Abstract：
BACKGROUND: Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia.
METHODS: We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.
RESULTS: We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.
CONCLUSIONS: Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.
UNASSIGNED: PROSPERO CRD42022326046.
METHODS: We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.
RESULTS: We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.
CONCLUSIONS: Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.
UNASSIGNED: PROSPERO CRD42022326046.
摘要：
背景：普遍推荐在全身麻醉诱导前进行预氧合，以延长安全的呼吸暂停时间。预充氧的最佳技术尚不清楚。我们进行了系统评价，以确定与全身麻醉的成年患者的最大有效性相关的预氧合技术。
方法：我们搜索了6个数据库，用于研究年龄≥16岁的患者的随机对照试验。在任何环境下接受全身麻醉，并比较不同的预氧合技术和方法。我们的主要有效性结果是安全的呼吸暂停时间，次要结局包括动脉血氧饱和度降低的发生率;气道管理期间的最低SpO2;达到潮气末氧气浓度90%的时间;以及预氧结束时的[公式:见正文]和[公式:见正文].我们根据建议的分级评估了证据的质量，评估,发展和评价（等级）建议。
结果：我们纳入了3914例患者的52项研究。与其他策略相比，头戴位置的患者的高流量鼻氧最可能与延长的安全呼吸暂停时间有关，与仰卧和抬头位置的面罩预充氧相比，平均差异（95％可信间隔）为291（138-456）s和203（79-343）s，分别。对没有呼吸氧合的研究的亚组分析也显示，在抬头位置的高流量鼻氧是排名最高的技术，与仰卧和抬头位置的面罩相比，安全呼吸暂停时间在统计学上显着延迟（95％可信间隔），分别为222（63-378）s和139（15-262）s，分别。高流量鼻氧也是在预氧合结束时增加[公式：见正文]的最高排名技术。然而,与其他技术相比，当使用带压力支持的面罩时，动脉饱和度降低的可能性较小。当患者仰卧位深呼吸时，[公式：见正文]最有可能是最低的。
结论：与单纯使用面罩相比，在全身麻醉诱导前使用高流量鼻吸氧时，成人在安全呼吸暂停时间方面最有效。此外，在接受评估的患者中，抬头位置的高流量鼻氧可能是延长安全呼吸暂停时间的最有效技术。临床医生应在常规实践中考虑此技术和患者位置。
■PROSPEROCRD42022326046。
方法：我们搜索了6个数据库，用于研究年龄≥16岁的患者的随机对照试验。在任何环境下接受全身麻醉，并比较不同的预氧合技术和方法。我们的主要有效性结果是安全的呼吸暂停时间，次要结局包括动脉血氧饱和度降低的发生率;气道管理期间的最低SpO2;达到潮气末氧气浓度90%的时间;以及预氧结束时的[公式:见正文]和[公式:见正文].我们根据建议的分级评估了证据的质量，评估,发展和评价（等级）建议。
结果：我们纳入了3914例患者的52项研究。与其他策略相比，头戴位置的患者的高流量鼻氧最可能与延长的安全呼吸暂停时间有关，与仰卧和抬头位置的面罩预充氧相比，平均差异（95％可信间隔）为291（138-456）s和203（79-343）s，分别。对没有呼吸氧合的研究的亚组分析也显示，在抬头位置的高流量鼻氧是排名最高的技术，与仰卧和抬头位置的面罩相比，安全呼吸暂停时间在统计学上显着延迟（95％可信间隔），分别为222（63-378）s和139（15-262）s，分别。高流量鼻氧也是在预氧合结束时增加[公式：见正文]的最高排名技术。然而,与其他技术相比，当使用带压力支持的面罩时，动脉饱和度降低的可能性较小。当患者仰卧位深呼吸时，[公式：见正文]最有可能是最低的。
结论：与单纯使用面罩相比，在全身麻醉诱导前使用高流量鼻吸氧时，成人在安全呼吸暂停时间方面最有效。此外，在接受评估的患者中，抬头位置的高流量鼻氧可能是延长安全呼吸暂停时间的最有效技术。临床医生应在常规实践中考虑此技术和患者位置。
■PROSPEROCRD42022326046。
