Ecchymosis and/or haematoma formation after prophylactic administration of subcutaneous enoxaparin in the abdomen or arm of the critically ill patient.

INTRODUCTION: Ecchymosis and/or haematoma are the most common adverse events after subcutaneous administration of low molecular weight heparin. There is no strong recommendation as to the puncture site.

OBJECTIVE: To evaluate the adverse events, ecchymosis and/or haematoma after the administration of prophylactic subcutaneous enoxaparin in the abdomen vs the arm in the critically ill patient.

METHODOLOGY: A randomised, two-arm clinical trial (injection in the abdomen vs the arm), performed between July 2014 and January 2017, in an 18-bed, polyvalent intensive care unit. Patients receiving prophylactic enoxaparin, admitted >72h, with no liver or haematological disorders, a body mass index (BMI) >18.5, not pregnant, of legal age and with no skin lesions which would impede assessment were included. We excluded patients who died or who were transferred to another hospital before completing the evaluation. We gathered demographic and clinical variables, and the onset of ecchymosis and/or haematomas at the injection site after 12, 24, 48 and 72hours. A descriptive analysis was undertaken, with group comparison and logistic regression. The study was approved by the ethics committee with the signed consent of patients/families.

RESULTS: 301 cases (11 excluded): 149 were injected in the abdomen vs 141 in the arm. There were no significant differences in demographic and clinical variables, BMI, enoxaparin dose or antiplatelet administration [ecchymosis, abdomen vs arm, n(%): 66(44) vs 72(51), P=.25] [haematoma abdomen vs arm, n(%): 9(6) vs 14(10), P=.2]. Statistical significance was found in the size of the haematomas after 72h: [area of haematoma (mm2 ) abdomen vs arm, median (IQR): 2(1-5.25) vs 20(5.25-156), P=.027].

CONCLUSIONS: In our patient cohort, prophylactic subcutaneous enoxaparin administered in the abdomen causes fewer haematomas after 72hours, than when administered in the arm. The incidence rate of ecchymosis and haematoma was lower than the published incidence in critically ill patients, although patients receiving anti-platelet agents present a higher risk of injury. No relationship was observed in relation to BMI.