1 All India Institute of Medical Sciences, Pain Medicine and Critical Care, Department of Anaesthesiology, Ansari Nagar, Índia. Electronic address: vimirewari@gmail.com.
2 All India Institute of Medical Sciences, Pain Medicine and Critical Care, Department of Anaesthesiology, Ansari Nagar, Índia.
3 All India Institute of Medical Sciences, Department of Otorhinolaryngology, Ansari Nagar, Índia.