Department of Emergency Medicine, University Medical Centre Groningen, Groningen, The Netherlands
Department of Emergency Medicine, Medical Centre Leeuwarden, Leeuwarden, The Netherlands.
BMJ Open. 2022 Sep 1;12(9):e059848. doi: 10.1136/bmjopen-2021-059848.
Previous studies show that prolonged exposure to a high inspired oxygen concentration (FiO) is associated with unfavourable haemodynamic effects. Until now, it is unknown if similar effects also occur after oxygen therapy of limited duration in the emergency department (ED).
To investigate the haemodynamic effects of a high FiO administered for a limited duration of time in patients who receive preoxygenation for procedural sedation and analgesia (PSA) in the ED.
DESIGN, SETTINGS AND PARTICIPANTS: In a prospective cohort study, cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were measured using the Clearsight non-invasive CO monitoring system in patients who received preoxygenation for PSA in the ED. Measurements were performed at baseline, after 5 min of preoxygenation via a non-rebreathing mask at 15 /L min and after 5 min of flush rate oxygen administration.
The primary outcome was defined as the change in CO (L/min) from baseline after subsequent preoxygenation with 15 L/min and flush rate.
Sixty patients were included. Mean CO at baseline was 6.5 (6.0-6.9) L/min and decreased to 6.3 (5.8-6.8) L/min after 5 min of oxygen administration at a rate of 15 L/min, and to 6.2 (5.7-6.70) L/min after another 5 min at flush rate (p=0.037). Mean SV remained relatively constant during this period, whereas mean SVR increased markedly (from 781 (649-1067), to 1244 (936-1695) to 1337 (988-1738) dyn/s/cm, p<0.001. Sixteen (27%) patients experienced a>10% decrease in CO.
Exposure of patients to a high FiO for 5-10 min results in a significant drop in CO in one out of four patients. Therefore, even in the ED and in prehospital care, where oxygen is administered for a limited amount of time, FiO should be titrated based on deficit whenever this is feasible and high flow oxygen should not be given as a routine treatment.
先前的研究表明，长时间暴露于高吸入氧浓度（FiO）与不利的血液动力学效应有关。到目前为止，尚不清楚在急诊科（ED）接受有限时间吸氧治疗后是否也会出现类似的效应。
研究在 ED 接受程序性镇静和镇痛（PSA）预吸氧的患者中，给予高 FiO 短时间治疗的血液动力学效应。
设计、地点和参与者：在一项前瞻性队列研究中，使用非侵入性 CO 监测系统 Clearsight 在 ED 接受 PSA 预吸氧的患者中测量心输出量（CO）、每搏量（SV）和全身血管阻力（SVR）。测量在基线时、通过非再呼吸面罩进行 5 分钟预吸氧时（15 L/min）以及进行 5 分钟冲洗速率吸氧后进行。
共纳入 60 例患者。基线时平均 CO 为 6.5（6.0-6.9）L/min，随后 5 分钟以 15 L/min 的速度给予氧气，CO 降至 6.3（5.8-6.8）L/min，再次 5 分钟以冲洗速率给予氧气，CO 降至 6.2（5.7-6.70）L/min（p=0.037）。在此期间，平均 SV 相对稳定，而平均 SVR 显著增加（从 781（649-1067）增至 1244（936-1695）至 1337（988-1738）dyn/s/cm，p<0.001）。16 例（27%）患者的 CO 下降>10%。
患者暴露于高 FiO 5-10 分钟，四分之一的患者 CO 显著下降。因此，即使在急诊科和院前护理中，氧气的给予时间有限，只要可行，FiO 应根据不足进行滴定，不应用高流量氧气作为常规治疗。
