Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2020
Meta AnalysisPerioperative Lung Protection: General Mechanisms and Protective Approaches.
Postoperative pulmonary complications (PPCs) are one of the most important cause of perioperative morbidity and mortality in patients undergoing noncardiothoracic surgery, leading to increased hospital length of stay and mortality rate. The principal purpose of this review is to provide an overview of the perioperative lung protection strategies in patients undergoing elective noncardiothoracic surgery, informing clinicians on evidence-based perioperative care pathways. We also conducted a systematic review and meta-analysis of randomized controlled trials in noncardiothoracic surgery focusing on the following aspects: preoperative physiotherapy, intraoperative protective mechanical ventilation, postoperative prophylactic continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC), and postoperative physiotherapy. ⋯ Lung-protective strategies should be considered throughout the entire perioperative period. The prophylactic use of strategies initiated in the postoperative period only, such as physiotherapy, CPAP, or HFNC, offers limited benefits. Physiotherapy and patient training should be started early in the preoperative phase, and intraoperative protective mechanical ventilation should be titrated on an individual basis taking into account all the available evidence.
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The bispectral index (BIS) monitor has been available for clinical use for >20 years and has had an immense impact on academic activity in Anesthesiology, with >3000 articles referencing the bispectral index. Despite attempts to infer its algorithms by external observation, its operation has nevertheless remained undescribed, in contrast to the algorithms of other less commercially successful monitors of electroencephalogram (EEG) activity under anesthesia. With the expiration of certain key patents, the time is therefore ripe to examine the operation of the monitor on its own terms through careful dismantling, followed by extraction and examination of its internal software. ⋯ This article demonstrates that the electronic design of the A-2000 BIS Monitor does not pose any insuperable obstacles to retrieving its device software in hexadecimal machine code form directly from the motherboard. This software can be reverse engineered through disassembly and decompilation to reveal the methods by which the BIS monitor implements its algorithms, which ultimately must form the definitive statement of its function. Without further revealing any algorithms that might be considered trade secrets, the manufacturer of the BIS monitor should be encouraged to release the device software in its original format to place BIS-related academic literature on a firm theoretical foundation and to promote further academic development of EEG monitoring algorithms.