[Preoperative blood ordering in elective colon surgery: requirement or routine?]

Preoperative blood ordering is frequently in elective colon surgery, even for procedures that rarely require blood transfusion. Most often this procedure is performed without proper analysis of the real needs. The aim of this study was to evaluate the patients who receive transfusion and determining their associated factors.

Retrospective study of all consecutive patients scheduled for elective colon surgery was carried out at 2007-2012. Several clinico-pathological and surgical variables were analyzed and predictive blood transfusion indices such as the cross-matched/transfusion ratio (C/T ratio), transfusion index and transfusion probability were calculated. Patients were divided in 2 groups according have received perioperative surgical transfusion or not.

There were 457 surgery patients. A total of 171 blood units, in a 74 patients were perioperative transfused. Overall cross-matched transfused ratio was 5.34, the transfusion probability 162%, and the transfusion index 0.18. Variables that were significantly associated with receiving blood transfusion in a multivariable analysis were a preoperative haemoglobin level less than 10 g/dl (OR: 309.8; 95% CI: 52.7-985.2), chronic pulmonary obstructive disease (OR: 3.7; 95% CI: 1.3-10.7), oral anticoagulant therapy (OR: 5.7; 95% CI: 1.7-19.4) and surgical time over 120 min (OR: 10.7; 95% CI: 4.7-24.1).

Likelihood of receiving perioperative transfusion in elective colon surgery is very low. Among their associated factors, the haemoglobin level less than 10 g/dl is the one with strongest association. Those patients with such low preoperative haemoglobin level should not be scheduled for elective colon surgery until they received specific treatment.