Morkane Clare M, McKenna Helen, Cumpstey Andrew F, Oldman Alex H, Grocott Michael P W, Martin Daniel S
1Division of Surgery and Interventional Science (University College London) and Royal Free Perioperative Research Group, Department of Anaesthesia, Royal Free Hospital, 3rd Floor, Pond Street, London, NW3 2QG UK.
University of Southampton/University Hospital Southampton and NIHR Biomedical Research Centre, Tremona Rd, Southampton, SO16 6YD UK.
Perioper Med (Lond). 2018 Jul 24;7:17. doi: 10.1186/s13741-018-0098-3. eCollection 2018.
Considerable controversy remains about how much oxygen patients should receive during surgery. The 2016 World Health Organization (WHO) guidelines recommend that intubated patients receive a fractional inspired oxygen concentration (FIO) of 0.8 throughout abdominal surgery to reduce the risk of surgical site infection. However, this recommendation has been widely criticised by anaesthetists and evidence from other clinical contexts has suggested that giving a high concentration of oxygen might worsen patient outcomes. This retrospective multi-centre observational study aimed to ascertain intraoperative oxygen administration practice by anaesthetists across parts of the UK.
Patients undergoing general anaesthesia with an arterial catheter in situ across hospitals affiliated with two anaesthetic trainee audit networks (PLAN, SPARC) were eligible for inclusion unless undergoing cardiopulmonary bypass. Demographic and intraoperative oxygenation data, haemoglobin saturation and positive end-expiratory pressure were retrieved from anaesthetic charts and arterial blood gases (ABGs) over five consecutive weekdays in April and May 2017.
Three hundred seventy-eight patients from 29 hospitals were included. Median age was 66 years, 205 (54.2%) were male and median ASA grade was 3. One hundred eight (28.6%) were emergency cases. An anticipated difficult airway or raised BMI was documented preoperatively in 31 (8.2%) and 45 (11.9%) respectively. Respiratory or cardiac comorbidity was documented in 103 (27%) and 83 (22%) respectively. SpO < 96% was documented in 83 (22%) patients, with 7 (1.9%) patients desaturating < 88% at any point intraoperatively. The intraoperative FIO ranged from 0.25 to 1.0, and median PaO/FIO ratios for the first four arterial blood gases taken in each case were 24.6/0.5, 23.4/0.49, 25.7/0.46 and 25.4/0.47 respectively.
Intraoperative oxygenation currently varies widely. An intraoperative FIO of 0.5 currently represents standard intraoperative practice in the UK, with surgical patients often experiencing moderate levels of hyperoxaemia. This differs from both WHO's recommendation of using an FIO of 0.8 intraoperatively, and also, the value most previous interventional oxygen therapy trials have used to represent standard care (typically FIO = 0.3). These findings should be used to aid the design of future intraoperative oxygen studies.
关于手术期间患者应接受多少氧气仍存在很大争议。2016年世界卫生组织（WHO）指南建议，在整个腹部手术过程中，插管患者应接受吸入氧分数（FIO）为0.8的氧气，以降低手术部位感染的风险。然而，这一建议受到了麻醉师的广泛批评，并且来自其他临床背景的证据表明，给予高浓度氧气可能会使患者的预后恶化。这项回顾性多中心观察性研究旨在确定英国部分地区麻醉师的术中氧气给药实践。
在两个麻醉实习生审计网络（PLAN、SPARC）所属医院接受全身麻醉且留置动脉导管的患者符合纳入标准，除非正在进行体外循环。从2017年4月和5月连续五个工作日的麻醉记录和动脉血气（ABG）中获取人口统计学和术中氧合数据、血红蛋白饱和度和呼气末正压。
纳入了来自29家医院的378例患者。中位年龄为66岁，205例（54.2%）为男性，中位ASA分级为3级。108例（28.6%）为急诊病例。术前记录有预期困难气道或BMI升高的分别为31例（8.2%）和45例（11.9%）。分别有103例（27%）和83例（22%）记录有呼吸或心脏合并症。83例（22%）患者记录有SpO< 96%，7例（1.9%）患者在术中任何时候饱和度< 88%。术中FIO范围为0.25至1.0，每个病例采集的前四份动脉血气的中位PaO/FIO比值分别为24.6/0.5、23.4/0.49、25.7/0.46和25.4/0.47。
目前术中氧合差异很大。目前，术中FIO为0.5代表了英国的标准术中实践，手术患者经常出现中度高氧血症。这与WHO术中使用FIO为0.8的建议不同，也与之前大多数介入性氧疗试验用于代表标准治疗的值（通常FIO = 0.3）不同。这些发现应用于帮助设计未来的术中氧研究。
