Sujoy Banik1, Hemanshu Prabhakar2. 1. Department of Neuroanaesthesiology, Neurosciences Center, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India. 2. Department of Neuroanaesthesiology, Neurosciences Center, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India. prabhakaraiims@yahoo.co.in.