ICU Management & Practice, Volume 21 - Issue 6, 2021
Anaemia is defined by haemoglobin (Hb) < 12 g/dL for women and Hb below 13 g/dL for men, according to the WHO (1968). Anaemia is a prevalent condition that affects nearly all critically ill patients. Approximately two-thirds of patients are anaemic at admission in Intensive Care Units (ICU) (Vincent et al. 2002); nearly 100% of the remainder become anaemic during their ICU stay (Napolitano et al. 2017), 77% of patients are still anaemic at hospital discharge (Walsh et al. 2006), and many persist to be anaemic for several months after leaving the hospital. Warner et al. (2020) showed that the prevalence of anaemia post hospitalisation was 56% at 3 months, 52% at 6 months, and 45% at 12 months among those alive and with available haemoglobin (Hb) measurements. In addition, there is scientific evidence that lower mean Hb levels are associated with higher SOFA scores, a longer length of stay, and higher mortality rates (Vincent et al. 2002). Anaemia becomes an issue when it is linked with insufficient oxygen supply to vital organs.
The cause of anaemia in critical illness is complex and multifactorial and has been a topic of debate in critical care medicine for many years. Primary mechanisms of anaemia may include haemodilution, blood loss, increased hepcidin levels, reduced erythropoietin levels, neocytolysis, drug reactions, and nutrient deficiency (Astin and Puthucheary 2014).
Haemodilution
Blood Loss
Hepcidin
Reduced Levels of Erythropoietin
Neocytolysis
Nutrient Deficiency
Drug Reactions
Conclusion
Conflict of Interest
None.
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