不同吸氧流量对高海拔高原地区病人术后血氧饱和度的影响

目的 :探讨高海拔高原(海拔>4 000 m)地区全身麻醉手术病人,不同吸氧流量对于术后血氧饱和度(saturation of peripheral oxygen, SpO_2)的影响。方法:选取西藏阿里地区人民医院2017年8月至2018年4月在气管插管全身麻醉下手术的80例病人。采用随机数字表法,分为4组:拔管后2 L/min吸氧为L1组,4L/min吸氧为L2组,6L/min吸氧为L3组,8L/min吸氧为L4组,每组各20例。分别记录进入手术室后未吸氧时(T0)的SpO_2,以及苏醒拔管后,给予口鼻面罩吸氧30min、1h、2h、4h、24h时的SpO_2。结果:本研究男47例,女33例,年龄19～58岁,体重48～72 kg,术前评估病人为美国麻醉医师学会Ⅰ、Ⅱ级。所有病人术后拔管给予面罩吸氧,SpO_2较术前均有升高(P<0.05)。吸氧流量为2L/min时,SpO_2处于较低水平。吸氧流量为4L/min时,SpO_2已接近低海拔地区健康人群正常值。吸氧流量≥6 L/min时,SpO_2不再随吸氧流量的增加而升高。吸氧4h后,L_3、L_4组与L_2组比较,SpO_2差异无统计学意义(P>0.05),吸氧流量可降低至4L/min。继续吸氧至术后24h,L1组SpO_2为94.86%,接近富氧环境的95%。因此,吸氧流量24h后可降为2L/min。结论:高海拔高原地区全身麻醉病人术后早期吸氧流量建议≥6L/min。此后可以降至4L/min和2L/min,避免高流量氧的浪费和氧中毒风险。

Ataxia,acute mountain sickness,and high altitude cerebral edema

Previous investigations suggest that ataxia is common and often one of the most reliable warning signs of high altitude cerebral edema(HACE). The aim of this study was to investigate the diagnostic role of ataxia in acute mountain sickness(AMS)and HACE among mountain rescuers on the quake areas,and in approaching the relation between AMS and HACE. After the earthquake on April 14,2010,approximately 24 080 lowland rescuers were rapidly transported from sea level or lowlands to the mountainous rescue sites at 3 750 ~ 4 568 m,and extremely hardly worked for an emergency treatment after arrival. Assessments of acute altitude illness on the quake areas were using the Lake Louise Scoring System. 73 % of the rescuers were found to be developed AMS. The incidence of high altitude pulmonary edema(HAPE)and HACE was 0.73 % and 0.26 %,respectively,on the second to third day at altitude. Ataxia sign was measured by simple tests of coordination including a modified Romberg test. The clinical features of 62 patients with HACE were analyzed. It was found that the most frequent,serious neurological symptoms and signs were altered mental status(50/62,80.6 %)and truncal ataxia(47/62,75.8 %). Mental status change was rated slightly higher than ataxia,but ataxia occurred earlier than mental status change and other symptoms. The earliest sign of ataxia was a vague unsteadiness of gait,which may be present alone in association with or without AMS. Advanced ataxia was correlated with the AMS scores,but mild ataxia did not correlate with AMS scores at altitudes of 3 750~4 568 m. Of them,14 patients were further examined by computerized tomographic scanning of the brain and cerebral magnetic resonance imagines were examined in another 15 cases. These imaging studies indicated that the presence of the cerebral edema was in 97 % of cases who were clinically diagnosed as HACE(28/29). Ataxia seems to be a reliable sign of advanced AMS or HACE,so does altered mental status.

A necklace of pearl in high altitude medicine and hypoxic physiology in Yushu Earthquake

During Yushu Earthquake,a large number of rescuers flocked to the mountainous quake areas. Under such a very specific circumstance,a high incidence of acute altitude illness was observed in rescuers who rapidly traveled from near sea level to an altitude of 4 000 m. It is evident that acute altitude illness leads to a significant human and economic toll,and also seriously influences the mountain rescue operation. So what does this teach us about mountain rescue in Yushu? Professor Wu Tianyi and many other authors collected shining points of the experiences and drew the lessons from the Yushu Earthquake into this special issue in Engineering Sciences which is like to thread pearl beads for a necklace. What readers learn from this special issue will have implications for the health and well-being of all high altitude populations all over the world.

Organochlorine Pesticides(OCPs) in Soils Along the Eastern Slope of the Tibetan Plateau

Soil samples collected from several sites along an altitudinal transect on the eastern slope of the Tibetan Plateau were analyzed for hexachlorobenzenes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs).The results showed that HCHs and DDTs were found in the soil samples from the remote high altitude areas away from source regions,which confirmed the long-range atmospheric transport phenomenon of these organochlorine pesticides(OCPs) insecticides.The OCP concentrations in the soils had a significant negative correlation with altitude;they showed a trend to increase with decreasing altitude,but the increase was not continuous,being interrupted at some moderate-altitude sites on the transect.The distances from the source region,landforms,soil properties,and physical-chemical properties of OCPs were more important than total organic carbon content to the distribution of OCPs in soils disturbed by human activities.An analysis of the compositions of HCH isomers and DDTs revealed predominantly low ratios of α-HCH to γ-HCH,ranging from 0.06 to 4.79,which suggested current lindane inputs.On the other hand,low p,p-DDT/p,p-DDE and o,p-DDT/p,p-DDT ratios were observed,indicating mainly aged historical DDT residues in the study area.