Although anaemia is normally diagnosed and treated by doctors, I thought it would be worth writing a blog for my patients about anaemia because although the management is becoming clearer, many of my patients are confused by different information provided by different doctors approaching the problem from different directions.
First a little about the numbers! We have recently moved the decimal point to the right so that a haemoglobin (‘blood count’) of 13 is now 130 grams per litre. Our American colleagues are little behind us!! So please be careful about the decimal point
Anaemia is relatively common especially in patients with gynaecological problems, pregnancy or cancer, but many more patients see their doctor because they feel rundown tired. Many of these patients will have blood tests showing a relatively low level of iron but a normal haemoglobin. The numbers may not be the cause of the symptoms. There is little evidence about treating the iron in the absence of anaemia although many doctors do so. This must not be confused with anaemia due to iron deficiency which may be due to diet or the uptake of iron in the body or chronic inflammation. These patients do see a significant improvement if given iron tablets.
Many operations do not involve significant blood loss so we do not routinely test patients for anaemia before anaesthesia. Indeed, slightly lower than normal haemoglobin levels may be beneficial during the perioperative period in terms of delivering oxygen around the body and reducing the risk of clots. The operation can go ahead safely.
However, for operations where blood loss is expected to exceed 500 mls we take a totally different approach. We know that the risk of complications is significantly increased if patients undergo these operations when their haemoglobin is low. They need more blood and blood products and have a longer hospital stay. A recent article in the journal Anaesthesia has set down guidelines for these operations (Anaesthesia, 2019, 74 (suppl 1) 49-74). These patients should have their haemoglobin checked well before surgery and we should treat anyone with a haemoglobin below 130. Before treatment further blood tests are undertaken to check for chronic inflammation, kidney disease and vitamin deficiency which may need specific treatment or referral to other specialists. Normally, surgery is postponed and six weeks of oral iron should correct the problem. The haemoglobin should be checked after four weeks and if the patient is still anaemic or if the surgery cannot wait for six weeks we would give intravenous iron which has had a bad reputation but is now known to be relatively safe although it does need to be given in an acute hospital setting because of the small risk of allergic reactions.