Taghizadieh A, Nia K, Moharramzadeh P, Pouraghaei M, Ghavidel A, Parsian Z. The PCQP score for volume status of acutely ill patients: Integrating vascular pedicle width, caval index, respiratory variability of the qrs complex and R wave amplitude. Indian J Crit Care Med 2017; 21 (11):726-732.