Effects of individualised lung-protective ventilation with lung dynamic compliance-guided positive end-expiratory pressure titration on postoperative pulmonary complications of paediatric video-assisted thoracoscopic surgery: protocol for a randomised controlled trial.

INTRODUCTION: Lung-protective ventilation strategies (LPVS) for one-lung ventilation (OLV) in paediatric patients pose greater challenges than in adults. Optimising LPVS for paediatric OLV to mitigate postoperative pulmonary complications (PPCs) has emerged as a current research focal point. However, there remains a divergence of opinions concerning the individualised setting and application of positive end-expiratory pressure (PEEP). Lung dynamic compliance (Cdyn) can serve as a reflection of the lung's physiological state in children during OLV and is a readily obtainable parameter. This study protocol is formulated to assess the effectiveness of Cdyn-guided PEEP titration on PPCs during paediatric OLV. METHODS AND ANALYSIS: This study constitutes a single-centre, prospective, double-blind, randomised controlled trial. The trial aims to recruit 60 paediatric patients scheduled for video-assisted thoracoscopic surgery. These eligible patients will be randomly assigned to either the Cdyn-guided PEEP group or the conventional PEEP group during general anaesthesia for OLV. The primary outcome will involve assessing the incidence of PPCs at 7 days after surgery. Secondary outcomes will encompass the evaluation of the modified lung ultrasound score following surgery, as well as monitoring the oxygenation index, driving pressure and Cdyn during mechanical ventilation. Data collection will be performed by investigators who are kept blinded to the interventions. ETHICS AND DISSEMINATION: The Clinical Trial Ethics Committee at Shenzhen Children's Hospital has conferred ethical approvals for this trial (approval number: 2022076). Results from this trial will be disseminated in peer-reviewed journals and presented at professional symposiums. TRAIL REGISTRATION NUMBER: NCT05386901.

Monitoring dynamics of Kyagar Glacier surge and repeated draining of Ice-dammed lake using multi-source remote sensing.

Glacier surges, a primary factor contributing to various glacial hazards, has long captivated the attention of the global glaciological community. This study delves into the dynamics of Kyagar Glacier surging and the associated drainage features of its Ice-dammed lake, employing high temporal resolution optical imagery. Our findings indicate that the surge on Kyagar Glacier began in late spring and early summer of 2014 and concluded during the summer of 2016. This surge resulted in the transfer of 0.321 ± 0.012 km3 of glacier mass from the reservoir zone to the receiving zone, leading to the formation of an ice-dammed lake at the glacier's terminus. The lake experienced five outbursts between 2015 and 2019, with the largest discharge occurring in 2017. And the maximum water depth during this period was 112 ± 11 m, resulting in a water storage volume of (158.37 ± 28.32) × 106 m3. On the other hand, our analysis of the relationship between glacier surface velocity and albedo, coupled with an examination of subglacial dynamics, revealed that increased precipitation during the active phase of the Kyagar Glacier results in accumulation of mass in the upper glacier. This accumulation induces changes in basal shear stress, triggering the glacier's transition into an unstable state. Consequently, glacier deformation rates escalate, surface crevasses proliferate, potentially providing conduits for surface meltwater to infiltrate the glacier bed. This, in turn, leaded to elevated basal water pressure, initiating glacier sliding. Furthermore, we postulated that the repetitive drainage of Kyagar Ice-dammed lake was primarily influenced by the opening and closing of subglacial drainage pathways and variations in inflow volumes. Future endeavors necessitate rigorous field observations to enhance glacier surge simulations, deepening our comprehension of glacier surge mechanisms and mitigating the impact of associated glacial hazards.