A method for percutaneously inserting an improved pediatric intra-aortic balloon. The improvement comprises a soft tip having a self occluding lumen capable of accommodating a guide wire. A removable pull tube is disposed within the self occluding lumen to prevent occlusion of the self occluding lumen. The catheter is designed without a guide wire lumen so as to be capable of rapid inflation and deflation of the balloon. The method comprises the following steps:(a)inserting an angiographic needle into the aorta;(b) passing the guide wire through the needle into the aorta;(c) removing the needle;(d) disposing the pull tube about the proximal end of the guide wire;(e) removing the pull tube from the self occluding lumen;(f) advancing the catheter into the aorta;(g) removing the guide wire from the aorta;(h) advancing the catheter up the aortic passageway to a position appropriate for pumping.