An arterial cannula that is too small, in addition to limiting flow,can causehigh pressuresgradient, cavitation, increased jet of flow velocities, jetting against the arterial wall and can increase the likelihood of dissection, and high shear forces which may damage the formed elements of the blood. However, diffusion-tip cannulas are available which provide multidirectional flow to reduce jets.[5]The tip of the cannula may be straight, tapered, or angled, as well as made from metal or plastic. Various tip modifications, such as flanges or adjustable rings, are available to prevent the cannula from being inserted too far into the aorta and impeding flow to the head vessels.[6] The inappropriately aortic cannulation can be associated with complications like bleeding, aortic dissection, malposition of cannula tip, atheroma dislodgement causing systemic embolism, accidental decannulation, aortic posterior wall puncture causing fatal bleeding and esophagealdamage. [7,8]

Our patient developed repeated LV distensions and cardiac arrests, even after repeated successful weaning from the CPB. Trans -esophagealechocardiography (TEE) was used to confirm any unnoticed congenital anomalies like PDA, ASD, coartation of the aorta, extra VSD, and VSD patch closure. After exclusion of the other possible causes of LV dysfunction and cardiac arrest,finally we reached to the decision that the repeated episodes of cardiac arrests were related tothe rarer complication i.e. the aortic blood flow obstruction by the use of large aortic cannula. The LV dysfunction and cardiac arrests were even refractory to the very high doses of inotropes, inodilators and standard CPR, but at last LV dysfunctions and hemodynamic graduallyimproved only after aortic decannulation. This complication of aortic cannulation has been hypothesized but not reported in the existing literature till date.