Is There an Optimal Positive End-Expiratory Pressure to Measure the Internal Jugular Vein Collapsibility Index? A Pilot Study in Mechanically Ventilated Patients - Zeraatchi, Alireza; Naghibi, Taraneh; Kafili, Hamid; Abdollahi Sabet, Somayyeh (Archives of Anesthesiology and Critical Care, 2021)