Objective: To evaluate the safety of preoxygenation with high-flow nasal oxygenation in elderly patients during induction of general anesthesia with endotracheal intubation.
Methods: Fifty-six elderly patients without difficult airway were randomized equally into high-flow nasal oxygen group (HF group) and conventional mask oxygen group (M group). Preoxygenation was performed for 5 min before induction of general anesthesia and endotracheal intubation. Oxygenation was maintained during laryngoscopy in HF group, and ventilation lasted until laryngoscopy in M group. For all the patients, the general data, cross-sectional area (CSA) of the gastric antrum measured by ultrasonography, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2) and arterial oxygen saturation (cSO2) were recorded before preoxygenation (T1), at 5 min of preoxygenation (T2) and immediately after intubation (T3). The safety time of asphyxia, intubation time, times of mask ventilation and postoperative complications were compared between the two groups.
Results: The general data were comparable between the two groups. After 5 min of preoxygenation, PaO2 and cSO2 were significantly increased in both groups, and PaO2 was significantly higher in HF group than in M group (F=118.108 vs 9.511, P < 0.05). Both PaO2 and cSO2 decreased after intubation, but PaO2 decreased more slowly in HF group and still remained higher than that at T1; cSO2 decreased significantly in M group to a lower level than that at T1. Compared with those in M group, the patients in HF group showed a significantly longer safety time of asphyxia (t=5.305, P < 0.05) with fewer times of mask ventilation (χ2= 6.720, P < 0.05). PaCO2 increased after intubation in both groups but was comparable between the two groups (F=3.138, P > 0.05).
Conclusion: High-flow nasal oxygen is safe, simple and effective for pre-oxygenation, which, as compared with the conventional oxygen mask, improves arterial oxygen partial pressure and prolongs the safety time of asphyxia to ensure the safety of airway management during induction of general anesthesia in elderly patients with endotracheal intubation.
目的: 评估经鼻高流量预充氧在老年患者全麻气管插管诱导期的安全性研究。
方法: 56例非困难气道老年患者，采用随机数字表法分为经鼻高流量吸氧组（HF组）和传统面罩经口鼻吸氧组（M组），28例/组。全麻气管插管诱导给药前预充氧5 min，HF组喉镜检查期间维持给氧，M组通气持续到喉镜检查。观察并记录两组患者基本资料，预充氧前（T1）、预充氧5 min（T2）及插管成功即刻（T3）的超声下胃窦横截面积（CSA）和动脉血气分析指标：PaO2、PaCO2、cSO2，窒息安全时间，插管时间，面罩通气的次数及术后并发症。
结果: 两组患者的基本资料差异无统计学意义。预充氧5 min，两组患者的PaO2和cSO2均明显升高，且HF组PaO2较M组明显（F=118.108vs 9.511，P < 0.05），插管成功后PaO2和cSO2均下降，HF组的PaO2值较M组下降缓慢，且仍高于其T1时点，而M组的cSO2值下降显著，低于其T1时点值。HF组窒息安全时间显著高于M组（t=5.305，P < 0.05），且HF组面罩通气次数少于M组（χ2=6.720，P < 0.05）。两组插管后的PaCO2值均增高，但两组比较差异无统计学意义（F=3.138，P > 0.05），其余结果差异也无统计学意义（P > 0.05）。
结论: 经鼻高流量吸氧是一种安全简单有效的预充氧方式，与传统的面罩预充氧相比，能提高老年患者的动脉氧分压，延长患者窒息安全时间，可保障老年患者全麻诱导插管时气道管理的安全。
Keywords: airway management; gastric antrum cross-sectional area; high-flow nasal oxygenation; safety time of asphyxia.