Nilay Chatterjee1,2, Josemine Davis1, Arimanickam Ganesamoorthi1. 1. Department of Neuroanesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India. 2. Department of Pain Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.