Relationship of Oxygenation During Anaesthesia in the Presence of N2O or N2 to Mode of Ventilation
试验速览
- 阶段
- 4 期
- 状态
- 已完成
- 入组人数
- 20
- 主要终点
- PaO2
研究概览
简要总结
Nitrous oxide is a standard part of most anaesthetic breathing mixtures. It has often been assumed that it reduces the amount of oxygen reaching the lower parts of the lung. However the results of previous studies and of some computer modelling suggests the opposite may be true, and that oxygen levels in the blood are actually higher with nitrous oxide. This study seeks to determine whether nitrous oxide increases or decreases blood oxygen levels in anaesthetized patients.
详细描述
The concentrating and second gas effects of nitrous oxide (N2O) uptake have been well described, and are produced by rapid uptake of N2O during the first several minutes of an inhalational anesthetic. This significantly increases alveolar and arterial O2 partial pressure. Theoretical modelling of alveolar gas exchange has predicted that these effects may not be transient but may be a persisting phenomenon. However, N2O is known to promote absorption atelectasis in poorly ventilated lung units.
This study, carried out pre-cardiopulmonary bypass in 20 patients undergoing coronary artery surgery, measures change in PaO2 after a minimum of 30 minutes of relaxant general anesthesia with a FIO2 of 30%. Patients are randomised to two groups. The intervention group has N2O introduced following baseline blood gas measurements, while the control group continued breathing an identical FIO2 in N2. The change in PaO2 in the two groups is the primary endpoint for comparison.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Patients undergoing elective coronary artery bypass surgery
排除标准
- •Age under 18 years, emergency surgery
研究组 & 干预措施
Nitrous oxide
Nitrous oxide 70% as balance gas in inspired mixture
干预措施: Nitrous oxide (Drug)
Nitrogen
Nitrogen instead of nitrous oxide 70% as balance gas in inspired mixture
干预措施: Nitrous oxide (Drug)
结局指标
主要结局
PaO2
时间窗: Minimum of 30 minutes after induction of anaesthesia
Measured change in PaO2 after a minimum of 30 minutes of general anaesthesia, following sternotomy, in the two groups.
次要结局
- Change in pulmonary deadspace and shunt fractions(Minimum of 30 minutes after induction of anaesthesia)