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, SpO₂）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,4 L/min吸氧为L₂组,6 L/min吸氧为L₃组,8 L/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SpO₂ ,以及苏醒拔管后,给予口鼻面罩吸氧30 min、1 h、2 h、4 h、24 h时的SpO₂。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,SpO₂较术前均有升高（P<0.05）。吸氧流量为2 L/min时,SpO₂处于较低水平。吸氧流量为4 L/min时,SpO₂已接近低海拔地区健康人群正常值。吸氧流量≥6 L/min时,SpO₂不再随吸氧流量的增加而升高。吸氧4 h后,L₃、L₄组与L₂组比较,SpO₂差异无统计学意义（P>0.05）,吸氧流量可降低至4 L/min。继续吸氧至术后24 h,L₁组SpO₂为94.86%,接近富氧环境的95%。因此,吸氧流量24 h后可降为2 L/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≥6 L/min。此后可以降至4 L/min和2 L/min,避免高流量氧的浪费和氧中毒风险。

Objective To study the effect of oxygen therapy by different flow on pulse arterial oxygen saturation (SpO₂) of postoperative patients of general anesthesia in high altitude area. Methods Eighty cases with operation under general endotracheal anesthesia were enrolled in the study between August 2017 and April 2018 in Ali district People's Hospital of Tibet. By random number table, the patients were divided into 4 groups according to oxygen flow after extubation including 2 L/min (group L₁), 4 L/min (group L₂), 6 L/min (group L₃) and 8 L/min (group L₄). SpO₂ was recorded as baseline before operation without oxygen inhalation and 30 min, 1 h, 2 h, 4 h or 24 h later after oxygen inhalation with oral and nasal mask ventilation. Results There were 47 male and 33 female cases with age range 19-58 years and weight 48-72 kg. The level of American Association of Anesthesiologists was grade Ⅰ-Ⅱ preoperatively. All the SpO₂ of cases was higher by oxygen therapy with oral and nasal mask after extubation of general anesthesia than before surgery (P< 0.05). SpO₂ remained lower level at oxygen flow 2 L/min and was close to healthy people in low altitude areas at 4 L/min. However, SpO₂ increased no longer when oxygen flow increased to 6 L/min or more. There was no significant difference in oxygen saturation between group L₂ and group L₃ and between group L₂ and group L₄ (P> 0.05) after 4 hours of intake oxygen. Therefore oxygen flow could be reduced to 4 L/min. When patients intaked oxygen for 24 h after surgery, SpO₂ in group L₁ was 94.86% which is close to 95% the SpO₂ of healthy people. We recommended that oxygen flow could be reduced to 2 L/min 24 h later. Conclusions Early oxygen intake in patients with general anesthesia in high altitude areas need 6 L/min of oxygen flow or more. Thereafter, it can be reduced to 4 L/min and 2 L/min for avoiding the waste of high flow oxygen and the risk of oxygen poisoning.