The goal of his study was to show that oxygen saturation measurement in the distal part of injured upper extremity is one of the best method to assess post-traumatic blood flow disturbances and the necessity for exploration of brachial artery in supracondylar fractures. 32 children, age 4-16, with Gartland's displaced extension type III injuries and distal disruption of blood flow were treated between 2014 and 2018. Blood disturbances were measured by pulse oximeter. Very good or good results were achieved in 22 non-operatively treated patients where pulseless pink hand symptoms occurred and, after reduction, disappeared. Very good or good results were achieved in 9 patients with pulseless pale and cold hand symptoms. In one patient with pulseless hand (verified by pulse oximeter) but without symptoms of cold hand we decided to explore brachial artery after angio CT examination (Angio-CT showed complete entrapment of the brachial artery). In conclusion we think that oxygen saturation measurement in dislocated supracondylar fractures in children is the best method. It allows us determine whether to avoid or to perform exploration of brachial artery. It is also easily accessible in comparison to the Doppler US or other imaging tools.