Cardiopulmonary Exercise Testing Before and After Intravenous Iron: a Prospective Clinical Study
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 26
- 试验地点
- 1
- 主要终点
- Change from baseline in oxygen consumption at anaerobic threshold (VO2AT) measured in mls/kg/min
研究概览
简要总结
Red blood cells contain a chemical called haemoglobin which carries oxygen from the lungs around the body. When the amount of haemoglobin is reduced, a patient is 'anaemic'. Anaemia can have many causes, but affects about a third of patients having major surgery in hospital. After their operation these anaemic patients are more likely to suffer serious complications. This may be because the body needs extra oxygen - and so enough haemoglobin - to heal and recover successfully from the trauma of surgery.
For a similar reason, patients' overall fitness before surgery is very important. Less fit patients are much more likely to get complications after surgery. To help us assess the risk of complications, the investigators measure patients' fitness before surgery using a cycling exercise test. The investigators monitor a number of things that show us how well the heart, the lungs and the muscles respond when they are under stress. People who are very anaemic tend to perform less well on this cycling test.
Anaemia is often due to a lack of iron, which helps make haemoglobin. Usually people get iron from foods such as red meat and spinach. Some conditions mean that patients lose iron, such as a tumour bleeding. Other illnesses make it difficult for the body to absorb iron from the gut in the first place. Both lead to a state of low iron in the body and eventually this leads to anaemia. One way to treat anaemia quickly before surgery is to give iron into the bloodstream (intra-venous). It is thought that this might reduce the risk of complications after surgery, but it is not known whether this is because it improves overall fitness, or for other reasons.
The investigators plan to carry out a study called CAPOEIRA-I (CArdio PulmOnary Exercise testing and IntRAvenous Iron) to find out whether giving patients intravenous iron improves their fitness. The investigators will measure this by doing a cycle exercise test before and then at least 10 days after the iron is given. The investigators will also measure how much the total amount of haemoglobin chnages with iron treatment. Intravenous iron is already routinely used for these patients, so the only additional activity for the study is the extra exercise test, some extra blood tests and the measurement of haemoglobin after the iron has taken effect.
详细描述
Anaemia is common in the elective surgical population, a prevalence of around 30% being consistently reported in large cohorts.
Cardiopulmonary exercise testing (CPET), which provides an objective assessment of aerobic fitness by measuring oxygen consumption (O2) and carbon dioxide production is widely considered the gold standard assessment of functional capacity as it dynamically tests the pulmonary, cardiovascular and musculoskeletal system and their interplay in a single test. CPET parameters are affected by a number of patient factors including effort, ability to turn the pedals on an exercise bike, pulmonary function, and crucially oxygen delivery to the respiring tissues, which is dependent on blood oxygen content and flow to the tissues via cardiac output.
The oxygen carrying capacity of arterial blood is largely influenced by the haemoglobin content (or total haemoglobin mass (tHb-mass)). tHb-mass affects CPET performance to a greater degree than haemoglobin concentration ([Hb]). [Hb] is dependent on plasma volume (PV) and shows a greater fluctuation day to day than tHb-mass.
Studies in athletes show the detrimental affect of blood volume loss (i.e. deliberate venesection) and haemoglobin content loss on CPET performance. The corollary of this is illegal blood manipulation, which improves CPET performance. The same is seen post altitude training camps with increased tHb-mass leading to improved maximal exercise performance.
Aerobic capacity is defined as the maximum amount of oxygen that can be consumed by the body per unit time and is the gold standard measure of physical fitness. VO2max is classically defined as 'a plateau in oxygen uptake attained during maximal exercise despite further increases in exercise workload, thereby defining the limits of the cardiorespiratory system'. However, many individuals do not reach a plateau in oxygen uptake despite maximum exertion, and the term VO2peak is used instead. This is the highest measured oxygen consumption during exercise and is typically averaged over a 30 second period. O2 at anaerobic threshold (VO2AT) is defined as: 'the highest sustained intensity of exercise for which the measurement of oxygen uptake can account for the entire energy requirement.' An alternative definition is 'the exercise intensity at which lactate starts to accumulate in the blood stream above rest'. These oxygen uptake variables are in part dependent on the oxygen carrying capacity of the blood, which is in turn dependent on blood haemoglobin levels.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 16 Years 至 110 Years（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Adult patients undergoing elective surgery
- •Having a CPET as part of routine care
- •Patients with a Hb value of < 130 g/L who are iron deficient, iron restricted/deplete or have functional iron deficiency as described in 5.2 and Appendix 1
- •Able to provide written informed consent.
- •Patients with mixed aetiology anaemia who are either iron deficient, iron replete or functionally iron deficient alongside B12 or folate deficiency will be eligible for the study alongside treatment of their other nutritional deficiency.
排除标准
- •Pregnant women
- •Hypersensitivity to the active substance, to 'Monofer' (iron isomaltoside 1000) or any of its excipients
- •Known documented serious hypersensitivity to any parenteral iron products
- •Haemochromatosis or other iron overload states
- •Acute liver or renal failure
- •Active infection
- •Those receiving a blood transfusion between the CPET tests
- •Unable/ contraindication to perform CPET (Appendix 3)
- •Haemoglobinopathies such as Sickle Cell Anaemia or Thalassemia
- •Other cause for anaemia such as haematological malignancy, haemolysis, hypothyroidism.
研究组 & 干预措施
Major surgery
- Adult patients undergoing elective surgery
- Having a CPET as part of routine care
- Patients with a Hb value of < 130 g/L who are iron deficient, iron restricted/deplete or have functional iron deficiency.
- Able to provide written informed consent.
干预措施: MonoFer (Drug)
结局指标
主要结局
Change from baseline in oxygen consumption at anaerobic threshold (VO2AT) measured in mls/kg/min
时间窗: Up to 6 weeks
Using cardiopulmonary exercise testing (CPET) to assess the oxygen consumption at anaerobic threshold before and then after intravenous iron therapy.
次要结局
- Change from baseline haemoglobin concentration [Hb] measured in grams per litre (g.l-1)(Up to 6 weeks)
- Change from baseline in peak oxygen consumption (VO2peak) measured in mls/kg/min(Up to 6 weeks)
- Change from baseline in total haemoglobin mass measured in grams(Up to 6 weeks)
- Change form baseline in hepcidin assay measured in nanograms per millilitre (ng/ml)(Up to 6 weeks)
- Change form baseline in serum ferritin measured in micrograms per litre(Up to 6 weeks)
- Change form baseline in transferrin saturation (TSAT) (percentage)(Up to 6 weeks)
- Change form baseline in serum iron measured in micromols per litre(Up to 6 weeks)
- Length of hospital stay in days(Up to 6 weeks)