60 different pin-fin configurations across three pin diameters to enhance heat transfer in PFFTHXs. Our investigation focused on how pin pitch affects both airflow and heat transfer efficiency. The results show that a closer pin pitch increases both the heat transfer rate per unit area and the pressure drop for a given airflow velocity. We evaluated the overall performance of these configurations using the heat transfer rate per unit frontal area obtained at equivalent fan power levels. The analysis identified optimal configurations for each pin diameter, with the 0.2 mm diameter configuration demonstrating the highest heat transfer efficiency-this was on par with louvered fins but used fewer resources. This makes it an ideal choice for evaporative applications in PFFTHXs.