Discharge haematocrit as clinical indicator for blood transfusion audit in surgery patients

SUMMARY. Three cohorts of elective surgical patients were reviewed in order to develop a method in which the discharge haematocrit can serve as a clinical indicator for a subsequent study of the use of blood transfusion therapy. Three different levels of discharge haematocrit were evaluated: 36, 33, and 30% for ‘generous’, ‘intermediate’, and ‘strict’ criteria, respectively. Discharge haematocrits (%, mean ± SD) for patients not transfused were 29.6±4.6, 33.7 ± 5.0, and 33.6 ± 3.4 for three different surgical groups (cardiac, orthopaedic, and urological surgical patients). When discharge haematocrits greater than 33% (‘intermediate’) were considered excessive due to previous transfusion, the prevalence of patients identified was 9, 6.5 and 13%, respectively. We found no relationship between the length of stay in hospital and the number of blood units transfused or patient discharge haematocrit levels. When the length of stay of patients identified by exceeding the clinical indicator was compared to that of patients not identified, orthopaedic and urological surgical patients showed no difference; however, cardiac surgical patients who exceeded the clinical indicator had shorter hospital stays compared to patients who were not so identified. We conclude the following: 1 The discharge haematocrit can be used as a clinical indicator for a subsequent review of use in order to evaluate the appropriateness of blood transfusion therapy. 2 The prevalence of patients identified who exceeded the clinical indicator, among three elective surgical patient groups, suggests that this indicator is applicable across elective surgical categories in order to target transfusion medicine education programmes and clinical outcome studies. 3 Additional factors important to the ‘transfusion trigger’, such as blood lost during hospitalization, may need to be included with the discharge haematocrit as clinical indicators in order to evaluate blood transfusion therapy in this setting.