Objective:To compare the safety apnea time during endotracheal intubation in the patients from different altitudes using oxygen reserve index (ORI).Methods:Sixty American Society of Anesthesiologists physical status Ⅰor Ⅱ patients, aged 18-70 yr, undergoing elective surgery requiring tracheal intubation under general anesthesia and requiring catheterization via arterial puncture, were included.Among the patients, 30 cases who had long lived at an altitude of 1 500-3 000 m in Qinghai Province People′s Hospital (Xining, 2 200 m above sea level) served as middle-altitude group, and 30 Tibetan patients who had long lived at an altitude >3 000-meter area in Yushu People′s Hospital (Yushu, 3 600 m above sea level) served as high-altitude group.The patients were preoxygenated for 5 min before induction of anesthesia, and then endotracheal intubation was performed with a video laryngoscope.Before induction (T 0), at 3 min of pre-oxygenation (T 1), and at 5 min of pre-oxygenation (T 2), arterial blood was collected for blood gas analysis, and PaO 2 was recorded, ORI and SpO 2 were simultaneously recorded.The time from the beginning of intubation to the time when ORI was decreased to 0 and the time from the beginning of intubation to the time when SpO 2 was decreased to 98% were recorded. Results:Compared with middle-altitude group, the time from the beginning of intubation to the time when ORI was decreased to 0 and the time from the beginning of intubation to the time when SpO 2 was decreased to 98% were significantly prolonged ( P<0.05), and no significant change was found in SpO 2, ORI and PaO 2 at each time point in high-altitude group ( P>0.05). Conclusions:The safety apnea time during endotracheal intubation is longer in the patients at high altitudes (altitude > 3000 m) than those at the moderate altitudes (altitude 1500-3000 m).

BACKGROUND:Among the surface modification technologies of metal implants,micro-arc oxidation has been widely concerned for its convenience,low cost and ability to effectively adjust the microstructure and elements of surface coatings. OBJECTIVE:To summarize research advances in physical and chemical properties and biological activities of oxidation coatings prepared by micro-arc oxidation on different materials. METHODS:The articles about the effects of micro-arc oxidation on the biological activity of medical metals were searched in PubMed and Web of Science based on the English search terms"MAO,micro-arc oxidation,osseointegration,mechanical property,biological activity,angiogenesis,fibrogenesis".The search time was from January 2016 to December 2022.According to the inclusion and exclusion criteria,82 articles were finally retained for review. RESULTS AND CONCLUSION:Micro-arc oxidation is a potential surface modification technology,which can greatly improve the success rate of implantation,and can be widely used in other fields.The specific reasons are as follows:(1)Micro-arc oxidation technology forms special porous morphology on the surface of materials,which can optimize the mechanical properties such as wear resistance and corrosion resistance,contributing to the reduction of the degradation rate of magnesium alloys.(2)Micro-arc oxidation technology can significantly enhance the bioactivity and improve the bioinertness of titanium and titanium alloys through the addition of strontium,hydroxyapatite and other metallic or nonmetallic substances to its porous morphology for helping elevate its osteogenic differentiation,angiogenesis,fibrogenesis and other biological activities.

BACKGROUND:Micro-arc oxidation can effectively add bioactive elements to the metal surface and improve the anti-bacterial and anti-inflammatory properties of biomedical metal materials,so this technology has become one of the hotspots of biomedical materials. OBJECTIVE:To summarize the anti-bacterial and anti-inflammatory properties of surface coatings prepared by the combination of micro-arc oxidation and other surface modification technologies. METHODS:Articles from January 1996 to December 2022 were searched on CNKI,WanFang and PubMed databases using Chinese and English search terms"micro-arc oxidation,antibacterial properties,anti-inflammatory properties,metal implants".After preliminary screening according to inclusion and exclusion criteria,89 articles were retained and summarized. RESULTS AND CONCLUSION:The ceramic layer prepared by micro-arc oxidation can improve the anti-bacterial and anti-inflammatory properties of titanium,magnesium and other alloys.Combination with other surface modification technologies can effectively solve the effect of pores on the surface properties of the alloy,and further improve the biological properties of the oxide film.It has a wide application prospect in orthopedics and dentistry.At present,most studies are limited to metal coatings,and most of them focus on metal elements with good antibacterial properties such as silver and copper,while only a few studies mention non-metallic coatings such as graphene oxide,hydroxyapatite and chitosan.In the future,extensive studies can be conducted on inorganic coatings and polymer coatings,and more combinations of different bioactive elements can also be adopted to improve antibacterial properties.Currently,studies on the inflammation of implant coatings prepared by micro-arc oxidation are mostly limited to the immune system and focused on macrophages,while studies on neutrophils and platelets are scarce.In the future,a variety of advanced technologies should be combined to explore the specific effects of micro-arc oxidation coating on other immune cells and inflammatory cells.